path: root/doc/rfc/rfc8011.txt

Internet Engineering Task Force (IETF)                          M. Sweet
Request for Comments: 8011                                    Apple Inc.
Obsoletes: 2911, 3381, 3382                                  I. McDonald
Category: Standards Track                               High North, Inc.
ISSN: 2070-1721                                             January 2017


          Internet Printing Protocol/1.1: Model and Semantics

Abstract

   The Internet Printing Protocol (IPP) is an application-level protocol
   for distributed printing using Internet tools and technologies.  This
   document describes a simplified model consisting of abstract objects,
   attributes, and operations that is independent of encoding and
   transport.  The model consists of several objects, including Printers
   and Jobs.  Jobs optionally support multiple Documents.

   IPP semantics allow End Users and Operators to query Printer
   capabilities; submit Print Jobs; inquire about the status of Print
   Jobs and Printers; and cancel, hold, and release Print Jobs.  IPP
   semantics also allow Operators to pause and resume Jobs and Printers.

   Security, internationalization, and directory issues are also
   addressed by the model and semantics.  The IPP message encoding and
   transport are described in "Internet Printing Protocol/1.1: Encoding
   and Transport" (RFC 8010).

   This document obsoletes RFCs 2911, 3381, and 3382.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc8011.








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Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





































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Table of Contents

   1. Introduction ....................................................9
      1.1. Simplified Printing Model .................................12
   2. Conventions Used in This Document ..............................15
      2.1. Requirements Language .....................................15
      2.2. Printing Terminology ......................................15
      2.3. Model Terminology .........................................16
           2.3.1. Administrator ......................................16
           2.3.2. Attributes .........................................16
                  2.3.2.1. Attribute Group Name ......................16
                  2.3.2.2. Attribute Name ............................16
                  2.3.2.3. Attribute Syntax ..........................16
                  2.3.2.4. Attribute Value ...........................17
           2.3.3. End User ...........................................17
           2.3.4. Impression .........................................17
           2.3.5. Input Page .........................................17
           2.3.6. Job Creation Operation .............................17
           2.3.7. Keyword ............................................17
           2.3.8. Media Sheet ........................................18
           2.3.9. Operator ...........................................18
           2.3.10. Set ...............................................18
           2.3.11. Support of Attributes .............................18
           2.3.12. Terminating State .................................21
      2.4. Abbreviations .............................................21
   3. IPP Objects ....................................................22
      3.1. Printer Object ............................................22
      3.2. Job Object ................................................25
      3.3. Object Relationships ......................................25
      3.4. Object Identity ...........................................26
   4. IPP Operations .................................................29
      4.1. Common Semantics ..........................................30
           4.1.1. Required Parameters ................................30
           4.1.2. Operation IDs and Request IDs ......................31
           4.1.3. Attributes .........................................31
           4.1.4. Character Set and Natural Language
                  Operation Attributes ...............................33
                  4.1.4.1. Request Operation Attributes ..............34
                  4.1.4.2. Response Operation Attributes .............38
           4.1.5. Operation Targets ..................................39
           4.1.6. Operation Response Status-Code Values and
                  Status Messages ....................................41
                  4.1.6.1. "status-code" (type2 enum) ................41
                  4.1.6.2. "status-message" (text(255)) ..............42
                  4.1.6.3. "detailed-status-message" (text(MAX)) .....43
                  4.1.6.4. "document-access-error" (text(MAX)) .......43





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           4.1.7. Unsupported Attributes .............................44
           4.1.8. Versions ...........................................45
           4.1.9. Job Creation Operations ............................48
      4.2. Printer Operations ........................................50
           4.2.1. Print-Job Operation ................................51
                  4.2.1.1. Print-Job Request .........................51
                  4.2.1.2. Print-Job Response ........................56
           4.2.2. Print-URI Operation ................................58
           4.2.3. Validate-Job Operation .............................59
           4.2.4. Create-Job Operation ...............................59
           4.2.5. Get-Printer-Attributes Operation ...................60
                  4.2.5.1. Get-Printer-Attributes Request ............61
                  4.2.5.2. Get-Printer-Attributes Response ...........63
           4.2.6. Get-Jobs Operation .................................64
                  4.2.6.1. Get-Jobs Request ..........................65
                  4.2.6.2. Get-Jobs Response .........................66
           4.2.7. Pause-Printer Operation ............................68
                  4.2.7.1. Pause-Printer Request .....................71
                  4.2.7.2. Pause-Printer Response ....................71
           4.2.8. Resume-Printer Operation ...........................72
           4.2.9. Purge-Jobs Operation ...............................73
      4.3. Job Operations ............................................73
           4.3.1. Send-Document Operation ............................74
                  4.3.1.1. Send-Document Request .....................75
                  4.3.1.2. Send-Document Response ....................77
           4.3.2. Send-URI Operation .................................78
           4.3.3. Cancel-Job Operation ...............................78
                  4.3.3.1. Cancel-Job Request ........................80
                  4.3.3.2. Cancel-Job Response .......................81
           4.3.4. Get-Job-Attributes Operation .......................81
                  4.3.4.1. Get-Job-Attributes Request ................82
                  4.3.4.2. Get-Job-Attributes Response ...............83
           4.3.5. Hold-Job Operation .................................84
                  4.3.5.1. Hold-Job Request ..........................86
                  4.3.5.2. Hold-Job Response .........................87
           4.3.6. Release-Job Operation ..............................87
           4.3.7. Restart-Job Operation ..............................89
                  4.3.7.1. Restart-Job Request .......................91
                  4.3.7.2. Restart-Job Response ......................92
   5. Object Attributes ..............................................92
      5.1. Attribute Syntaxes ........................................92
           5.1.1. Out-of-Band Values - 'unknown',
                  'unsupported', and 'no-value' ......................93
           5.1.2. 'text' .............................................93
                  5.1.2.1. 'textWithoutLanguage' .....................94
                  5.1.2.2. 'textWithLanguage' ........................94





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           5.1.3. 'name' .............................................95
                  5.1.3.1. 'nameWithoutLanguage' .....................96
                  5.1.3.2. 'nameWithLanguage' ........................96
                  5.1.3.3. Matching 'name' Attribute Values ..........97
           5.1.4. 'keyword' ..........................................98
           5.1.5. 'enum' .............................................99
           5.1.6. 'uri' .............................................100
           5.1.7. 'uriScheme' .......................................100
           5.1.8. 'charset' .........................................101
           5.1.9. 'naturalLanguage' .................................102
           5.1.10. 'mimeMediaType' ..................................102
                  5.1.10.1. 'application/octet-stream' -
                            Auto-Sensing the Document Format ........103
           5.1.11. 'octetString' ....................................104
           5.1.12. 'boolean' ........................................104
           5.1.13. 'integer' ........................................104
           5.1.14. 'rangeOfInteger' .................................105
           5.1.15. 'dateTime' .......................................105
           5.1.16. 'resolution' .....................................105
           5.1.17. 'collection' .....................................105
           5.1.18. '1setOf X' .......................................106
      5.2. Job Template Attributes ..................................106
           5.2.1. job-priority (integer(1:100)) .....................109
           5.2.2. job-hold-until (type2 keyword | name(MAX)) ........111
           5.2.3. job-sheets (type2 keyword | name(MAX)) ............112
           5.2.4. multiple-document-handling (type2 keyword) ........113
           5.2.5. copies (integer(1:MAX)) ...........................115
           5.2.6. finishings (1setOf type2 enum) ....................115
           5.2.7. page-ranges (1setOf rangeOfInteger(1:MAX)) ........118
           5.2.8. sides (type2 keyword) .............................119
           5.2.9. number-up (integer(1:MAX)) ........................120
           5.2.10. orientation-requested (type2 enum) ...............120
           5.2.11. media (type2 keyword | name(MAX)) ................123
           5.2.12. printer-resolution (resolution) ..................124
           5.2.13. print-quality (type2 enum) .......................124
      5.3. Job Description and Status Attributes ....................124
           5.3.1. job-id (integer(1:MAX)) ...........................126
           5.3.2. job-uri (uri) .....................................126
           5.3.3. job-printer-uri (uri) .............................127
           5.3.4. job-more-info (uri) ...............................127
           5.3.5. job-name (name(MAX)) ..............................127
           5.3.6. job-originating-user-name (name(MAX)) .............128
           5.3.7. job-state (type1 enum) ............................128
                  5.3.7.1. Forwarding Servers .......................132
                  5.3.7.2. Partitioning of Job States ...............132
           5.3.8. job-state-reasons (1setOf type2 keyword) ..........133
           5.3.9. job-state-message (text(MAX)) .....................138
           5.3.10. job-detailed-status-messages (1setOf text(MAX)) ..139



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           5.3.11. job-document-access-errors (1setOf text(MAX)) ....139
           5.3.12. number-of-documents (integer(0:MAX)) .............139
           5.3.13. output-device-assigned (name(127)) ...............139
           5.3.14. Event Time Job Status Attributes .................140
                  5.3.14.1. time-at-creation (integer(MIN:MAX)) .....140
                  5.3.14.2. time-at-processing (integer(MIN:MAX)) ...141
                  5.3.14.3. time-at-completed (integer(MIN:MAX)) ....141
                  5.3.14.4. job-printer-up-time (integer(1:MAX)) ....141
                  5.3.14.5. date-time-at-creation
                            (dateTime|unknown) ......................141
                  5.3.14.6. date-time-at-processing
                            (dateTime|unknown|no-value) .............141
                  5.3.14.7. date-time-at-completed
                            (dateTime|unknown|no-value) .............141
           5.3.15. number-of-intervening-jobs (integer(0:MAX)) ......142
           5.3.16. job-message-from-operator (text(127)) ............142
           5.3.17. Job Size Attributes ..............................142
                  5.3.17.1. job-k-octets (integer(0:MAX)) ...........142
                  5.3.17.2. job-impressions (integer(0:MAX)) ........143
                  5.3.17.3. job-media-sheets (integer(1:MAX)) .......143
           5.3.18. Job Progress Attributes ..........................144
                  5.3.18.1. job-k-octets-processed
                            (integer(0:MAX)) ........................144
                  5.3.18.2. job-impressions-completed
                            (integer(0:MAX)) ........................144
                  5.3.18.3. job-media-sheets-completed
                            (integer(0:MAX)) ........................144
           5.3.19. attributes-charset (charset) .....................144
           5.3.20. attributes-natural-language (naturalLanguage) ....145
      5.4. Printer Description and Status Attributes ................145
           5.4.1. printer-uri-supported (1setOf uri) ................147
           5.4.2. uri-authentication-supported (1setOf type2
                  keyword) ..........................................148
           5.4.3. uri-security-supported (1setOf type2 keyword) .....149
           5.4.4. printer-name (name(127)) ..........................150
           5.4.5. printer-location (text(127)) ......................150
           5.4.6. printer-info (text(127)) ..........................151
           5.4.7. printer-more-info (uri) ...........................151
           5.4.8. printer-driver-installer (uri) ....................151
           5.4.9. printer-make-and-model (text(127)) ................151
           5.4.10. printer-more-info-manufacturer (uri) .............151
           5.4.11. printer-state (type1 enum) .......................152
           5.4.12. printer-state-reasons (1setOf type2 keyword) .....152
           5.4.13. printer-state-message (text(MAX)) ................157
           5.4.14. ipp-versions-supported (1setOf type2 keyword) ....157
           5.4.15. operations-supported (1setOf type2 enum) .........157





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           5.4.16. multiple-document-jobs-supported (boolean) .......159
           5.4.17. charset-configured (charset) .....................159
           5.4.18. charset-supported (1setOf charset) ...............159
           5.4.19. natural-language-configured (naturalLanguage) ....160
           5.4.20. generated-natural-language-supported
                   (1setOf naturalLanguage) .........................160
           5.4.21. document-format-default (mimeMediaType) ..........160
           5.4.22. document-format-supported (1setOf
                   mimeMediaType) ...................................161
           5.4.23. printer-is-accepting-jobs (boolean) ..............161
           5.4.24. queued-job-count (integer(0:MAX)) ................161
           5.4.25. printer-message-from-operator (text(127)) ........161
           5.4.26. color-supported (boolean) ........................161
           5.4.27. reference-uri-schemes-supported (1setOf
                   uriScheme) .......................................162
           5.4.28. pdl-override-supported (type2 keyword) ...........162
           5.4.29. printer-up-time (integer(1:MAX)) .................162
           5.4.30. printer-current-time (dateTime|unknown) ..........163
           5.4.31. multiple-operation-time-out (integer(1:MAX)) .....164
           5.4.32. compression-supported (1setOf type2 keyword) .....164
           5.4.33. job-k-octets-supported (rangeOfInteger(0:MAX)) ...165
           5.4.34. job-impressions-supported
                   (rangeOfInteger(0:MAX)) ..........................165
           5.4.35. job-media-sheets-supported
                   (rangeOfInteger(1:MAX)) ..........................165
           5.4.36. pages-per-minute (integer(0:MAX)) ................165
           5.4.37. pages-per-minute-color (integer(0:MAX)) ..........165
   6. Conformance ...................................................166
      6.1. Client Conformance Requirements ..........................166
      6.2. IPP Object Conformance Requirements ......................168
           6.2.1. Objects ...........................................168
           6.2.2. Operations ........................................168
           6.2.3. IPP Object Attributes .............................170
           6.2.4. Versions ..........................................170
           6.2.5. Extensions ........................................171
           6.2.6. Attribute Syntaxes ................................171
           6.2.7. Security ..........................................172
      6.3. Charset and Natural Language Requirements ................172
   7. IANA Considerations ...........................................173
      7.1. Object Extensions ........................................174
      7.2. Attribute Extensibility ..................................174
      7.3. Keyword Extensibility ....................................175
      7.4. Enum Extensibility .......................................176
      7.5. Attribute Group Extensibility ............................176
      7.6. Out-of-Band Attribute Value Extensibility ................176
      7.7. Attribute Syntax Extensibility ...........................177
      7.8. Operation Extensibility ..................................177
      7.9. Status-Code Extensibility ................................178



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   8. Internationalization Considerations ...........................179
   9. Security Considerations .......................................183
      9.1. Security Scenarios .......................................184
           9.1.1. Client and Server in the Same Security Domain .....184
           9.1.2. Client and Server in Different Security Domains ...184
           9.1.3. Print by Reference ................................184
      9.2. URIs in Operation, Job, and Printer Attributes ...........185
      9.3. URIs for Each Authentication Mechanism ...................185
      9.4. Restricted Queries .......................................186
      9.5. Operations Performed by Operators and Administrators .....186
      9.6. Queries on Jobs Submitted Using Non-IPP Protocols ........186
   10. Changes since RFC 2911 .......................................187
   11. References ...................................................188
      11.1. Normative References ....................................188
      11.2. Informative References ..................................194
   Appendix A. Formats for IPP Registration Proposals ...............197
     A.1. Attribute Registration ....................................197
     A.2. type2 'keyword' Attribute Value Registration ..............198
     A.3. type2 'enum' Attribute Value Registration .................198
     A.4. Operation Registration ....................................199
     A.5. Status-Code Registration ..................................199
   Appendix B. Status-Code Values and Suggested Status-Code
               Messages .............................................200
     B.1. Status-Code Values ........................................201
       B.1.1. Informational .........................................201
       B.1.2. Successful Status-Code Values .........................201
         B.1.2.1. successful-ok (0x0000) ............................201
         B.1.2.2. successful-ok-ignored-or-substituted-attributes
                  (0x0001) ..........................................202
         B.1.2.3. successful-ok-conflicting-attributes (0x0002) .....202
       B.1.3. Redirection Status-Code Values ........................202
       B.1.4. Client Error Status-Code Values .......................202
         B.1.4.1. client-error-bad-request (0x0400) .................203
         B.1.4.2. client-error-forbidden (0x0401) ...................203
         B.1.4.3. client-error-not-authenticated (0x0402) ...........203
         B.1.4.4. client-error-not-authorized (0x0403) ..............203
         B.1.4.5. client-error-not-possible (0x0404) ................203
         B.1.4.6. client-error-timeout (0x0405) .....................204
         B.1.4.7. client-error-not-found (0x0406) ...................204
         B.1.4.8. client-error-gone (0x0407) ........................204
         B.1.4.9. client-error-request-entity-too-large (0x0408) ....205
         B.1.4.10. client-error-request-value-too-long (0x0409) .....205
         B.1.4.11. client-error-document-format-not-supported
                   (0x040a) .........................................205
         B.1.4.12. client-error-attributes-or-values-not-supported
                   (0x040b) .........................................206
         B.1.4.13. client-error-uri-scheme-not-supported (0x040c) ...206
         B.1.4.14. client-error-charset-not-supported (0x040d) ......206



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         B.1.4.15. client-error-conflicting-attributes (0x040e) .....207
         B.1.4.16. client-error-compression-not-supported (0x040f) ..207
         B.1.4.17. client-error-compression-error (0x0410) ..........207
         B.1.4.18. client-error-document-format-error (0x0411) ......207
         B.1.4.19. client-error-document-access-error (0x0412) ......207
       B.1.5. Server Error Status-Code Values .......................208
         B.1.5.1. server-error-internal-error (0x0500) ..............208
         B.1.5.2. server-error-operation-not-supported (0x0501) .....208
         B.1.5.3. server-error-service-unavailable (0x0502) .........208
         B.1.5.4. server-error-version-not-supported (0x0503) .......209
         B.1.5.5. server-error-device-error (0x0504) ................209
         B.1.5.6. server-error-temporary-error (0x0505) .............210
         B.1.5.7. server-error-not-accepting-jobs (0x0506) ..........210
         B.1.5.8. server-error-busy (0x0507) ........................210
         B.1.5.9. server-error-job-canceled (0x0508) ................210
         B.1.5.10. server-error-multiple-document-jobs-not-supported
                   (0x0509) .........................................210
     B.2. Status-Code Values for IPP Operations .....................211
   Appendix C. Processing IPP Attributes ............................213
     C.1. Fidelity ..................................................213
     C.2. Page Description Language (PDL) Override ..................215
     C.3. Using Job Template Attributes during Document Processing ..217
   Appendix D. Generic Directory Schema .............................218
   Acknowledgements .................................................221
   Authors' Addresses ...............................................221

1.  Introduction

   The Internet Printing Protocol (IPP) is an application-level protocol
   for distributed printing using Internet tools and technologies.  IPP
   version 1.1 (IPP/1.1) focuses primarily on End User functionality
   with a few administrative operations included.  IPP versions 2.0,
   2.1, and 2.2 provide many new operations and are defined separately.

   This document is just one of a suite of documents that fully define
   IPP.  The full set of IETF IPP documents includes:

      Design Goals for an Internet Printing Protocol [RFC2567]

      Rationale for the Structure of the Model and Protocol for the
      Internet Printing Protocol [RFC2568]

      Internet Printing Protocol/1.1: Model and Semantics (this
      document)

      Internet Printing Protocol/1.1: Encoding and Transport [RFC8010]

      Internet Printing Protocol/1.1: Implementor's Guide [RFC3196]



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      Internet Printing Protocol/1.1: IPP URL Scheme [RFC3510]

      Internet Printing Protocol (IPP) over HTTPS Transport Binding and
      the 'ipps' URI Scheme [RFC7472]

      Internet Printing Protocol (IPP): Requirements for Job, Printer,
      and Device Administrative Operations [RFC3239]

      Internet Printing Protocol (IPP): Job and Printer Set Operations
      [RFC3380]

      Internet Printing Protocol (IPP): Job and Printer Administrative
      Operations [RFC3998]

      Internet Printing Protocol (IPP): Requirements for IPP
      Notifications [RFC3997]

      Internet Printing Protocol (IPP): Event Notifications and
      Subscriptions [RFC3995]

      Internet Printing Protocol (IPP): The 'ippget' Delivery Method for
      Event Notifications [RFC3996]

      Mapping between LPD and IPP Protocols [RFC2569]

   Anyone reading these documents for the first time is strongly
   encouraged to read the IPP documents in the above order.  Additional
   IPP specifications have been published by the IEEE-ISTO Printer
   Working Group's IPP Workgroup [PWG-IPP-WG].  The following standards
   are highly recommended reading:

      PWG Media Standardized Names 2.0 (MSN2) [PWG5101.1]

      IPP Finishings 2.0 (FIN) [PWG5100.1]

      Internet Printing Protocol (IPP): "output-bin" attribute extension
      [PWG5100.2]

      Internet Printing Protocol (IPP): Production Printing Attributes -
      Set 1 [PWG5100.3] (for "media-col" Job Template attribute)

      Standard for The Internet Printing Protocol (IPP): Document Object
      [PWG5100.5]

      Standard for The Internet Printing Protocol (IPP): Page Overrides
      [PWG5100.6]





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      Standard for The Internet Printing Protocol (IPP): Job Extensions
      [PWG5100.7]

      Standard for Internet Printing Protocol (IPP): "-actual"
      attributes [PWG5100.8]

      Internet Printing Protocol (IPP): Printer State Extensions v1.0
      [PWG5100.9]

      Internet Printing Protocol (IPP): Job and Printer Extensions -
      Set 2 (JPS2) [PWG5100.11]

      IPP Version 2.0, 2.1, and 2.2 [PWG5100.12]

      IPP: Job and Printer Extensions - Set 3 (JPS3) [PWG5100.13]

      IPP Everywhere [PWG5100.14]

      IPP FaxOut Service [PWG5100.15]

      IPP Transaction-Based Printing Extensions [PWG5100.16]

      IPP Scan Service (SCAN) [PWG5100.17]

      IPP Shared Infrastructure Extensions (INFRA) [PWG5100.18]

      IPP Implementor's Guide v2.0 (IG) [PWG5100.19]

   This document is organized as follows:

   o  The rest of Section 1 is an introduction to the IPP simplified
      model for distributed printing;

   o  Section 2 defines the terminology and conventions used within this
      document;

   o  Section 3 introduces the object types covered in this document
      with their basic behaviors, attributes, and interactions;

   o  Section 4 defines the core operations for IPP/1.1.  IPP operations
      are synchronous -- each operation has both a request and a
      response;

   o  Section 5 defines the core attributes (and their syntaxes) that
      are used in the model;






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   o  Sections 6 and 7 summarize the implementation conformance
      requirements for objects that support the protocol and IANA
      considerations, respectively;

   o  Sections 8 and 9 cover the internationalization and security
      considerations for IPP; and

   o  The appendices provide a reference for status-code values,
      processing of IPP attributes, and the generic directory schema.

1.1.  Simplified Printing Model

   In order to achieve its goal of realizing a workable printing
   protocol for the Internet, the Internet Printing Protocol (IPP) is
   based on a simplified printing model that abstracts the many
   components of real-world printing solutions.  The Internet is a
   distributed computing environment where requesters of print services
   (Clients, applications, Printer drivers, etc.) cooperate and interact
   with print service providers.  This document (sometimes referred to
   here as the "Model and Semantics" document) describes a simple,
   abstract model for IPP even though the underlying configurations can
   be complex "n-tier" client/server systems.  An important simplifying
   step in the IPP Model is to expose only the key objects and
   interfaces required for printing.  The model described in this
   document does not include features, interfaces, and relationships
   that are beyond the scope of IPP/1.1.  IPP/1.1 incorporates many of
   the relevant ideas and lessons learned from other specification and
   development efforts [HTPP] [ISO10175] [LDPA] [P1387.4] [PSIS]
   [RFC1179] [SWP].  IPP is heavily influenced by the printing model
   introduced in the Document Printing Application (DPA) [ISO10175]
   standard.  Although DPA specifies both End User and administrative
   features, IPP/1.1 focuses primarily on End User functionality with a
   few additional OPTIONAL operations for Administrators and Operators.

   The IPP Model encapsulates the important components of distributed
   printing into the following IPP object types:

   o  Printer (Section 3.1)

   o  Job (Section 3.2)

   o  Document (see [PWG5100.5])

   o  Subscription (see [RFC3995])

   Each object type has an associated set of operations (see Section 4)
   and attributes (see Section 5).




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   It is important, however, to understand that in real system
   implementations (which lie underneath the abstracted IPP Model),
   there are other components of a print service that are not explicitly
   defined in the IPP Model.  The following figure illustrates where IPP
   fits with respect to these other components.

                                +----------------+
                                |   Application  |
                      o         + . . . . . . .  |
                     \|/        |    Spooler     |
                     / \        + . . . . . . .  |   +---------+
                   End User     | Printer Driver |---|  File   |
         +-----------+ +-----+  +-------+--------+   +----+----+
         |  Browser  | | GUI |          |                 |
         +-----+-----+ +--+--+          |                 |
               |          |             |                 |
               |      +---+-------------+--+              |
   N   D   S   |      |      IPP Client    |--------------+
   O   I   E   |      +---------+----------+
   T   R   C   |                |
   I   E   U   |
   F   C   R   -------------- Transport -------------------
   I   T   I
   C   O   T                    |         --+
   A   R   Y           +--------+--------+  |
   T   Y               |    IPP Server   |  |
   I                   +--------+--------+  |
   O                            |           |
   N                   +-----------------+  | IPP Printer
                       |  Print Service  |  |
                       +-----------------+  |
                                |         --+
                       +-----------------+
                       | Output Device(s)|
                       +-----------------+

                            Figure 1: IPP Model

   An IPP Printer object ("Printer") encapsulates the functions normally
   associated with physical Output Devices along with the spooling,
   scheduling, and multiple device management functions often associated
   with a print server.  Printers are optionally registered as entries
   in a directory where End Users find and select them based on some
   sort of filtered context-based searching mechanism (see Appendix D).
   The directory is used to store relatively static information about
   the Printer, allowing End Users to search for and find Printers that
   match their search criteria -- for example, name, location, context,
   Printer capabilities, etc.  The more dynamic information, such as



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   state, currently loaded and ready media, number of Jobs at the
   Printer, errors, warnings, and so forth, is directly associated with
   the Printer itself rather than with the entry in the directory, which
   only references the Printer.

   IPP Clients ("Clients") implement IPP on the Client side and give
   End Users (or programs running on behalf of End Users) the ability to
   query Printers and submit and manage Print Jobs.  An IPP server is
   just that part of the Printer object that implements the server-side
   protocol.  The rest of the Printer object implements (or gateways
   into) the application semantics of the print service itself.
   Printers can be embedded in an Output Device or can be implemented on
   a host on the network that communicates with an Output Device.

   When a Job is submitted to the Printer and the Printer has validated
   the attributes in the submission request, the Printer creates a new
   IPP Job object ("Job").  The End User then interacts with this new
   Job to query its status and monitor the progress of the Job.  An
   End User can also cancel their Print Jobs by using the Job's
   Cancel-Job operation.  An End User can also hold, release, and
   restart their Print Jobs using the Job's OPTIONAL Hold-Job,
   Release-Job, and Restart-Job operations, if implemented.

   A privileged Operator or Administrator of a Printer can cancel, hold,
   release, and restart any user's Job using the REQUIRED Cancel-Job and
   the OPTIONAL Hold-Job, Release-Job, and Restart-Job operations.  In
   addition, a privileged Operator or Administrator of a Printer can
   pause, resume, or purge (Jobs from) a Printer using the OPTIONAL
   Pause-Printer, Resume-Printer, and Purge-Jobs operations, if
   implemented.

   The notification service is defined in "Internet Printing Protocol
   (IPP): Event Notifications and Subscriptions" [RFC3995].  By using
   such a notification service, the End User is able to register for and
   receive Printer-specific and Job-specific events asynchronously.
   Otherwise, an End User can query the status of Printers and can
   follow the progress of Jobs by polling using the
   Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes operations.













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2.  Conventions Used in This Document

2.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   The key word "DEPRECATED" in this document refers to an operation,
   attribute, or value that SHOULD NOT be used or supported in new
   implementations.

2.2.  Printing Terminology

   Client: Initiator of outgoing IPP session requests and sender of
   outgoing IPP operation requests (Hypertext Transfer Protocol
   (HTTP/1.1) user agent, as defined in [RFC7230]).

   Document: An object created and managed by a Printer that contains
   description, processing, and status information.  A Document object
   can have attached data and is bound to a single Job [PWG5100.5].

   'ipp' URI: An IPP URI as defined in [RFC3510].

   'ipps' URI: An IPP URI as defined in [RFC7472].

   Job: An object created and managed by a Printer that contains
   description, processing, and status information.  The Job also
   contains zero or more Document objects.

   Logical Device: A print server, software service, or gateway that
   processes Jobs and either forwards or stores the processed Job or
   uses one or more Physical Devices to render output.

   Output Device: A single Logical or Physical Device.

   Physical Device: A hardware implementation of an endpoint device,
   e.g., a marking engine, a fax modem, etc.

   Printer: Listener for incoming IPP session requests and receiver of
   incoming IPP operation requests (HTTP/1.1 server, as defined in
   [RFC7230]) that represents one or more Physical Devices or a Logical
   Device.








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2.3.  Model Terminology

2.3.1.  Administrator

   An End User who is also authorized to manage all aspects of an Output
   Device or Printer, including creating the Printer instances and
   controlling the authorization of other End Users and Operators
   [RFC2567].

2.3.2.  Attributes

   An attribute is an item of information that is associated with an
   instance of an IPP object (Printer, Job, etc.).  An attribute
   consists of an attribute name and one or more attribute values.  Each
   attribute has a specific attribute syntax.  All object attributes are
   defined in Section 5, and all operation attributes are defined in
   Section 4.

   Job Template attributes are described in Section 5.2.  The Client
   optionally supplies Job Template attributes in a Job Creation request
   (operation requests that create Job objects).  The Printer object has
   associated attributes that define supported and default values for
   the Printer.

2.3.2.1.  Attribute Group Name

   Related attributes are grouped into named groups.  The name of the
   group is a keyword.  The group name can be used in place of naming
   all the attributes in the group explicitly.  Attribute groups are
   defined in Section 4.

2.3.2.2.  Attribute Name

   Each attribute is uniquely identified in this document by its
   attribute name.  An attribute name is a keyword.  The keyword
   attribute name is given in the section title in this document that
   describes that attribute.  In running text in this document,
   attribute names are indicated inside double quotation marks (") where
   the quotation marks are not part of the keyword itself.

2.3.2.3.  Attribute Syntax

   Each attribute is defined using an explicit syntax type.  In this
   document, each syntax type is defined as a keyword with specific
   meaning.  The "Encoding and Transport" document [RFC8010] indicates
   the actual "on-the-wire" encoding rules for each syntax type.
   Attribute syntax types are defined in Section 5.1.




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2.3.2.4.  Attribute Value

   Each attribute has one or more values.  Attribute values are
   represented in the syntax type specified for that attribute.  In
   running text in this document, attribute values are indicated inside
   single quotation marks ('), whether their attribute syntax is
   keyword, integer, text, etc. where the quotation marks are not part
   of the value itself.

2.3.3.  End User

   An End User is a person or software process that is authorized to
   perform basic printing functions, including finding/locating a
   Printer, creating a local instance of a Printer, viewing Printer
   status, viewing Printer capabilities, submitting a Print Job, viewing
   Print Job status, and altering the attributes of a Print Job
   [RFC2567].

2.3.4.  Impression

   An Impression is the content imposed upon one side of a Media Sheet
   by a marking engine, independent of the number of times that the
   sheet side passes any marker.  An Impression contains one or more
   Input Pages that are imposed (scaled, translated, and/or rotated)
   during processing of the Document data.

2.3.5.  Input Page

   An Input Page is a page according to the definition of "pages" in the
   language used to express the Document data.

2.3.6.  Job Creation Operation

   A Job Creation operation is any operation that causes the creation of
   a Job object, e.g., the Create-Job, Print-Job, and Print-URI
   operations defined in this document.

2.3.7.  Keyword

   Keywords are used within this document as identifiers of semantic
   entities within the abstract model (see Section 5.1.4).  Attribute
   names, some attribute values, attribute syntaxes, and attribute group
   names are represented as keywords.








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2.3.8.  Media Sheet

   A Media Sheet is a single instance of a medium, whether printing on
   one or both sides of the medium.  Media Sheets also include sections
   of roll media.

2.3.9.  Operator

   An Operator is an End User that also has special rights on the Output
   Device or Printer.  The Operator typically monitors the status of the
   Printer and also manages and controls the Jobs at the Output Device
   [RFC2567].  The Operator is allowed to query and control the Printer,
   Jobs, and Documents based on site policy.

2.3.10.  Set

   A Set is a logical boundary between the delivered Media Sheets of a
   printed Job.  For example, in the case of a ten-page single Document
   with collated pages and a request for 50 copies, each of the 50
   printed copies of the Document constitutes a Set.  If the pages were
   uncollated, then 50 copies of each of the individual pages within the
   Document would represent each Set.  Finishing processes operate on
   Sets.

2.3.11.  Support of Attributes

   By definition, a Printer supports an attribute only if that Printer
   accepts it in a request or responds with the corresponding attribute
   populated with some value(s) in a response to a query for that
   attribute.  A Printer supports an attribute value if the value is one
   of the Printer's "supported values" attributes.  The device behind a
   Printer can exhibit a behavior that corresponds to some IPP
   attribute, but if the Printer, when queried for that attribute,
   doesn't respond with the attribute, then as far as IPP is concerned,
   that implementation does not support that feature.  If the Printer's
   "xxx-supported" attribute is not populated with a particular value
   (even if that value is a legal value for that attribute), then that
   Printer does not support that particular value.

   A conforming implementation supports all REQUIRED attributes.
   However, even for REQUIRED attributes, conformance to IPP does not
   mandate that all implementations support all possible values
   representing all possible Job processing behaviors and features.  For
   example, if a given instance of a Printer supports only certain
   Document formats, then that Printer responds with the
   "document-format-supported" attribute populated with a set of values,
   or possibly only one value, taken from the entire set of possible
   values defined for that attribute.  This limited set of values



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   represents the Printer's set of supported Document formats.
   Supporting an attribute and some set of values for that attribute
   enables IPP End Users to be aware of and make use of those features
   associated with that attribute and those values.  If an
   implementation chooses to not support an attribute or some specific
   value, then IPP End Users would have no ability to make use of that
   feature within the context of IPP itself.  However, due to existing
   practice and legacy systems that are not IPP aware, there might be
   some other mechanism outside the scope of IPP to control or request
   the "unsupported" feature (such as embedded instructions within the
   Document data itself).

   For example, consider the following for the "finishings-supported"
   attribute.

   1)  If a Printer is not physically capable of stapling, the
       "finishings-supported" attribute MUST NOT be populated with the
       value of 'staple'.

   2)  A Printer is physically capable of stapling; however, an
       implementation chooses not to support stapling in the IPP
       "finishings" attribute.  In this case, 'staple' MUST NOT be a
       value in the "finishings-supported" Printer Description
       attribute.  Without support for the value 'staple', an IPP
       End User would have no means within the protocol itself to
       request that a Job be stapled.  However, an existing Document
       data formatter might be able to request that the Document be
       stapled directly with an embedded instruction within the Document
       data.  In this case, the IPP implementation does not "support"
       stapling; however, the End User is still able to have some
       control over the stapling of the completed Job.

   3)  A Printer is physically capable of stapling, and an
       implementation chooses to support stapling in the IPP
       "finishings" attribute.  In this case, 'staple' MUST be a value
       in the "finishings-supported" Printer attribute.  Doing so
       enables End Users to be aware of and make use of the stapling
       feature using IPP attributes.

   Even though support for Job Template attributes by a Printer is
   OPTIONAL in IPP/1.1, Printers whose associated device(s) is capable
   of realizing any feature or function that corresponds to an IPP
   attribute and some associated value SHOULD support that IPP attribute
   and value.







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   The set of values in any of the supported value attributes is set
   (populated) by some administrative process or automatic sensing
   mechanism that is outside the scope of this document.  For
   administrative policy and control reasons, an Administrator can
   choose to make only a subset of possible values visible to the
   End User.  In this case, the real Output Device behind the IPP
   Printer abstraction can be capable of a certain feature; however, an
   Administrator is specifying that access to that feature not be
   exposed to the End User through IPP.  Also, since a Printer can
   represent a logical print device (not just a Physical Device), the
   actual process for supporting a value is undefined and left up to the
   implementation.  However, if a Printer supports a value, some manual
   human action might be needed to realize the semantic action
   associated with the value, but no End User action is required.

   For example, if one of the values in the "finishings-supported"
   attribute is 'staple', the actual process might be an automatic
   staple action by a Physical Device controlled by some command sent to
   the device.  Or, the actual process of stapling might be a manual
   action by an Operator at an Operator-attended Printer.

   For another example of how supported attributes function, consider an
   Administrator who desires to control all Print Jobs so that no Job
   sheets are printed in order to conserve paper.  To force no Job
   sheets, the Administrator sets the only supported value for the
   "job-sheets-supported" attribute to 'none'.  In this case, if a
   Client requests anything except 'none', the Job Creation request is
   rejected or the "job-sheets" value is ignored (depending on the value
   of "ipp-attribute-fidelity").  To force the use of Job start/end
   sheets on all Jobs, the Administrator does not include the value
   'none' in the "job-sheets-supported" attribute.  In this case, if a
   Client requests 'none', the Job Creation request is rejected or the
   "job-sheets" value is ignored (again depending on the value of
   "ipp-attribute-fidelity").

   Job Template attributes will typically have corresponding
   "xxx-supported" and "xxx-default" Printer Description attributes that
   contain the supported and default values for the attribute.  For
   capabilities that are not associated with a Job, the convention is to
   have an "xxx-supported" Printer Description attribute that lists the
   supported values and an "xxx-configured" Printer Description
   attribute that contains the value being used by the Printer.  For
   example, the "charset-supported" Printer Description attribute
   (Section 5.4.18) lists the supported character sets for the Printer
   while the "charset-configured" Printer Description attribute
   (Section 5.4.17) specifies the character set being used by the
   Printer.




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2.3.12.  Terminating State

   The final state for a Job or other object is called its Terminating
   State.  For example, the 'aborted', 'canceled', and 'completed' Job
   states are Terminating States.

2.4.  Abbreviations

   ABNF: Augmented Backus-Naur Form [RFC5234]

   ASCII: American Standard Code for Information Interchange [RFC20]

   HTTP: Hypertext Transfer Protocol [RFC7230]

   HTTPS: HTTP over TLS [RFC2818]

   IANA: Internet Assigned Numbers Authority

   IEEE: Institute of Electrical and Electronics Engineers

   IESG: Internet Engineering Steering Group

   IPP: Internet Printing Protocol (this document, [RFC8010], and
   [PWG5100.12])

   ISTO: IEEE Industry Standards and Technology Organization

   LPD: Line Printer Daemon Protocol [RFC1179]

   PWG: IEEE-ISTO Printer Working Group

   RFC: Request for Comments

   TCP: Transmission Control Protocol [RFC793]

   TLS: Transport Layer Security [RFC5246]

   URI: Uniform Resource Identifier [RFC3986]

   URL: Uniform Resource Locator [RFC3986]

   UTF-8: Unicode Transformation Format - 8-bit [RFC3629]









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3.  IPP Objects

   This document defines IPP objects of types Printer and Job.  Each
   type of object models relevant aspects of a real-world entity such as
   a real Printer or real Print Job.  Each object type is defined as a
   set of possible attributes that can be supported by instances of that
   object type.  For each object (instance), the actual set of supported
   attributes and values describe a specific implementation.  The
   object's attributes and values describe its state, capabilities,
   realizable features, Job processing functions, and default behaviors
   and characteristics.  For example, the Printer object type is defined
   as a set of attributes that each Printer object potentially supports.
   In the same manner, the Job object type is defined as a set of
   attributes that are potentially supported by each Job object.

   Each attribute included in the set of attributes defining an object
   type is labeled as:

   o  "REQUIRED": each object MUST support the attribute.

   o  "RECOMMENDED": each object SHOULD support the attribute.

   o  "OPTIONAL": each object MAY support the attribute.

   Some definitions of attribute values indicate that an object MUST or
   SHOULD support the value; otherwise, support of the value is
   OPTIONAL.  However, if an implementation supports an attribute, it
   MUST support at least one of the possible values for that attribute.

3.1.  Printer Object

   The major component of the IPP Model is the Printer object.  A
   Printer object implements the server side of the IPP/1.1 protocol.
   Using the protocol, End Users can query the attributes of the Printer
   object and submit Print Jobs to the Printer object.  The actual
   implementation components behind the Printer abstraction can take on
   different forms and different configurations.  However, the model
   abstraction allows the details of the configuration of real
   components to remain opaque to the End User.  Section 4 describes
   each of the Printer operations in detail.











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   The capabilities and state of a Printer object are described by its
   attributes.  Printer attributes are divided into two groups:

   o  "job-template" attributes: These attributes describe supported Job
      processing capabilities and defaults for the Printer object (see
      Section 5.2)

   o  "printer-description" attributes: These attributes describe the
      Printer's identification, state, location, references to other
      sources of information about the Printer object, etc. (see
      Section 5.4)

   Since a Printer object is an abstraction of a generic Document Output
   Device and print service provider, a Printer object could be used to
   represent any real or virtual device with semantics consistent with
   the Printer object, such as a fax device, an imager, or even a CD
   writer.

   Some examples of configurations supporting a Printer object include:

   1.  An Output Device with no spooling capabilities

   2.  An Output Device with a built-in spooler

   3.  A print server supporting IPP with one or more associated Output
       Devices

       3a.  The associated Output Devices are or are not capable of
            spooling Jobs

       3b.  The associated Output Devices possibly support IPP

   Figure 2 shows some examples of how Printers can be realized on top
   of various distributed printing configurations.  The embedded case
   below represents configurations 1 and 2 above.  The "hosted Printer"
   and "fan out" items represent configurations 3a and 3b, respectively.

   In this document, the term "Client" refers to a software entity that
   sends IPP operation requests to an IPP Printer and accepts IPP
   operation responses.  A Client MAY be:

   1.  contained within software controlled by an End User, e.g.,
       activated by the "Print" menu item in an application, or

   2.  the print server component that sends IPP requests to either an
       Output Device or another "downstream" print server.





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   The term "IPP Printer" is a network entity that accepts IPP operation
   requests and returns IPP operation responses.  As such, an IPP
   Printer object MAY be:

   1.  an (embedded) device component that accepts IPP requests and
       controls the device, or

   2.  a component of a print server that accepts IPP requests (where
       the print server controls one or more networked devices using IPP
       or other protocols).

   Legend:

   ##### indicates a Printer object that is
         either embedded in an Output Device or
         hosted in a server.  The Printer object
         might or might not be capable of queuing/spooling.

   any   indicates any network protocol or direct
         connect, including IPP

   embedded Printer:
                                             Output Device
                                           +---------------+
    O   +--------+                         |  ###########  |
   /|\  | Client |------------IPP------------># Printer #  |
   / \  +--------+                         |  # Object  #  |
                                           |  ###########  |
                                           +---------------+
   hosted Printer:
                                           +---------------+
    O   +--------+        ###########      |               |
   /|\  | Client |--IPP--># Printer #-any->| Output Device |
   / \  +--------+        # Object  #      |               |
                          ###########      +---------------+
                                            +---------------+
   fan out:                                 |               |
                                        +-->| Output Device |
                                    any/    |               |
    O   +--------+      ###########   /     +---------------+
   /|\  | Client |-IPP-># Printer #--*
   / \  +--------+      # Object  #   \     +---------------+
                        ########### any\    |               |
                                        +-->| Output Device |
                                            |               |
                                            +---------------+

                 Figure 2: IPP Printer Object Architecture



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3.2.  Job Object

   A Job object is used to model a Print Job.  A Job object contains
   zero or more Documents.  The information required to create a Job
   object is sent in a Job Creation request from the End User via an IPP
   Client to the Printer.  The Printer validates the Job Creation
   request, and if the Printer accepts the request, the Printer creates
   the new Job object.  Section 4 describes each of the Job operations
   in detail.

   The characteristics and state of a Job object are described by its
   attributes.  Job attributes are grouped into two groups as follows:

   o  "job-template" attributes: These attributes can be supplied by the
      Client or End User and include Job processing instructions that
      are intended to override any Printer defaults and/or instructions
      embedded within the Document data (see Section 5.2)

   o  "job-description" attributes: These attributes describe the Job's
      identification, state, size, etc.  The Client supplies some of
      these attributes, and the Printer generates others (see
      Section 5.3)

   An implementation MUST support at least one Document per Job object.
   An implementation MAY support multiple Documents per Job object.  A
   Document is either:

   o  a stream of Document data in a format supported by the Printer
      (typically a Page Description Language -- PDL), or

   o  a reference to such a stream of Document data.

   All Job processing instructions are modeled as Job object attributes.
   These attributes are called "Job Template attributes", and they apply
   equally to all Documents within a Job object.

3.3.  Object Relationships

   IPP objects have relationships that are maintained persistently along
   with the persistent storage of the object attributes.

   A Printer object can represent either one or more physical Output
   Devices or a Logical Device that "processes" Jobs but never actually
   uses a physical Output Device to put marks on paper.  Examples of
   Logical Devices include a web page publisher or a gateway into an
   online Document archive or repository.  A Printer contains zero or
   more Job objects.




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   A Job object is contained by exactly one Printer; however, the
   identical Document data associated with a Job could be sent to either
   the same or a different Printer.  In this case, a second Job object
   would be created that would be almost identical to the first Job;
   however, it would have new (different) Job object identifiers (see
   Section 3.4).

   A Job either is empty (before any Documents have been added) or
   contains one or more Documents.  If the contained Document is a
   stream of Document data, that stream can be contained in only one
   Document.  However, there can be identical copies of the stream in
   other Documents in the same or different Jobs.  If the contained
   Document is just a reference to a stream of Document data, other
   Documents (in the same or different Job(s)) contain the same
   reference.

3.4.  Object Identity

   All IPP objects (Printers, Jobs, etc.) are identified by a Uniform
   Resource Identifier (URI) [RFC3986] so that they can be persistently
   and unambiguously referenced.  Since every URL is a specialized form
   of a URI, even though the more generic term "URI" is used throughout
   the rest of this document, its usage is intended to cover the more
   specific notion of "URL" as well.

   An Administrator configures Printers to either support or not support
   authentication and/or message privacy using Transport Layer Security
   (TLS) [RFC5246]; the mechanism for security configuration is outside
   the scope of this document.  In some situations, both types of
   connections (both authenticated and unauthenticated) can be
   established using a single communication channel that has some sort
   of negotiation mechanism.  In other situations, multiple
   communication channels are used, one for each type of security
   configuration.  Section 9 provides a full description of all security
   considerations and configurations.

   If a Printer supports more than one communication channel, some or
   all of those channels might support and/or require different security
   mechanisms.  In such cases, an Administrator could expose the
   simultaneous support for these multiple communication channels as
   multiple URIs for a single Printer where each URI represents one of
   the communication channels to the Printer.  To support this
   flexibility, the IPP Printer object type defines a multi-valued
   identification attribute called the "printer-uri-supported" attribute
   that MUST contain at least one URI.  The "printer-uri-supported"
   attribute has two companion attributes, the "uri-security-supported"
   attribute and the "uri-authentication-supported" attribute.  Both
   have the same cardinality as "printer-uri-supported".  The purpose of



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   the "uri-security-supported" attribute is to indicate the security
   mechanisms (if any) used for each URI listed in
   "printer-uri-supported".  The purpose of the
   "uri-authentication-supported" attribute is to indicate the
   authentication mechanisms (if any) used for each URI listed in
   "printer-uri-supported".  These three attributes are fully described
   in Sections 5.4.1, 5.4.2, and 5.4.3.

   When a Job is submitted to the Printer via a Job Creation request,
   the Client supplies only a single Printer URI.  The Client-supplied
   Printer URI MUST be one of the values in the "printer-uri-supported"
   Printer attribute.

   IPP/1.1 does not specify how the Client obtains the Client-supplied
   URI, but it is RECOMMENDED that a Printer be registered as an entry
   in a directory service.  End Users and programs can then interrogate
   the directory, searching for Printers.  Appendix D defines a generic
   schema for Printer object entries in the directory service and
   describes how the entry acts as a bridge to the actual IPP Printer.
   The entry in the directory that represents the IPP Printer includes
   the possibly many URIs for that Printer as values in one of its
   attributes.

   When a Client submits a Job Creation request to the Printer, the
   Printer validates the request and creates a new Job object.  The
   Printer assigns the new Job a numeric identifier that is stored in
   the "job-id" Job attribute and a URI that is stored in the "job-uri"
   Job attribute.  Both the numeric identifier and URI can then be used
   by Clients as the target for subsequent Job operations; the numeric
   identifier is preferred.  The Printer generates the Job numeric
   identifier and URI based on its configured security policy and the
   URI used by the Client in the Job Creation request.

   For example, consider a Printer that supports both a communication
   channel secured by the use of TLS (using HTTP over TLS with an
   "https" schemed URI) and another open communication channel that is
   not secured with TLS (using a simple "http" schemed URI).  If a
   Client submits a Job using the secure URI, the Printer assigns the
   new Job a secure URI as well.  If a Client were to submit a Job using
   the open-channel URI, the Printer might assign the new Job an
   open-channel URI.  Clients SHOULD use the "printer-uri" and "job-id"
   attributes to target a Job to avoid any ambiguity about the security
   of the communication channel.

   In addition, the Printer also populates the Job's "job-printer-uri"
   attribute.  This is a reference back to the Printer that created the
   Job.  If a Client only has access to a Job's "job-uri" identifier,
   the Client can query the Job's "job-printer-uri" attribute in order



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   to determine which Printer created the Job.  If the Printer supports
   more than one URI, the Printer picks the one URI supplied by the
   Client when creating the Job to build the value for and to populate
   the Job's "job-printer-uri" attribute.

   In addition to identifiers, IPP objects have names -- "printer-name"
   for Printers and "job-name" for Jobs.  An object name is not
   guaranteed to be unique across all instances of all objects.  A
   Printer's name is chosen and set by an Administrator through some
   mechanism outside the scope of this document.  A Job's name can be
   chosen and supplied by the Client submitting the Job.  If the Client
   does not supply a Job name, the Printer generates a name for the new
   Job.  In all cases, the name only has local meaning.

   To summarize:

   o  Each Printer is identified by one or more URIs.  The Printer's
      "printer-uri-supported" attribute contains the URI(s).

   o  The Printer's "uri-security-supported" attribute identifies the
      communication channel security protocols that have been configured
      for the various Printer URIs (e.g., 'tls' or 'none').

   o  The Printer's "uri-authentication-supported" attribute identifies
      the authentication mechanisms that have been configured for the
      various Printer URIs (e.g., 'digest', 'none', etc.).

   o  Each Job is identified by a numeric identifier, which is a 32-bit
      positive integer.  The Job's "job-id" attribute contains the
      Job ID.  The Job ID is only unique within the context of the
      Printer that created the Job.

   o  Each Job is also identified by a URI.  The Job's "job-uri"
      attribute contains the URI, although its use by Clients is
      DEPRECATED.

   o  Each Job has a "job-printer-uri" attribute, which contains the URI
      of the Printer that was used to create the Job.  This attribute is
      used to determine the Printer that created a Job when given only
      the URI for the Job.  This linkage is necessary to determine the
      languages, charsets, and operations that are supported on that Job
      (the basis for such support comes from the creating Printer).

   o  Each Printer has a name, which is not necessarily unique.  The
      Administrator chooses and sets this name through some mechanism
      outside the scope of this IPP/1.1 document.  The Printer's
      "printer-name" attribute contains the name.




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   o  Each Job has a name, which is not necessarily unique.  The Client
      optionally supplies this name in the Job Creation request.  If the
      Client does not supply this name, the Printer generates a name for
      the Job.  The Job's "job-name" attribute contains the name.

4.  IPP Operations

   IPP objects (Printers, Jobs, etc.) support operations.  An operation
   consists of a request and a response.  When a Client communicates
   with a Printer or its Jobs, the Client issues an operation request to
   the Printer URI and object's numeric identifier, if needed.
   Operation requests and responses have parameters that identify the
   operation.  Operations also have attributes that affect the runtime
   characteristics of the operation (the intended target, localization
   information, etc.).  These operation-specific attributes are called
   "operation attributes" (as compared to object attributes such as
   Printer attributes or Job attributes).  Each request carries along
   with it any operation attributes, object attributes, and/or Document
   data required to perform the operation.  Each request requires a
   response from the object.  Each response indicates success or failure
   of the operation with a status-code as a response parameter.  The
   response contains any operation attributes, object attributes, and/or
   status messages generated during the execution of the operation
   request.

   This section describes the semantics of the IPP operations, both
   requests and responses, in terms of the parameters, attributes, and
   other data associated with each operation.

   The Printer operations defined in this document are:

      Print-Job (Section 4.2.1)

      Print-URI (Section 4.2.2)

      Validate-Job (Section 4.2.3)

      Create-Job (Section 4.2.4)

      Get-Printer-Attributes (Section 4.2.5)

      Get-Jobs (Section 4.2.6)

      Pause-Printer (Section 4.2.7)

      Resume-Printer (Section 4.2.8)

      Purge-Jobs (Section 4.2.9)



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   The Job operations defined in this document are:

      Send-Document (Section 4.3.1)

      Send-URI (Section 4.3.2)

      Cancel-Job (Section 4.3.3)

      Get-Job-Attributes (Section 4.3.4)

      Hold-Job (Section 4.3.5)

      Release-Job (Section 4.3.6)

      Restart-Job (Section 4.3.7)

   The Send-Document and Send-URI Job operations are used to add
   Documents to an existing Job created using the Create-Job operation.

4.1.  Common Semantics

   All IPP operations require some common parameters and operation
   attributes.  These common elements and their semantic characteristics
   are defined and described in more detail in the following sections.

4.1.1.  Required Parameters

   Every operation request contains the following REQUIRED parameters:

   o  a "version-number",

   o  an "operation-id",

   o  a "request-id", and

   o  the attributes that are REQUIRED for that type of request.

   Every operation response contains the following REQUIRED parameters:

   o  a "version-number",

   o  a "status-code",

   o  the "request-id" that was supplied in the corresponding request,
      and

   o  the attributes that are REQUIRED for that type of response.




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   The Encoding and Transport document [RFC8010] defines special rules
   for the encoding of these parameters.  All other operation elements
   are represented using the more generic encoding rules for attributes
   and groups of attributes.

4.1.2.  Operation IDs and Request IDs

   Each IPP operation request includes an identifying "operation-id"
   value.  Valid values are defined in the "operations-supported"
   Printer attribute section (see Section 5.4.15).  The Client specifies
   which operation is being requested by supplying the correct
   "operation-id" value.

   In addition, every invocation of an operation is identified by a
   "request-id" value.  For each request, the Client chooses the
   "request-id", which MUST be an integer (possibly unique, depending on
   Client requirements) in the range from 1 to 2**31 - 1 (inclusive).
   This "request-id" allows Clients to manage multiple outstanding
   requests.  The receiving IPP object (Printer, Job, etc.) copies all
   32 bits of the Client-supplied "request-id" attribute into the
   response so that the Client can match the response with the correct
   outstanding request, even if the "request-id" is out of range.  If
   the request is terminated before the complete "request-id" is
   received, the IPP object rejects the request and returns a response
   with a "request-id" of 0.

   Note: In some cases, the transport protocol underneath IPP might be a
   connection-oriented protocol that would make it impossible for a
   Client to receive responses in any order other than the order in
   which the corresponding requests were sent.  In such cases, the
   "request-id" attribute would not be essential for correct protocol
   operation.  However, in other transport mappings the operation
   responses could come back in any order, in which case the
   "request-id" is essential.

4.1.3.  Attributes

   Operation requests and responses are both composed of groups of
   attributes and/or Document data.  The attribute groups are:

   o  Operation Attributes: These attributes are passed in the operation
      and affect the IPP object's behavior while processing the
      operation request, and they can affect other attributes or groups
      of attributes.  Some operation attributes describe the Document
      data associated with the Print Job and are associated with new Job
      objects; however, most operation attributes do not persist beyond
      the life of the operation.  The description of each operation
      attribute includes conformance statements indicating which



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      operation attributes are REQUIRED and which are OPTIONAL for an
      IPP object to support, as well as which attributes a Client MUST
      supply in a request and an IPP object MUST supply in a response.

   o  Job Template Attributes: These attributes affect the processing of
      a Job.  A Client MAY supply Job Template attributes in a Job
      Creation request, and the receiving object MUST be prepared to
      receive all supported attributes.  The Job object can later be
      queried to find out what Job Template attributes were originally
      requested in the Job Creation request, and such attributes are
      returned in the response as Job object attributes.  The Printer
      object can be queried about its Job Template attributes to find
      out what type of Job processing capabilities are supported and/or
      what the default Job processing behaviors are, though such
      attributes are returned in the response as Printer object
      attributes.  The "ipp-attribute-fidelity" operation attribute
      affects processing of all Client-supplied Job Template attributes
      -- see Section 4.2.1.1 and Appendix C for a full description of
      "ipp-attribute-fidelity" and its relationship to other attributes.

   o  Job Object Attributes: These attributes are returned in response
      to a query operation directed at a Job object.

   o  Printer Object Attributes: These attributes are returned in
      response to a query operation directed at a Printer object.

   o  Unsupported Attributes: In a Job Creation request, the Client
      supplies a set of operation and Job Template attributes.  If any
      of these attributes or their values are unsupported by the Printer
      object, the Printer object SHOULD return the set of unsupported
      attributes in the response.  Section 4.1.7, Section 4.2.1.2, and
      Appendix C give a full description of how Job Template attributes
      supplied by the Client in a Job Creation request are processed by
      the Printer object and how unsupported attributes are returned to
      the Client.  Because of extensibility, any IPP object might
      receive a request that contains new or unknown attributes or
      values for which it has no support.  In such cases, the IPP object
      processes what it can and returns the unsupported attributes in
      the response.  The Unsupported Attributes group is defined for all
      operation responses for returning unsupported attributes that the
      Client supplied in the request.

   Later in this section, each operation is formally defined by
   identifying the allowed and expected groups of attributes for each
   request and response.  The model identifies a specific order for each
   group in each request or response, but the attributes within each
   group can be in any order, unless specified otherwise.




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   The attributes within a group MUST be unique; if an attribute with
   the same name occurs more than once, the group is malformed.  Clients
   MUST NOT submit such malformed requests, and Printers MUST NOT return
   such malformed responses.  If such a malformed request is submitted
   to a Printer, the Printer MUST either (1) reject the request with the
   'client-error-bad-request' status-code (RECOMMENDED -- see
   Appendix B.1.4.1) or (2) process the request normally after selecting
   only one of the attribute instances, depending on implementation.
   Which attribute is selected when there are duplicate attributes
   depends on implementation.  The IPP Printer MUST NOT use the values
   from more than one such duplicate attribute instance.

   Each attribute definition includes the attribute's name followed by
   the name of its attribute syntax(es) in parentheses.  In addition,
   each 'integer' attribute can be followed by the allowed range in
   parentheses, (m:n), for values of that attribute.  Each 'text' or
   'name' attribute can be followed by the maximum size in octets in
   parentheses, (size), for values of that attribute.  For more details
   on attribute syntax notation, see the descriptions of these attribute
   syntaxes in Section 5.1.

   Note: Document data included in the operation is not strictly an
   attribute, but it is treated as a special attribute group for
   ordering purposes.  The only operations defined in this document that
   support supplying the Document data within an operation request are
   Print-Job and Send-Document.  There are no operations defined in this
   document whose responses include Document data.

   Some operations are REQUIRED for IPP objects to support; the others
   are OPTIONAL (see Section 6.2.2).  Therefore, before using an
   OPTIONAL operation, a Client SHOULD first use the REQUIRED
   Get-Printer-Attributes operation to query the Printer's
   "operations-supported" attribute in order to determine which OPTIONAL
   operations are actually supported.  The Client SHOULD NOT use an
   OPTIONAL operation that is not supported.  When an IPP object
   receives a request to perform an operation it does not support, it
   MUST return the 'server-error-operation-not-supported' status-code
   (see Appendix B.1.5.2).  An IPP object is non-conformant if it does
   not support a REQUIRED operation.

4.1.4.  Character Set and Natural Language Operation Attributes

   Some Job and Printer attributes have values that are text strings and
   names intended for human understanding rather than machine
   understanding (see the 'text' and 'name' attribute syntax
   descriptions in Section 5.1).  The following sections describe two
   special operation attributes called "attributes-charset" and
   "attributes-natural-language" whose values are used when interpreting



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   other attributes using the 'text' and 'name' attribute syntaxes.  For
   Job Creation operations, the IPP Printer implementation also saves
   these two attributes with the new Job object as Job Status
   attributes.

   The "attributes-charset" and "attributes-natural-language" attributes
   MUST be the first two attributes in every IPP request and response,
   as part of the initial Operation Attributes group of the IPP message.
   The "attributes-charset" attribute MUST be the first attribute in the
   group, and the "attributes-natural-language" attribute MUST be the
   second attribute in the group.

   For the sake of brevity in this document, these operation attribute
   descriptions are not repeated with every operation request and
   response but instead have a reference back to this section.

4.1.4.1.  Request Operation Attributes

   The Client MUST supply and the Printer object MUST support the
   following REQUIRED operation attributes in every IPP operation
   request:

   "attributes-charset" (charset):

      This operation attribute identifies the charset (coded character
      set and encoding method) used by any 'text' and 'name' attributes
      that the Client is supplying in this request.  It also identifies
      the charset that the Printer object MUST use (if supported) for
      all 'text' and 'name' attributes and status messages that the
      Printer object returns in the response to this request.  See
      Sections 5.1.2 and 5.1.3 for the definitions of the 'text' and
      'name' attribute syntaxes.

      All Clients and IPP objects MUST support the 'utf-8' charset
      [RFC3629] and MAY support additional charsets, provided that they
      are registered with IANA [RFC2978] [IANA-CS].  If the Printer
      object does not support the Client-supplied charset value, the
      Printer object MUST reject the request, set the
      "attributes-charset" to 'utf-8' in the response, and return the
      'client-error-charset-not-supported' status-code and any 'text' or
      'name' attributes using the 'utf-8' charset.  The Printer MAY
      return any attributes in the Unsupported Attributes group (see
      Sections 4.1.7 and 4.2.1.2).  The Printer object MUST indicate the
      charset(s) supported as the values of the "charset-supported"
      Printer attribute (see Section 5.4.18), so that the Client can
      query to determine which charset(s) is supported.





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      Note to Client implementors: Since IPP objects are only required
      to support the 'utf-8' charset, in order to maximize
      interoperability with multiple IPP object implementations, a
      Client SHOULD supply 'utf-8' in the "attributes-charset" operation
      attribute, even though the Client is only passing and able to
      present a simpler charset, such as US-ASCII [RFC20] or ISO-8859-1
      [ISO8859-1].  Then the Client will have to filter out, perform
      charset conversion on, or replace those characters that are
      returned in the response that it cannot present to its user.  On
      the other hand, if both the Client and the IPP objects also
      support a charset in common besides 'utf-8', the Client can use
      that charset in order to avoid charset conversion or data loss.

      See the 'charset' attribute syntax description in Section 5.1.8
      for the syntax and semantic interpretation of the values of this
      attribute and for example values.

   "attributes-natural-language" (naturalLanguage):

      This operation attribute identifies the natural language [RFC5646]
      used by any 'text' and 'name' attributes that the Client is
      supplying in this request.  This attribute also identifies the
      natural language that the Printer object SHOULD use for all 'text'
      and 'name' attributes and status messages that the Printer object
      returns in the response to this request.  See the
      'naturalLanguage' attribute syntax description in Section 5.1.9
      for the syntax and semantic interpretation of the values of this
      attribute and for example values.

      There are no REQUIRED natural languages required for the Printer
      object to support.  However, the Printer's
      "generated-natural-language-supported" attribute identifies the
      natural languages supported by the Printer object and any
      contained Jobs for all text strings generated by the IPP object.
      A Client MAY query this attribute to determine which natural
      language(s) is supported for generated messages.

      For any of the attributes for which the Printer object generates
      text, i.e., for the "job-state-message", "printer-state-message",
      and status messages (see Section 4.1.6), the Printer object MUST
      be able to generate these text strings in any of its supported
      natural languages.  If the Client requests a natural language that
      is not supported, the Printer object MUST return these generated
      messages in the Printer's configured natural language as specified
      by the Printer's "natural-language-configured" attribute (see
      Section 5.4.19).





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      For other 'text' and 'name' attributes supplied by the Client,
      authentication system, Operator, Administrator, or manufacturer
      (i.e., for "job-originating-user-name", "printer-name" (name),
      "printer-location" (text), "printer-info" (text), and
      "printer-make-and-model" (text)), the Printer object is only
      required to support the configured natural language of the Printer
      identified by the Printer's "natural-language-configured"
      attribute, though support of additional natural languages for
      these attributes is permitted.

      For any 'text' or 'name' attribute in the request that is in a
      different natural language than the value supplied in the
      "attributes-natural-language" operation attribute, the Client MUST
      use the Natural Language Override mechanism (see Sections 5.1.2.2
      and 5.1.3.2) for each such attribute value supplied.  The Client
      MAY use the Natural Language Override mechanism redundantly, i.e.,
      use it even when the value is in the same natural language as the
      value supplied in the "attributes-natural-language" operation
      attribute of the request.

      The IPP object MUST accept any natural language and any Natural
      Language Override, whether the IPP object supports that natural
      language or not (and independent of the value of the
      "ipp-attribute-fidelity" operation attribute).  That is, the IPP
      object accepts all Client-supplied values no matter what the
      values are in the Printer's "generated-natural-language-supported"
      attribute.  That attribute,
      "generated-natural-language-supported", only applies to generated
      messages, not Client-supplied messages.  The IPP object MUST
      remember that natural language for all Client-supplied attributes,
      and when returning those attributes in response to a query, the
      IPP object MUST indicate that natural language.

      Each value whose attribute syntax type is 'text' or 'name' (see
      Sections 5.1.2 and 5.1.3) has an Associated Natural Language.
      This document does not specify how this association is stored in a
      Printer or Job object.  When such a value is encoded in a request
      or response, the natural language is either implicit or explicit:

      *  In the implicit case, the value contains only the text/name
         value, and the language is specified by the
         "attributes-natural-language" operation attribute in the
         request or response (see Sections 5.1.2.1 and 5.1.3.1).

      *  In the explicit case (also known as the Natural Language
         Override case), the value contains both the language and the
         text/name value (see Sections 5.1.2.2 and 5.1.3.2).




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      For example, the "job-name" attribute MAY be supplied by the
      Client in a Job Creation request.  The text value for this
      attribute will be in the natural language identified by the
      "attribute-natural-language" attribute, or if different, as
      identified by the Natural Language Override mechanism.  If
      supplied, the IPP object will use the value of the "job-name"
      attribute to populate the Job's "job-name" attribute.  Whenever
      any Client queries the Job's "job-name" attribute, the IPP object
      returns the attribute as stored and uses the Natural Language
      Override mechanism to specify the natural language, if it is
      different from that reported in the "attributes-natural-language"
      operation attribute of the response.  The IPP object MAY use the
      Natural Language Override mechanism redundantly, i.e., use it even
      when the value is in the same natural language as the value
      supplied in the "attributes-natural-language" operation attribute
      of the response.

      An IPP object MUST NOT reject a request based on a supplied
      natural language in an "attributes-natural-language" operation
      attribute or in any attribute that uses the Natural Language
      Override.

      Note: Supplying 'text' or 'name' attributes with an incompatible
      combination of natural language and charset can cause undesired
      behavior.  For example, suppose a Printer supports charsets
      'utf-8', 'iso-8859-1', and 'iso-8859-7'.  Suppose also that it
      supports natural languages 'en' (English), 'fr' (French), and 'el'
      (Greek).  Although the Printer supports the charset 'iso-8859-1'
      and natural language 'el', it probably does not support the
      combination of Greek text strings using the 'iso-8859-1' charset.
      The Printer handles this apparent incompatibility differently,
      depending on the context in which it occurs:

      *  In a Job Creation request: If the Client supplies a 'text' or
         'name' attribute (for example, the "job-name" operation
         attribute) that uses an apparently incompatible combination, it
         is a Client choice that does not affect the Printer or its
         correct operation.  Therefore, the Printer simply accepts the
         Client-supplied value, stores it with the Job, and responds
         back with the same combination whenever the Client (or any
         Client) queries for that attribute.

      *  In a query-type operation, like Get-Printer-Attributes: If the
         Client requests an apparently incompatible combination, the
         Printer responds (as described in Section 4.1.4.2) using the
         Printer's configured natural language rather than the natural
         language requested by the Client.




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      In either case, the Printer does not reject the request because of
      the apparent incompatibility.  The potential incompatible
      combination of charset and natural language can occur either at
      the global operation level or at the Natural Language Override
      attribute-by-attribute level.  In addition, since the response
      always includes explicit charset and natural language information,
      there is never any question or ambiguity in how the Client
      interprets the response.

4.1.4.2.  Response Operation Attributes

   The Printer MUST supply and the Client MUST support the following
   REQUIRED operation attributes in every IPP/1.1 operation response:

   "attributes-charset" (charset):

      This operation attribute identifies the charset used by any 'text'
      and 'name' attributes that the Printer object is returning in this
      response.  The value in this response MUST be the same value as
      the "attributes-charset" operation attribute supplied by the
      Client in the request.  If this is not possible (i.e., the charset
      requested is not supported), the request would have been rejected.
      See "attributes-charset" described in Section 4.1.4.1 above.

      If the Printer object supports more than just the 'utf-8' charset,
      the Printer object MUST be able to perform code conversion between
      each of the charsets supported on a "highest fidelity possible"
      basis in order to return the 'text' and 'name' attributes in the
      charset requested by the Client.  However, some information loss
      can occur during the charset conversion, depending on the charsets
      involved.  For example, depending on implementation, the Printer
      object can convert from a UTF-8 'a' to a US-ASCII 'a' (with no
      loss of information); from an ISO Latin 1 CAPITAL LETTER A WITH
      ACUTE ACCENT to US-ASCII 'A' (losing the accent); or from a UTF-8
      Japanese Kanji character to some ISO Latin 1 error character
      indication such as '?', a decimal code equivalent, or the absence
      of a character.

      Whether an implementation that supports more than one charset
      stores the data in the charset supplied by the Client or performs
      code conversion to one of the other supported charsets depends on
      implementation.  The strategy should try to minimize loss of
      information during code conversion.  On each response, such an
      implementation converts from its internal charset to that
      requested.






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   "attributes-natural-language" (naturalLanguage):

      This operation attribute identifies the natural language used by
      any 'text' and 'name' attributes that the IPP object is returning
      in this response.  Unlike the "attributes-charset" operation
      attribute, the IPP object MAY return the natural language of the
      Job object or the Printer's configured natural language as
      identified by the Printer's "natural-language-configured"
      attribute, rather than the natural language supplied by the
      Client.  For any 'text' or 'name' attribute or status message in
      the response that is in a different natural language than the
      value returned in the "attributes-natural-language" operation
      attribute, the IPP object MUST use the Natural Language Override
      mechanism (see Sections 5.1.2.2 and 5.1.3.2) on each attribute
      value returned.  The IPP object MAY use the Natural Language
      Override mechanism redundantly, i.e., use it even when the value
      is in the same natural language as the value supplied in the
      "attributes-natural-language" operation attribute of the response.

4.1.5.  Operation Targets

   All IPP operations are directed at IPP objects.  For Printer
   operations, the operation is always directed at a Printer object
   using one of its URIs, i.e., one of the values in the Printer's
   "printer-uri-supported" attribute.  Even if the Printer object
   supports more than one URI, the Client supplies only one URI as the
   target of the operation.  The Client identifies the target object by
   supplying the correct URI in the "printer-uri" operation attribute.

   For Job operations, the operation is directed at either:

   o  The Printer object that created the Job object using the Printer
      object's URI and the Job's numeric identifier (Job ID).  Since the
      Printer object that created the Job object generated the Job ID,
      it MUST be able to correctly associate the Client-supplied Job ID
      with the correct Job object.  The Client supplies the Printer's
      URI in the "printer-uri" operation attribute and the Job ID in the
      "job-id" operation attribute.

   o  The Job object itself using the Job's URI.  In this case, the
      Client identifies the target object by supplying the correct URI
      in the "job-uri" (uri) operation attribute (Section 5.3.2).

   Clients SHOULD send the "printer-uri" and "job-id" operation
   attributes in Job operations.






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   If the operation is directed at the Job object directly using the
   Job's URI, the Client MUST NOT include the redundant "job-id"
   operation attribute.

   The operation target attributes are REQUIRED operation attributes
   that are included in every operation request.  Like the charset and
   natural language attributes (see Section 4.1.4), the operation target
   attributes are specially ordered operation attributes.  In all cases,
   the operation target attributes immediately follow the
   "attributes-charset" and "attributes-natural-language" attributes
   within the Operation Attributes group; however, the specific ordering
   rules are as follows:

   o  In the case where there is only one operation target attribute
      (i.e., either only the "printer-uri" attribute or only the
      "job-uri" attribute), that attribute MUST be the third attribute
      in the Operation Attributes group.

   o  In the case where Job operations use two operation target
      attributes (i.e., the "printer-uri" and "job-id" attributes), the
      "printer-uri" attribute MUST be the third attribute and the
      "job-id" attribute MUST be the fourth attribute.

   In all cases, the target URIs contained within the body of IPP
   operation requests and responses MUST be in absolute format rather
   than relative format (a relative URL identifies a resource with the
   scope of the HTTP server, but does not include scheme, host,
   or port).

   The following rules apply to the use of port numbers in URIs that
   identify IPP objects:

   1.  If the URI scheme allows the port number to be explicitly
       included in the URI string, and a port number is specified within
       the URI, then that port number MUST be used by the Client to
       contact the IPP object.

   2.  If the URI scheme allows the port number to be explicitly
       included in the URI string, and a port number is not specified
       within the URI, then the default port number implied by that URI
       scheme MUST be used by the Client to contact the IPP object.

   3.  If the URI scheme does not allow an explicit port number to be
       specified within the URI, then the default port number implied by
       that URI MUST be used by the Client to contact the IPP object.






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   Note: "Internet Printing Protocol/1.1: IPP URL Scheme" [RFC3510] and
   "Internet Printing Protocol (IPP) over HTTPS Transport Binding and
   the 'ipps' URI Scheme" [RFC7472] define the mapping of IPP onto HTTP
   and HTTPS, respectively, and define and register a default port
   number.

4.1.6.  Operation Response Status-Code Values and Status Messages

   Every operation response includes a REQUIRED "status-code" parameter,
   SHOULD include the "status-message" operation attribute, and MAY
   include the "detailed-status-message" operation attribute.  The
   Print-URI and Send-URI response MAY also include the
   "document-access-error" operation attribute.

4.1.6.1.  "status-code" (type2 enum)

   The REQUIRED "status-code" parameter provides information on the
   processing of a request.

   The status-code is intended for use by automata.  A Client
   implementation of IPP SHOULD convert status-code values into any
   localized message that has semantic meaning to the End User.

   The "status-code" value is a numeric value that has semantic meaning.
   The "status-code" syntax is similar to a "type2 enum" (see
   Section 5.1 ("Attribute Syntaxes")), except that values can range
   only from 0x0000 to 0x7fff.  Appendix B describes and assigns the
   status-code values, and suggests a corresponding status message for
   each status-code for use by the Client when the user's natural
   language is English.

   If the Printer performs an operation with no errors and it encounters
   no problems, it MUST return the status-code 'successful-ok' in the
   response.  See Appendix B.

















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   If the Client supplies unsupported values for the following
   parameters or operation attributes, the Printer object MUST reject
   the operation, MAY return the unsupported attribute value in the
   Unsupported Attributes group, and MUST return the indicated
   status-code:

   +---------------------+---------------------------------------------+
   | Parameter/Attribute | Status-Code                                 |
   +---------------------+---------------------------------------------+
   | version-number      | server-error-version-not-supported          |
   +---------------------+---------------------------------------------+
   | operation-id        | server-error-operation-not-supported        |
   +---------------------+---------------------------------------------+
   | attributes-charset  | client-error-charset-not-supported          |
   +---------------------+---------------------------------------------+
   | compression         | client-error-compression-not-supported      |
   +---------------------+---------------------------------------------+
   | document-format     | client-error-document-format-not-supported  |
   +---------------------+---------------------------------------------+
   | document-uri        | client-error-uri-scheme-not-supported,      |
   |                     | client-error-document-access-error          |
   +---------------------+---------------------------------------------+

               Table 1: Status-Code Values for All Requests

   If the Client supplies unsupported values for other attributes, or
   unsupported attributes, the Printer returns the status-code defined
   in Section 4.1.7 ("Unsupported Attributes").

4.1.6.2.  "status-message" (text(255))

   The RECOMMENDED "status-message" operation attribute provides a short
   textual description of the status of the operation.  The
   "status-message" attribute's syntax is "text(255)", so the maximum
   length is 255 octets (see Section 5.1.2).  The status message is
   intended for the human End User.  If a response does include a
   "status-message" attribute, an IPP Client can examine or display the
   messages in some implementation-specific manner.  The
   "status-message" attribute is especially useful for a later version
   of a Printer to return as supplemental information for the human
   user, to accompany a status-code that an earlier version of a Client
   might not understand.

   If the Printer supports the "status-message" operation attribute, it
   MUST be able to generate this message in any of the natural languages
   identified by the Printer's "generated-natural-language-supported"
   attribute and MUST honor any supported value for the
   "attributes-natural-language" operation attribute (Section 4.1.4.1)



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   of the Client request.  Appendix B suggests the text for the status
   message returned by the Printer for use with the English natural
   language.

   As described in Section 4.1.4.1, for any returned 'text' attribute,
   if there is a choice for generating this message, the Printer uses
   the natural language indicated by the value of
   "attributes-natural-language" in the Client request, if supported;
   otherwise, the Printer uses the value in the Printer's own
   "natural-language-configured" attribute.

   If the Printer supports the "status-message" operation attribute, it
   SHOULD use the REQUIRED 'utf-8' charset to return a status message
   for the following error status-code values (see Appendix B):
   'client-error-bad-request', 'client-error-charset-not-supported',
   'server-error-internal-error',
   'server-error-operation-not-supported', and
   'server-error-version-not-supported'.  In this case, it MUST set the
   value of the "attributes-charset" operation attribute to 'utf-8' in
   the error response.

4.1.6.3.  "detailed-status-message" (text(MAX))

   The OPTIONAL "detailed-status-message" operation attribute provides
   additional more-detailed technical and implementation-specific
   information about the operation for Administrators or other
   experienced technical people.  The "detailed-status-message"
   attribute's syntax is "text(MAX)", so the maximum length is
   1023 octets (see Section 5.1.2).  If the Printer supports the
   "detailed-status-message" operation attribute, the Printer SHOULD
   localize the message, unless such localization would obscure the
   technical meaning of the message.  Clients MUST NOT attempt to parse
   the value of this attribute.  See the "document-access-error"
   operation attribute (Section 4.1.6.4) for additional errors that a
   program can process.

4.1.6.4.  "document-access-error" (text(MAX))

   This OPTIONAL operation attribute provides additional information
   about any Document access errors encountered by the Printer before it
   returned a response to the Print-URI (Section 4.2.2) or Send-URI
   (Section 4.3.2) operation.  For errors in the protocol identified by
   the URI scheme in the "document-uri" operation attribute, such as
   'http:' or 'ftp:', the error code is returned in parentheses,
   followed by the URI.  For example:

   (404) http://www.example.com/filename.pdf




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   Most Internet protocols use decimal error codes (unlike IPP), so the
   ASCII error code representation is in decimal.

4.1.7.  Unsupported Attributes

   The Unsupported Attributes group contains attributes that are not
   supported by the operation.  This group is primarily for the Job
   Creation operations, but all operations can return this group.

   A Printer MUST include an Unsupported Attributes group in a response
   if the status-code is one of the following:
   'successful-ok-ignored-or-substituted-attributes',
   'successful-ok-conflicting-attributes',
   'client-error-attributes-or-values-not-supported', or
   'client-error-conflicting-attributes'.

   If the status-code is one of the four specified in the preceding
   paragraph, the Unsupported Attributes group MUST contain all of those
   attributes and only those attributes that are:

   a.  an operation or Job Template attribute supplied in the request,
       and

   b.  unsupported by the Printer.  See below for details on the three
       categories of "unsupported" attributes.

   If the status-code is one of those in Table 1 in Section 4.1.6.1, the
   OPTIONAL Unsupported Attributes group contains the unsupported
   parameter or attribute indicated in that table.

   If the Printer is not returning any unsupported attributes in the
   response, the Printer SHOULD omit the Unsupported Attributes group
   rather than sending an empty group.  However, a Client MUST be able
   to accept an empty group.

   Unsupported attributes fall into three categories:

   1.  The Printer does not support the supplied attribute (no matter
       what the attribute syntax or value).

   2.  The Printer does support the attribute, but it does not support
       some or all of the particular attribute syntaxes or values
       supplied by the Client, i.e., the Printer does not have those
       attribute syntaxes or values in its corresponding "xxx-supported"
       attribute.






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   3.  The Printer does support the attributes and values supplied, but
       the particular values are in conflict with one another, because
       they violate a constraint, such as not being able to staple
       transparencies.

   In the case of an unsupported attribute name, the Printer returns the
   Client-supplied attribute with a substituted value of 'unsupported'.
   This value's syntax type is "out-of-band", and its encoding is
   defined by special rules for "out-of-band" values in the Encoding and
   Transport document [RFC8010].  Its value indicates no support for the
   attribute itself -- see the beginning of Section 5.1 in this
   document.

   In the case of a supported attribute with one or more unsupported
   attribute syntaxes or values, the Printer simply returns the
   Client-supplied attribute with the unsupported attribute syntaxes or
   values as supplied by the Client.  This indicates support for the
   attribute but no support for that particular attribute syntax or
   value.  If the Client supplies a multi-valued attribute with more
   than one value and the Printer supports the attribute but only
   supports a subset of the Client-supplied attribute syntaxes or
   values, the Printer MUST return only those attribute syntaxes or
   values that are unsupported.

   In the case of two (or more) supported attribute values that are in
   conflict with one another (although each is supported independently,
   the values conflict when requested together within the same Job), the
   Printer MUST return all the values that it ignores or substitutes to
   resolve the conflict but not any of the values that it is still
   using.  The choice for exactly how to resolve the conflict is
   implementation dependent.  See Section 4.2.1.2 and Appendix C.  See
   the Implementor's Guides [RFC3196] [PWG5100.19] for examples.

4.1.8.  Versions

   Each operation request and response carries with it a
   "version-number" parameter.  Each value of the "version-number"
   parameter is in the form "X.Y" where X is the major version number
   and Y is the minor version number.  By including a version number in
   the Client request, it allows the Client to identify which version of
   IPP it is interested in using, i.e., the version whose conformance
   requirements the Client can depend upon the Printer to meet.

   If the IPP object does not support that major version number supplied
   by the Client, i.e., the "major version number" portion of the
   "version-number" parameter does not match any of the values of the
   Printer's "ipp-versions-supported" attribute (see Section 5.4.14),
   the object MUST respond with a status-code of



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   'server-error-version-not-supported' along with the closest version
   number that is supported (see Appendix B.1.5.4).  If the major
   version number is supported but the minor version number is not, the
   IPP object SHOULD accept the request and attempt to perform it (or
   reject the request if the operation is not supported); otherwise, it
   rejects the request and returns the
   'server-error-version-not-supported' status-code.  In all cases, the
   IPP object MUST return the "version-number" value that it supports
   that is closest to the version number supplied by the Client in the
   request.

   There is no version negotiation per se.  However, if a Client has
   received a 'server-error-version-not-supported' status-code from an
   IPP object, the Client SHOULD try again with a different version
   number.  A Client MAY also determine the versions supported either
   from a directory that conforms to Appendix D or by querying the
   Printer's "ipp-versions-supported" attribute (see Section 5.4.14) to
   determine which versions are supported.

   An IPP/1.1 object implementation MUST support version '1.1', i.e.,
   meet the conformance requirements for IPP/1.1 as specified in this
   document and [RFC8010].  IPP implementations SHOULD accept any
   request with the major version '1' or '2', or reject the request if
   the operation is not supported.

   There is only one notion of "version number" that covers both IPP
   Model and IPP protocol changes.  Changes to the major version number
   of the Model and Semantics document can indicate structural or
   syntactic changes that make it impossible for older versions of IPP
   Clients and Printers to correctly parse and correctly process the new
   or changed attributes, operations, and responses.  If the major
   version number changes, the minor version number is set to zero.  As
   an example, adding the REQUIRED "ipp-attribute-fidelity" attribute to
   version '1.1' (if it had not been part of version '1.0') would have
   required a change to the major version number, since an IPP/1.0
   Printer would not have processed a request with the correct semantics
   that contained the "ipp-attribute-fidelity" attribute that it did not
   know about.  Items that might affect the changing of the major
   version number include any changes to the Model and Semantics
   document (this document) or the Encoding and Transport document
   [RFC8010] itself, such as:

   o  reordering of ordered attributes or attribute sets

   o  changes to the syntax of existing attributes

   o  adding REQUIRED (for an IPP object to support) Operation
      Attributes groups



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   o  adding values to existing REQUIRED operation attributes

   o  adding REQUIRED operations

   Changes to the minor version number indicate the addition of new
   features, attributes, and attribute values that might not be
   understood by all IPP objects but that can be ignored if not
   understood.  Items that might affect the changing of the minor
   version number include any changes to the model objects and
   attributes but not the encoding and transport rules [RFC8010] (except
   adding attribute syntaxes).  Examples of such changes are:

   o  grouping all extensions not included in a previous version into a
      new version

   o  adding new attribute values

   o  adding new object attributes

   o  adding OPTIONAL (for an IPP object to support) operation
      attributes (i.e., those attributes that an IPP object can ignore
      without confusing Clients)

   o  adding OPTIONAL (for an IPP object to support) Operation
      Attributes groups (i.e., those attributes that an IPP object can
      ignore without confusing Clients)

   o  adding new attribute syntaxes

   o  adding OPTIONAL operations

   o  changing Job attributes or Printer attributes from OPTIONAL to
      REQUIRED or vice versa

   o  adding OPTIONAL attribute syntaxes to an existing attribute

   The encoding [RFC8010] of the "version-number" parameter MUST NOT
   change over any version number (either major or minor).  This rule
   guarantees that all future versions will be backwards compatible with
   all previous versions (at least for checking the "version-number"
   parameter).  In addition, any protocol elements (attributes, error
   codes, tags, etc.) that are not carried forward from one version to
   the next are DEPRECATED so that they can never be reused with new
   semantics.







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   Implementations that support a certain version SHOULD support all
   previous Standards Track versions.  As each new version is defined
   (through the release of a new IPP specification document), that
   version will specify which previous versions MUST and which versions
   SHOULD be supported in compliant implementations.

4.1.9.  Job Creation Operations

   In order to "submit a Print Job" and create a new Job, a Client
   issues a Job Creation request.  A Job Creation request is any one of
   the following three operation requests:

   o  The Print-Job Request: A Client that wants to submit a Print Job
      with only a single Document can use the Print-Job operation.  The
      operation allows for the Client to "push" the Document data to the
      Printer by including the Document data in the request itself.
      Note that Clients SHOULD instead use the Create-Job and
      Send-Document requests, if supported by the Printer, since they
      allow for Job monitoring and control during submission of the
      Document data.

   o  The Print-URI Request: A Client that wants to submit a Print Job
      with only a single Document (where the Printer "pulls" the
      Document data instead of the Client "pushing" the data to the
      Printer) uses the Print-URI operation.  In this case, the Client
      includes in the request only a URI reference to the Document data
      (not the Document data itself).

   o  The Create-Job Request: A Client that wants to submit a Print Job
      with zero or more Documents uses the Create-Job operation.  This
      operation is followed by an arbitrary number of Send-Document
      and/or Send-URI operations, each creating another Document for the
      newly created Job.  The Send-Document operation includes the
      Document data in the request (the Client "pushes" the Document
      data to the Printer), and the Send-URI operation includes only a
      URI reference to the Document data in the request (the Printer
      "pulls" the Document data from the referenced location).  The last
      Send-Document or Send-URI request for a given Job includes a
      "last-document" operation attribute set to 'true' indicating that
      this is the last request.

   Throughout this document, the term "Job Creation request" is used to
   refer to any of these three operation requests.

   A Create-Job operation followed by only one Send-Document operation
   is semantically equivalent to a Print-Job operation; however, the
   Client SHOULD use the Create-Job and Send-Document operations (when
   supported) for all Jobs with a single Document to allow for reliable



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   Job control and monitoring.  Print-Job is a REQUIRED operation (all
   implementations MUST support it), whereas Create-Job is a RECOMMENDED
   operation and hence some implementations might not support it.

   Job submission time is the point in time when a Client issues a Job
   Creation request.  The initial state of every Job is the 'pending',
   'pending-held', or 'processing' state (see Section 5.3.7).  When the
   Printer begins processing the Print Job, the Job's state moves to
   'processing'.  This is known as Job processing time.

   At Job submission time and at the time a Validate-Job operation is
   received, the Printer MUST do the following:

   1.  Process the Client-supplied attributes and either accept or
       reject the request

   2.  Validate the syntax of and support for the scheme of any
       Client-supplied URI

   At Job submission time, the Printer MUST validate whether the
   supplied attributes, attribute syntaxes, and values are supported by
   matching them with the Printer's corresponding "xxx-supported"
   attributes.  See Section 4.1.7 for details.  See the Implementor's
   Guides [RFC3196] [PWG5100.19] for guidance on processing Job Creation
   requests.

   At Job submission time, the Printer MAY perform the validation checks
   reserved for Job processing time, such as:

   1.  Validating the format of the Document data

   2.  Validating the actual contents of any Client-supplied URI
       (resolve the reference and follow the link to the Document data)

   At Job submission time, these additional Job processing time
   validation checks are essentially useless, since they require
   actually parsing and interpreting the Document data, are not
   guaranteed to be 100% accurate, and MUST be done, yet again, at Job
   processing time.  Also, in the case of a URI, checking for
   availability at Job submission time does not guarantee availability
   at Job processing time.  In addition, at Job processing time, the
   Printer might discover any of the following conditions that were not
   detectable at Job submission time:

   o  runtime errors in the Document data,

   o  nested Document data that is in an unsupported format,




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   o  the URI reference is no longer valid (i.e., the server hosting the
      Document might be down), or

   o  any other Job processing error.

   At Job submission time, a Printer, especially a non-spooling Printer,
   MAY accept Jobs for which it does not have enough space.  In such a
   situation, a Printer MAY stop reading data from a Client for an
   indefinite period of time.  A Client MUST be prepared for a write
   operation to block for an indefinite period of time (see Section 6.1
   ("Client Conformance Requirements")).

   When a Printer has too little space for starting a new Job, it MAY
   reject a new Job Creation request.  In this case, a Printer MUST
   return a response (in reply to the rejected request) with a
   status-code of 'server-error-busy' (see Appendix B.1.5.8), and it MAY
   close the connection before receiving all bytes of the operation.  A
   Printer SHOULD indicate that it is temporarily unable to accept Jobs
   by setting the 'spool-space-full' value in its
   "printer-state-reasons" attribute and removing the value when it can
   accept another Job (see Section 5.4.12).

   When receiving a 'server-error-busy' status-code in an operation
   response, a Client MUST be prepared for the Printer to close the
   connection before the Client has sent all of the data (especially for
   the Print-Job operation).  A Client MUST be prepared to keep
   submitting a Job Creation request until the Printer accepts the Job
   Creation request.

   At Job processing time, since the Printer has already responded with
   a successful status-code in the response to the Job Creation request,
   if the Printer detects an error, the Printer is unable to inform the
   End User of the error with an operation status-code.  In this case,
   the Printer, depending on the error, can set the Job's "job-state",
   "job-state-reasons", and/or "job-state-message" attributes to the
   appropriate value(s) so that later queries can report the correct Job
   status.

   Note: Asynchronous notification of events is defined in "Internet
   Printing Protocol (IPP): Event Notifications and Subscriptions"
   [RFC3995].

4.2.  Printer Operations

   All Printer operations are directed at Printers.  A Client MUST
   always supply the "printer-uri" operation attribute in order to
   identify the correct target of the operation.




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4.2.1.  Print-Job Operation

   This REQUIRED operation allows a Client to submit a Print Job with
   only one Document and supply the Document data (rather than just a
   reference to the data).  See Appendix C for the suggested steps for
   processing Job Creation requests and their operation and Job Template
   attributes.

4.2.1.1.  Print-Job Request

   The following groups of attributes are supplied as part of the
   Print-Job request:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.  The Printer MUST
         copy these values to the corresponding Job Status attributes
         described in Sections 5.3.19 and 5.3.20.

      Target:

         The "printer-uri" (uri) operation attribute, which is the
         target for this operation as described in Section 4.1.5.

      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.

      "job-name" (name(MAX)):

         The Client MAY supply and the Printer MUST support this
         attribute.  It contains the Client-supplied Job name.  If this
         attribute is supplied by the Client, its value is used for the
         "job-name" attribute of the newly created Job.  The Client MAY
         automatically include any information that will help the
         End User distinguish amongst his/her Jobs, such as the name of
         the application program along with information from the
         Document, such as the Document name, Document subject, or
         source file name.  If this attribute is not supplied by the
         Client, the Printer generates a name to use in the "job-name"
         attribute of the newly created Job (see Section 5.3.5).






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      "ipp-attribute-fidelity" (boolean):

         The Client MAY supply and the Printer MUST support this
         attribute.  The value 'true' indicates that total fidelity to
         Client-supplied Job Template attributes and values is required;
         otherwise, the Printer MUST reject the Print-Job request.  The
         value 'false' indicates that a reasonable attempt to print the
         Job is acceptable and the Printer MUST accept the Print-Job
         request.  If not supplied, the Printer assumes that the value
         is 'false'.  All Printers MUST support both types of Job
         processing.  See Appendix C for a full description of
         "ipp-attribute-fidelity" and its relationship to other
         attributes, especially the Printer's "pdl-override-supported"
         attribute.

      "document-name" (name(MAX)):

         The Client MAY supply and the Printer MUST support this
         attribute.  It contains the Client-supplied Document name.  The
         Document name MAY be different than the Job name.  Typically,
         the Client software automatically supplies the Document name on
         behalf of the End User by using a file name or an
         application-generated name.  If this attribute is supplied, its
         value can be used in a manner defined by each implementation.
         Examples include the following: printed along with the Job (Job
         start sheet, page adornments, etc.), used by accounting or
         resource-tracking management tools, or even stored along with
         the Document as a Document-level attribute.

      "compression" (type2 keyword):

         The Client MAY supply and the Printer MUST support this
         attribute.  The Client-supplied "compression" operation
         attribute identifies the compression algorithm used on the
         Document data.  The following cases exist:

         a.  If the Client omits this attribute, the Printer MUST assume
             that the data is not compressed, i.e., the Printer follows
             the rules below as if the Client supplied the "compression"
             attribute with a value of 'none'.

         b.  If the Client supplies this attribute but the value is not
             supported by the Printer, i.e., the value is not one of the
             values of the Printer's "compression-supported" attribute,
             the Printer MUST reject the request and return the
             'client-error-compression-not-supported' status-code.  See
             Section 4.1.7 for details on returning unsupported
             attributes and values.



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         c.  If the Client supplies the attribute and the Printer
             supports the attribute value, the Printer uses the
             corresponding decompression algorithm on the Document data.

         d.  If the decompression algorithm fails before the Printer
             returns an operation response, the Printer MUST reject the
             request and return the 'client-error-compression-error'
             status-code.

         e.  If the decompression algorithm fails after the Printer
             returns an operation response, the Printer MUST abort the
             Job and add the 'compression-error' value to the Job's
             "job-state-reasons" attribute.

         f.  If the decompression algorithm succeeds, the Document data
             MUST then have the format specified by the Job's
             "document-format" attribute, if supplied (see the
             "document-format" operation attribute definition below).

      "document-format" (mimeMediaType):

         The Client MAY supply and the Printer MUST support this
         attribute.  The value identifies the format of the supplied
         Document data.  The following cases exist:

         a.  If the Client does not supply this attribute, the Printer
             assumes that the Document data is in the format defined by
             the Printer's "document-format-default" attribute (i.e.,
             the Printer follows the rules below as if the Client
             supplied the "document-format" attribute with a value equal
             to the Printer's default value).

         b.  If the Client supplies this attribute but the value is not
             supported by the Printer, i.e., the value is not one of the
             values of the Printer's "document-format-supported"
             attribute, the Printer MUST reject the request and return
             the 'client-error-document-format-not-supported'
             status-code.

         c.  If the Client supplies this attribute and its value is
             'application/octet-stream' (i.e., to be auto-sensed; see
             Section 5.1.10.1), and the format is not one of the
             Document formats that the Printer can auto-sense, and this
             check occurs before the Printer returns an operation
             response, then the Printer MUST reject the request and
             return the 'client-error-document-format-not-supported'
             status-code.




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         d.  If the Client supplies this attribute and the value is
             supported by the Printer, the Printer is capable of
             interpreting the Document data.

         e.  If interpretation of the Document data fails before the
             Printer returns an operation response, the Printer MUST
             reject the request and return the
             'client-error-document-format-error' status-code.

         f.  If interpretation of the Document data fails after the
             Printer returns an operation response, the Printer MUST
             abort the Job and add the 'document-format-error' value to
             the Job's "job-state-reasons" attribute.

      "document-natural-language" (naturalLanguage):

         The Client MAY supply and the Printer SHOULD support this
         attribute.  The value specifies the natural language of the
         Document content for those Document formats that require a
         specification of the natural language in order to properly
         image the Document.

      "job-k-octets" (integer(0:MAX)):

         The Client MAY supply and the Printer SHOULD support this
         attribute.  The Client-supplied "job-k-octets" operation
         attribute identifies the total size of the Document(s) in
         K octets being submitted (see Section 5.3.17.1 for the complete
         semantics).  If the Client supplies the attribute and the
         Printer supports the attribute, the value of the attribute is
         used to populate the Job's "job-k-octets" Job Description
         attribute.

         For this attribute and the following two attributes
         ("job-impressions" and "job-media-sheets"), if the Client
         supplies the attribute but the Printer does not support the
         attribute, the Printer ignores the Client-supplied value.  If
         the Client supplies the attribute and the Printer supports the
         attribute, and the value is within the range of the
         corresponding Printer's "xxx-supported" attribute, the Printer
         MUST use the value to populate the Job's "xxx" attribute.  If
         the Client supplies the attribute and the Printer supports the
         attribute, but the value is outside the range of the
         corresponding Printer's "xxx-supported" attribute, the Printer
         MUST copy the attribute and its value to the Unsupported
         Attributes group, reject the request, and return the
         'client-error-attributes-or-values-not-supported' status-code.
         If the Client does not supply the attribute, the Printer SHOULD



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         populate the corresponding Job attribute if it supports the
         attribute and is able to calculate or discern the correct
         value.

      "job-impressions" (integer(0:MAX)):

         The Client MAY supply and the Printer SHOULD support this
         attribute.  The Client-supplied "job-impressions" operation
         attribute identifies the total size in number of Impressions of
         the Document(s) being submitted (see Section 5.3.17.2 for the
         complete semantics).

         See the last paragraph under "job-k-octets".

      "job-media-sheets" (integer(1:MAX)):

         The Client MAY supply and the Printer SHOULD support this
         attribute.  The Client-supplied "job-media-sheets" operation
         attribute identifies the total number of Media Sheets to be
         produced for this Job (see Section 5.3.17.3 for the complete
         semantics).

         See the last paragraph under "job-k-octets".

   Group 2: Job Template Attributes

      The Client MAY supply a set of Job Template attributes as defined
      in Section 5.2.  If the Client is not supplying any Job Template
      attributes in the request, the Client SHOULD omit Group 2 rather
      than sending an empty group.  However, a Printer MUST be able to
      accept an empty group.

   Group 3: Document Data

      The Client MUST supply the Document data to be processed.

   The simplest Print-Job request consists of just the
   "attributes-charset" and "attributes-natural-language" operation
   attributes, the "printer-uri" target operation attribute, and the
   Document data.  In this simple case, the Printer:

   o  creates a new Job containing a single Document,

   o  stores a generated Job name in the "job-name" attribute in the
      natural language and charset requested (see Section 4.1.4.1) (if
      those are supported; otherwise, using the Printer's default
      natural language and charset), and




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   o  at Job processing time, uses its corresponding default value
      attributes for the supported Job Template attributes that were not
      supplied by the Client as an IPP attribute or embedded
      instructions in the Document data.

4.2.1.2.  Print-Job Response

   The Printer MUST return to the Client the following sets of
   attributes as part of the Print-Job response:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.  If the Client supplies unsupported or
         conflicting Job Template attributes or values, the Printer MUST
         reject or accept the Print-Job request, depending on whether
         the Client supplied a 'true' or 'false' value for the
         "ipp-attribute-fidelity" operation attribute.  See the
         Implementor's Guides [RFC3196] [PWG5100.19] for guidance on
         processing Job Creation requests.

   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.

      The value of "ipp-attribute-fidelity" supplied by the Client does
      not affect what attributes the Printer returns in this group.  The
      value of "ipp-attribute-fidelity" only affects whether the
      Print-Job operation is accepted or rejected.  If the Job is
      accepted, the Client can query the Job using the
      Get-Job-Attributes operation, requesting the unsupported
      attributes that were returned in the Print-Job response to see
      which attributes were ignored (not stored in the Job) and which
      attributes were stored with other (substituted) values.







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   Group 3: Job Attributes

      "job-id" (integer(1:MAX)):

         The Printer MUST return the Job's ID in the REQUIRED "job-id"
         Job attribute.  The Client uses this "job-id" attribute in
         conjunction with the "printer-uri" attribute used in the
         Print-Job request when directing Job operations at the Printer.

      "job-uri" (uri):

         The Printer MUST return the Job's URI by returning the contents
         of the REQUIRED "job-uri" Job attribute.

      "job-state" (type1 enum):

         The Printer MUST return the Job's REQUIRED "job-state"
         attribute.  The value of this attribute along with the value of
         the "job-state-reasons" attribute is a "snapshot" of the new
         Job's state when the Printer returns the response.

      "job-state-reasons" (1setOf type2 keyword):

         The Printer MUST return the Job's REQUIRED "job-state-reasons"
         attribute.

      "job-state-message" (text(MAX)):

         The Printer SHOULD return the Job's RECOMMENDED
         "job-state-message" attribute.  If the Printer supports this
         attribute, then it MUST be returned in the response.  If this
         attribute is not returned in the response, the Client can
         assume that the "job-state-message" attribute is not supported
         and will not be returned in a subsequent Job query.

      "number-of-intervening-jobs" (integer(0:MAX)):

         The Printer SHOULD return the Job's RECOMMENDED
         "number-of-intervening-jobs" attribute.  If the Printer
         supports this attribute, then it MUST be returned in the
         response.  If this attribute is not returned in the response,
         the Client can assume that the "number-of-intervening-jobs"
         attribute is not supported and will not be returned in a
         subsequent Job query.







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   Note: Since any Printer state information that affects a Job's state
   is reflected in the "job-state" and "job-state-reasons" attributes,
   it is sufficient to return only these attributes and no additional
   Printer Status attributes.

   Note: The simplest response consists of just the "attributes-charset"
   and "attributes-natural-language" operation attributes and the
   "job-uri", "job-id", and "job-state" Job attributes.  In this
   simplest case, the status-code is 'successful-ok' and there is no
   "status-message" or "detailed-status-message" operation attribute.

4.2.2.  Print-URI Operation

   This OPTIONAL operation is identical to the Print-Job operation
   (Section 4.2.1), except that a Client supplies a URI reference to the
   Document data using the "document-uri" (uri) operation attribute (in
   Group 1) rather than including the Document data itself.  Before
   returning the response, the Printer MUST validate that the Printer
   supports the retrieval method (e.g., 'http', 'ftp', etc.) implied by
   the URI and MUST check for valid URI syntax.  If the Client-supplied
   URI scheme is not supported, i.e., the value is not in the Printer's
   "referenced-uri-scheme-supported" attribute, the Printer MUST reject
   the request and return the 'client-error-uri-scheme-not-supported'
   status-code.

   The Printer MAY validate the accessibility of the Document as part of
   the operation, or subsequently.  If the Printer discovers an
   accessibility problem before returning an operation response, it MUST
   reject the request and return the
   'client-error-document-access-error' status-code.  The Printer MAY
   also return a specific Document access error code using the
   "document-access-error" operation attribute (see Section 4.1.6.4).

   If the Printer discovers this Document accessibility problem after
   accepting the request and returning an operation response with one of
   the successful status-code values, the Printer MUST add the
   "document-access-error" value to the Job's "job-state-reasons"
   attribute and MAY populate the Job's "job-document-access-errors" Job
   Status attribute (see Section 5.3.11).  See the Implementor's Guides
   [RFC3196] [PWG5100.19] for guidance on processing Job Creation
   requests.

   If the Printer supports this operation, it MUST support the
   "reference-uri-schemes-supported" Printer attribute (see
   Section 5.4.27).

   It is up to the Printer to interpret the URI and subsequently "pull"
   the Document data from the source referenced by the URI string.



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4.2.3.  Validate-Job Operation

   This REQUIRED operation is similar to the Print-Job operation
   (Section 4.2.1), except that a Client supplies no Document data and
   the Printer allocates no resources, i.e., it does not create a new
   Job.  This operation is used only to verify the capabilities of a
   Printer against whatever attributes are supplied by the Client in the
   Validate-Job request.  By using the Validate-Job operation, a Client
   can validate that an identical Job Creation request (with the
   Document data) would be accepted.  The Validate-Job operation also
   performs the same security negotiation as the Print-Job, Print-URI,
   and Create-Job operations (see Section 9) so that a Client can check
   that the Client and Printer security requirements can be met before
   performing a Job Creation request.

   The Validate-Job operation does not accept a "document-uri" attribute
   in order to allow a Client to check that the same Print-URI operation
   will be accepted, since the Client doesn't send the data with the
   Print-URI operation.  The Client SHOULD just issue the Print-URI
   request.

   The Printer returns the same status-code values, Operation Attributes
   (Group 1), and Unsupported Attributes (Group 2) as the Print-Job
   operation.  However, no Job Attributes (Group 3) are returned, since
   no Job is created.

4.2.4.  Create-Job Operation

   This RECOMMENDED operation is similar to the Print-Job operation
   (Section 4.2.1), except that in the Create-Job request, a Client does
   not supply Document data or any reference to Document data.  Also,
   the Client does not supply any of the "document-name",
   "document-format", "compression", or "document-natural-language"
   operation attributes.  This operation is followed by one or more
   Send-Document or Send-URI operations.  In each of those operation
   requests, the Client MAY supply the "document-name",
   "document-format", and "document-natural-language" attributes for
   each Document in the Job.

   If a Printer supports the Create-Job operation, it MUST also support
   the Send-Document operation.  If the Printer supports the Create-Job
   and Print-URI operations, it MUST also support the Send-URI
   operation.

   If the Printer supports this operation, it MUST support the
   "multiple-operation-time-out" Printer attribute (see Section 5.4.31).





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   If the Printer supports this operation, then it MUST support the
   "multiple-document-jobs-supported" Printer Description attribute
   (see Section 5.4.16) and indicate whether it supports multiple
   Documents in a Job.

   If the Printer supports this operation and supports multiple
   Documents in a Job, then it MUST support the
   "multiple-document-handling" Job Template attribute with at least
   one value (see Section 5.2.4), and the associated
   "multiple-document-handling-default" and
   "multiple-document-handling-supported" Printer attributes
   (see Section 5.2).

   After the Create-Job operation has completed, the value of the
   "job-state" attribute is similar to the "job-state" after a Print-Job
   operation, even though no Document data has arrived.  A Printer MAY
   set the 'job-data-insufficient' value of the Job's
   "job-state-reasons" attribute to indicate that processing cannot
   begin until sufficient data has arrived and set the "job-state" to
   either 'pending' or 'pending-held'.  A non-spooling Printer that
   doesn't implement the 'pending' Job state can set "job-state" to
   'processing', even though there is not yet any data to process.
   See Sections 5.3.7 and 5.3.8.

4.2.5.  Get-Printer-Attributes Operation

   This REQUIRED operation allows a Client to request the values of the
   attributes of a Printer.  In the request, the Client supplies the set
   of Printer attribute names and/or attribute group names in which the
   requester is interested.  In the response, the Printer returns a
   corresponding attribute set with the appropriate attribute values
   filled in.

   For Printers, the possible names of attribute groups are:

   o  'job-template': the subset of the Job Template attributes that
      apply to a Printer (the last two columns of Table 8 in
      Section 5.2) that the implementation supports for Printers.

   o  'printer-description': the subset of the attributes specified in
      Section 5.4 that the implementation supports for Printers.

   o  'all': the special group 'all' that includes all attributes that
      the implementation supports for Printers.

   Since a Client MAY request specific attributes or named groups, there
   is a potential for some overlap.  For example, if a Client requests
   'printer-name' and 'all', the Client is actually requesting the



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   "printer-name" attribute twice: once by naming it explicitly, and
   once by inclusion in the 'all' group.  In such cases, the Printer
   returns each attribute only once in the response even if it is
   requested multiple times.  The Client SHOULD NOT request the same
   attribute in multiple ways.

   Printers MUST support all group names and MUST return all supported
   attributes belonging to the group.

4.2.5.1.  Get-Printer-Attributes Request

   The following sets of attributes are part of the
   Get-Printer-Attributes request:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.

      Target:

         The "printer-uri" (uri) operation attribute, which is the
         target for this operation as described in Section 4.1.5.

      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.

      "requested-attributes" (1setOf keyword):

         The Client MAY supply a set of attribute names and/or attribute
         group names in whose values the requester is interested.  The
         Printer MUST support this attribute.  If the Client omits this
         attribute, the Printer MUST respond as if this attribute had
         been supplied with a value of 'all'.

      "document-format" (mimeMediaType):

         The Client MAY supply and the Printer MUST support this
         attribute.  It is useful for a Client to determine the set of
         supported attribute values that relate to the requested
         Document format.  The Printer MUST return the attributes and
         values that it uses to validate a Job in a Job Creation or
         Validate-Job operation in which this Document format is
         supplied.  The Printer SHOULD return only (1) those attributes



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         that are supported for the specified format and (2) the
         attribute values that are supported for the specified Document
         format.  By specifying the Document format, the Client can get
         the Printer to eliminate the attributes and values that are not
         supported for a specific Document format.  For example, a
         Printer might have multiple interpreters to support both
         'application/postscript' (for PostScript) and 'text/plain' (for
         text) Documents.  However, only one of those interpreters might
         support the "number-up" Job Template attribute with values of
         '1', '2', and '4'.  The other interpreter might only be able to
         support the "number-up" Job Template attribute with a value of
         '1'.  Thus, a Client can use the Get-Printer-Attributes
         operation to obtain the attributes and values that will be used
         to accept/reject a Job Creation request.

         If the Printer does not distinguish between different sets of
         supported values for each different Document format when
         validating Jobs in the Create-Job, Print-Job, Print-URI, and
         Validate-Job operations, it MUST NOT distinguish between
         different Document formats in the Get-Printer-Attributes
         operation.  If the Printer does distinguish between different
         sets of supported values for each different Document format
         specified by the Client, this specialization applies only to
         the following Printer attributes:

         +  Printer attributes that are Job Template attributes
            ("xxx-default", "xxx-supported", and "xxx-ready")
            (see Table 8 in Section 5.2),

         +  "pdl-override-supported",

         +  "compression-supported",

         +  "job-k-octets-supported",

         +  "job-impressions-supported,

         +  "job-media-sheets-supported",

         +  "printer-driver-installer",

         +  "color-supported", and

         +  "reference-uri-schemes-supported"







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         The values of all other Printer attributes (including
         "document-format-supported") remain invariant with respect to
         the Client-supplied Document format (except for new Printer
         Description attributes as registered according to Section 7.2).

         If the Client omits this "document-format" operation attribute,
         the Printer MUST respond as if the attribute had been supplied
         with the value of the Printer's "document-format-default"
         attribute.  Clients SHOULD always supply a value for
         "document-format", since the Printer's
         "document-format-default" value can be
         'application/octet-stream', in which case the returned
         attributes and values are for the union of the Document formats
         that the Printer can automatically sense.  For more details,
         see the description of the 'mimeMediaType' attribute syntax in
         Section 5.1.10.

         If the Client supplies a value for the "document-format"
         operation attribute that is not supported by the Printer, i.e.,
         is not among the values of the Printer's
         "document-format-supported" attribute, the Printer MUST reject
         the operation and return the
         'client-error-document-format-not-supported' status-code.

4.2.5.2.  Get-Printer-Attributes Response

   The Printer returns the following sets of attributes as part of the
   Get-Printer-Attributes response:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.








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   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.

      The response MAY contain the "requested-attributes" operation
      attribute with any supplied values (attribute keywords) that were
      requested by the Client but are not supported by the Printer.  If
      the Printer does return unsupported attributes referenced in the
      "requested-attributes" operation attribute and that attribute
      included group names, such as 'all', the unsupported attributes
      MUST NOT include attributes described in this document but not
      supported by the implementation.

   Group 3: Printer Attributes

      This is the set of requested attributes and their current values.
      The Printer ignores (does not respond with) any requested
      attribute that is not supported.  The Printer MAY respond with a
      subset of the supported attributes and values, depending on the
      security policy in force.  However, the Printer MUST respond with
      the 'unknown' value for any supported attribute (including all
      REQUIRED attributes) for which the Printer does not know the
      value.  Also, the Printer MUST respond with 'no-value' for any
      supported attribute (including all REQUIRED attributes) for which
      the Administrator has not configured a value.  See the description
      of the "out-of-band" values in the beginning of Section 5.1.

4.2.6.  Get-Jobs Operation

   This REQUIRED operation allows a Client to retrieve the list of Jobs
   belonging to the target Printer.  The Client can also supply a list
   of Job attribute names and/or attribute group names.  A group of Job
   attributes will be returned for each Job that is returned.

   This operation is similar to the Get-Job-Attributes operation, except
   that this Get-Jobs operation returns attributes from possibly more
   than one Job.














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4.2.6.1.  Get-Jobs Request

   The Client submits the Get-Jobs request to a Printer.

   The following groups of attributes are part of the Get-Jobs request:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.

      Target:

         The "printer-uri" (uri) operation attribute, which is the
         target for this operation as described in Section 4.1.5.

      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.

      "limit" (integer(1:MAX)):

         The Client MAY supply and the Printer MUST support this
         attribute.  It is an integer value that determines the maximum
         number of Jobs that a Client will receive from the Printer even
         if "which-jobs" or "my-jobs" (described below) constrain which
         Jobs are returned.  The limit is a "stateless limit" in that if
         the value supplied by the Client is 'N', then only the first
         'N' Jobs are returned in the Get-Jobs response.  If the Client
         does not supply this attribute, the Printer responds with all
         applicable Jobs.

      "requested-attributes" (1setOf type2 keyword):

         The Client MAY supply and the Printer MUST support this
         attribute.  It is a set of Job attribute names and/or attribute
         group names in whose values the requester is interested.  This
         set of attributes is returned for each Job that is returned.
         The allowed attribute group names are the same as those defined
         in the Get-Job-Attributes operation in Section 4.3.4.  If the
         Client does not supply this attribute, the Printer MUST respond
         as if the Client had supplied this attribute with two values:
         "job-uri" and "job-id".





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      "which-jobs" (type2 keyword):

         The Client MAY supply and the Printer MUST support this
         attribute.  It indicates which Jobs MUST be returned by the
         Printer.  The values for this attribute include:

         +  'completed': Any Job whose state is 'completed', 'canceled',
            or 'aborted'.

         +  'not-completed': Any Job whose state is 'pending',
            'processing', 'processing-stopped', or 'pending-held'.

         A Printer MUST support both values.  However, if the
         implementation does not keep Jobs in the 'completed',
         'canceled', and 'aborted' states, then it returns no Jobs when
         the 'completed' value is supplied.

         If a Client supplies some other value that is not supported by
         the Printer, the Printer MUST copy the attribute and the
         unsupported value to the Unsupported Attributes group, reject
         the request, and return the
         'client-error-attributes-or-values-not-supported' status-code.

         If the Client does not supply this attribute, the Printer MUST
         respond as if the Client had supplied the attribute with a
         value of 'not-completed'.

      "my-jobs" (boolean):

         The Client MAY supply and the Printer MUST support this
         attribute.  It indicates whether Jobs from all users or just
         the Jobs submitted by the requesting user of this request MUST
         be considered as candidate Jobs to be returned by the Printer.
         If the Client does not supply this attribute, the Printer MUST
         respond as if the Client had supplied the attribute with a
         value of 'false', i.e., Jobs from all users.  The means for
         authenticating the requesting user and matching the Jobs is
         described in Section 9.

4.2.6.2.  Get-Jobs Response

   The Printer returns all of the Jobs up to the number specified by the
   "limit" attribute that match the criteria as defined by the attribute
   values supplied by the Client in the request.  It is possible that no
   Jobs are returned, since there can literally be no Jobs at the
   Printer or there can be no Jobs that match the criteria supplied by
   the Client.  If the Client requests any Job attributes at all, there
   is a set of Job Attributes returned for each Job.



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   It is not an error for the Printer to return 0 Jobs.  If the response
   returns 0 Jobs because there are no Jobs matching the criteria, and
   the request would have returned one or more Jobs with a status-code
   of 'successful-ok' if there had been Jobs matching the criteria, then
   the status-code for 0 Jobs MUST be 'successful-ok'.

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.

   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.

      The response MAY contain the "requested-attributes" operation
      attribute with any supplied values (attribute keywords) that were
      requested by the Client but are not supported by the Printer.  If
      the Printer does return unsupported attributes referenced in the
      "requested-attributes" operation attribute and that attribute
      included group names, such as 'all', the unsupported attributes
      MUST NOT include attributes described in this document but not
      supported by the implementation.

   Groups 3 to N: Job Attributes

      The Printer responds with one set of Job Attributes for each
      returned Job.  The Printer ignores (does not respond with) any
      requested attribute or value that is not supported or that is
      restricted by the security policy in force, including whether the
      requesting user is the user that submitted the Job
      (Job-originating user) or not (see Section 9).  However, the
      Printer MUST respond with the 'unknown' value for any supported
      attribute (including all REQUIRED attributes) for which the
      Printer does not know the value, unless it would violate the
      security policy.  See the description of the "out-of-band" values
      in the beginning of Section 5.1.




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      Jobs are returned in the following order:

      *  If the Client requests all 'completed' Jobs (Jobs in the
         'completed', 'aborted', or 'canceled' states), then the Jobs
         are returned newest to oldest (with respect to actual
         completion time).

      *  If the Client requests all 'not-completed' Jobs (Jobs in the
         'pending', 'processing', 'pending-held', and
         'processing-stopped' states), then Jobs are returned in
         relative chronological order of expected time to complete
         (based on whatever scheduling algorithm is configured for the
         Printer).

4.2.7.  Pause-Printer Operation

   This OPTIONAL operation allows a Client to stop the Printer from
   scheduling Jobs on all its devices.  Depending on implementation, the
   Pause-Printer operation MAY also stop the Printer from processing the
   current Job or Jobs.  Any Job that is currently being printed is
   either (1) stopped as soon as the implementation permits or
   (2) completed, depending on implementation.  The Printer MUST still
   accept Job Creation requests to create new Jobs but MUST prevent any
   Jobs from entering the 'processing' state.

   If the Pause-Printer operation is supported, then the Resume-Printer
   operation MUST be supported, and vice versa.

   The IPP Printer stops the current Job(s) on its device or devices
   that were in the 'processing' or 'processing-stopped' state as soon
   as the implementation permits.  If the implementation will take
   appreciable time to stop, the IPP Printer adds the 'moving-to-paused'
   value to the Printer's "printer-state-reasons" attribute (see
   Section 5.4.12).  When the device or devices have all stopped, the
   IPP Printer transitions the Printer to the 'stopped' state; removes
   the 'moving-to-paused' value, if present; and adds the 'paused' value
   to the Printer's "printer-state-reasons" attribute.

   When the current Job or Jobs complete that were in the 'processing'
   state, the IPP Printer transitions them to the 'completed' state.
   When the current Job or Jobs stop in mid-processing that were in the
   'processing' state, the IPP Printer transitions them to the
   'processing-stopped' state and adds the 'printer-stopped' value to
   the Jobs' "job-state-reasons" attribute.







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   For any Jobs that are 'pending' or 'pending-held', the
   'printer-stopped' value of the Jobs' "job-state-reasons" attribute
   also applies.  However, the IPP Printer MAY update those Jobs'
   "job-state-reasons" values when those Jobs are queried (so-called
   "lazy evaluation").

   The IPP Printer MUST accept the request in any state and transition
   the Printer to the indicated new "printer-state" before returning, as
   shown in Table 2.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation MUST be an Operator or Administrator of the Printer
   (see Sections 1 and 9.5).  Otherwise, the IPP Printer MUST reject the
   operation and return 'client-error-forbidden',
   'client-error-not-authenticated', or 'client-error-not-authorized'
   as appropriate.



































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   +--------------+--------------+-----------------+-------------------+
   | Current      | New          | "printer-state- | IPP Printer's     |
   | "printer-    | "printer-    | reasons"        | response status-  |
   | state"       | state"       |                 | code and action:  |
   +--------------+--------------+-----------------+-------------------+
   | 'idle'       | 'stopped'    | 'paused'        | 'successful-ok'   |
   +--------------+--------------+-----------------+-------------------+
   | 'processing' | 'processing' | 'moving-to-     | Option 1:         |
   |              |              | paused'         | 'successful-ok';  |
   |              |              |                 | Later, when all   |
   |              |              |                 | output has        |
   |              |              |                 | stopped, the      |
   |              |              |                 | "printer-state"   |
   |              |              |                 | becomes           |
   |              |              |                 | 'stopped', and    |
   |              |              |                 | the 'paused'      |
   |              |              |                 | value replaces    |
   |              |              |                 | the 'moving-to-   |
   |              |              |                 | paused' value in  |
   |              |              |                 | the "printer-     |
   |              |              |                 | state-reasons"    |
   |              |              |                 | attribute         |
   +--------------+--------------+-----------------+-------------------+
   | 'processing' | 'stopped'    | 'paused'        | Option 2:         |
   |              |              |                 | 'successful-ok';  |
   |              |              |                 | all device output |
   |              |              |                 | stopped           |
   |              |              |                 | immediately       |
   +--------------+--------------+-----------------+-------------------+
   | 'stopped'    | 'stopped'    | 'paused'        | 'successful-ok'   |
   +--------------+--------------+-----------------+-------------------+

                 Table 2: Pause-Printer State Transitions


















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4.2.7.1.  Pause-Printer Request

   The following groups of attributes are part of the Pause-Printer
   request:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.

      Target:

         The "printer-uri" (uri) operation attribute, which is the
         target for this operation as described in Section 4.1.5.

      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.

4.2.7.2.  Pause-Printer Response

   The following groups of attributes are part of the Pause-Printer
   response:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.

   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.






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4.2.8.  Resume-Printer Operation

   This OPTIONAL operation allows a Client to resume the Printer
   scheduling Jobs on all its devices.  The Printer MUST remove the
   'paused' and 'moving-to-paused' values from the Printer's
   "printer-state-reasons" attribute, if present.  If there are no other
   reasons to keep a device paused (such as a media jam), the IPP
   Printer is free to transition itself to the 'processing' or 'idle'
   state, depending on whether there are Jobs to be processed or not,
   respectively, and the device(s) resumes processing Jobs.

   If the Pause-Printer operation is supported, then the Resume-Printer
   operation MUST be supported, and vice versa.

   The IPP Printer removes the 'printer-stopped' value from any Job's
   "job-state-reasons" attributes contained in that Printer.

   The IPP Printer MUST accept the request in any state and transition
   the Printer to the indicated new state as shown in Table 3.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation MUST be an Operator or Administrator of the Printer
   (see Sections 1 and 9.5).  Otherwise, the IPP Printer MUST reject the
   operation and return 'client-error-forbidden',
   'client-error-not-authenticated', or 'client-error-not-authorized'
   as appropriate.

   The Resume-Printer request and Resume-Printer response have the same
   attribute groups and attributes as the Pause-Printer operation (see
   Sections 4.2.7.1 and 4.2.7.2).

   +-----------------+-----------------+-------------------------------+
   | Current         | New "printer-   | IPP Printer's response        |
   | "printer-state" | state"          | status-code and action:       |
   +-----------------+-----------------+-------------------------------+
   | 'idle'          | 'idle'          | 'successful-ok'               |
   +-----------------+-----------------+-------------------------------+
   | 'processing'    | 'processing'    | 'successful-ok'               |
   +-----------------+-----------------+-------------------------------+
   | 'stopped'       | 'processing'    | 'successful-ok', when there   |
   |                 |                 | are Jobs to be processed      |
   +-----------------+-----------------+-------------------------------+
   | 'stopped'       | 'idle'          | 'successful-ok', when there   |
   |                 |                 | are no Jobs to be processed   |
   +-----------------+-----------------+-------------------------------+

                 Table 3: Resume-Printer State Transitions




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4.2.9.  Purge-Jobs Operation

   This DEPRECATED operation allows a Client to remove all Jobs from a
   Printer, regardless of their Job states, including Jobs in the
   Printer's Job History (see Section 5.3.7.2).  After a Purge-Jobs
   operation has been performed, a Printer MUST return no Jobs in
   subsequent Get-Job-Attributes and Get-Jobs responses (until new Jobs
   are submitted).

   Note: This operation SHOULD NOT be supported in new implementations,
   since it destroys Printer accounting information.

   Whether the Purge-Jobs (and Get-Jobs) operation affects Jobs that
   were submitted to the device from sources other than the IPP Printer
   in the same way that the Purge-Jobs operation affects Jobs that were
   submitted to the IPP Printer using IPP depends on implementation,
   i.e., on whether IPP is being used as a universal management protocol
   or just to manage IPP Jobs, respectively.

   Note: If an Operator wants to cancel all Jobs without clearing out
   the Job History, the Operator uses the Cancel-Job operation on each
   Job instead of using the Purge-Jobs operation.

   If this OPTIONAL operation is supported, the Printer MUST accept this
   operation in any state and transition the Printer to the 'idle'
   state.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation MUST be an Operator or Administrator of the Printer
   (see Sections 1 and 9.5).  Otherwise, the Printer MUST reject the
   operation and return 'client-error-forbidden',
   'client-error-not-authenticated', and 'client-error-not-authorized'
   as appropriate.

   The Purge-Jobs request and Purge-Jobs response have the same
   attribute groups and attributes as the Pause-Printer operation (see
   Sections 4.2.7.1 and 4.2.7.2).

4.3.  Job Operations

   All Job operations are directed at Jobs.  A Client MUST always supply
   some means of identifying the Job object in order to identify the
   correct target of the operation.  That Job identification SHOULD be
   the combination of a Printer URI with a Job ID but MAY be the
   (single) Job URI.  The IPP implementation MUST support both forms of
   identification for every Job.





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4.3.1.  Send-Document Operation

   This RECOMMENDED operation allows a Client to add a Document to a Job
   that was created using the Create-Job operation.  In the Create-Job
   response, the Printer returns the Job's URI (the "job-uri" attribute)
   and the Job's 32-bit identifier (the "job-id" attribute).  For each
   new Document that the Client desires to add, the Client uses a
   Send-Document operation.  Each Send-Document request contains the
   entire stream of Document data for one Document.

   If the Printer supports this operation but does not support multiple
   Documents per Job, the Printer MUST reject subsequent Send-Document
   operations supplied with data and return the
   'server-error-multiple-document-jobs-not-supported' status-code.
   However, the Printer MUST accept the first Document with a 'true' or
   'false' value for the "last-document" operation attribute (see
   below), so that Clients MAY always submit one Document Job with a
   'false' value for "last-document" in the first Send-Document and a
   'true' value for "last-document" in the second Send-Document (with
   no data).

   Since the Create-Job and the send operations (Send-Document or
   Send-URI operations) that follow could occur over an arbitrarily long
   period of time for a particular Job, a Client MUST send another send
   operation within a minimum time interval, as defined by the IPP
   Printer, after the receipt of the previous request for the Job.  If a
   Printer supports the Create-Job and Send-Document operations, the
   Printer MUST support the "multiple-operation-time-out" attribute (see
   Section 5.4.31).  This attribute indicates the minimum number of
   seconds the Printer will wait for the next send operation before
   taking some recovery action.

   A Printer MUST recover from an errant Client that does not supply a
   send operation, sometime after the minimum time interval specified by
   the Printer's "multiple-operation-time-out" attribute.  Such recovery
   MAY include any of the following actions or other recovery actions:

   1.  Assume that the Job is an invalid Job, start the process of
       changing the Job state to 'aborted', add the 'aborted-by-system'
       value to the Job's "job-state-reasons" attribute (see
       Section 5.3.8), and clean up all resources associated with the
       Job.  In this case, if another send operation is finally
       received, the Printer responds with a 'client-error-not-possible'
       or 'client-error-not-found' status-code, depending on whether the
       Job is still around when the send operation finally arrives.






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   2.  Assume that the last send operation received was in fact the last
       Document (as if the "last-document" flag had been set to 'true'),
       close the Job, and proceed to process it (i.e., move the Job's
       state to 'pending').

   3.  Assume that the last send operation received was in fact the last
       Document and close the Job, but move it to the 'pending-held'
       state and add the 'submission-interrupted' value to the Job's
       "job-state-reasons" attribute (see Section 5.3.8).  This action
       allows the user or an Operator to determine whether to continue
       processing the Job by moving it back to the 'pending' state using
       the Release-Job operation (see Section 4.3.6) or to cancel the
       Job using the Cancel-Job operation (see Section 4.3.3).

   Each implementation is free to decide the "best" action to take,
   depending on the following: local policy, whether any Documents have
   been added, whether the implementation spools Jobs or not, and/or any
   other piece of information available to it.  If the choice is to
   abort the Job, it is possible that the Job has already been processed
   to the point that some Media Sheet pages have been printed.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation must be either the Job owner (as determined in the
   Create-Job operation) or an Operator or Administrator of the Printer
   (see Sections 1 and 9.5).  Otherwise, the Printer MUST reject the
   operation and return 'client-error-forbidden',
   'client-error-not-authenticated', or 'client-error-not-authorized'
   as appropriate.

4.3.1.1.  Send-Document Request

   The following attribute sets are part of the Send-Document request:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.

      Target:

         Either the "printer-uri" (uri) plus "job-id" (integer(1:MAX)),
         or the "job-uri" (uri) operation attribute(s), which define the
         target for this operation as described in Section 4.1.5.






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      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.

      "document-name" (name(MAX)):

         The Client MAY supply and the Printer MUST support this
         attribute.  It contains the Client-supplied Document name.  The
         Document name MAY be different than the Job name and is not
         guaranteed to be unique across multiple Documents in the same
         Job.  Typically, the Client software automatically supplies the
         Document name on behalf of the End User by using a file name or
         an application-generated name.  See the description of the
         "document-name" operation attribute in the Print-Job request
         (Section 4.2.1.1) for more information about this attribute.

      "compression" (type2 keyword):

         See the description of "compression" for the Print-Job
         operation in Section 4.2.1.1.

      "document-format" (mimeMediaType):

         See the description of "document-format" for the Print-Job
         operation in Section 4.2.1.1.

      "document-natural-language" (naturalLanguage):

         The Client MAY supply and the Printer MAY support this
         attribute.  It specifies the natural language of the Document
         content for those Document formats that require a specification
         of the natural language in order to properly image the
         Document.

      "last-document" (boolean):

         The Client MUST supply and the Printer MUST support this
         attribute.  It is a boolean flag that is set to 'true' if this
         is the last Document for the Job; otherwise, it is set to
         'false'.










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   Group 2: Document Data

      The Client MUST supply the Document data if the "last-document"
      flag is set to 'false'.  However, since a Client might not know
      that the previous Document sent with a Send-Document (or Send-URI)
      operation was the last Document (i.e., the "last-document"
      attribute was set to 'false'), it is legal to send a Send-Document
      request with no Document data where the "last-document" flag is
      set to 'true'.  Such a request MUST NOT increment the value of the
      Job's "number-of-documents" attribute, since no real Document was
      added to the Job.  It is not an error for a Client to submit a Job
      with no actual Document data, i.e., only a single Create-Job and
      Send-Document request with a "last-document" operation attribute
      set to 'true' with no Document data.

4.3.1.2.  Send-Document Response

   The following sets of attributes are part of the Send-Document
   response:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.

   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.

   Group 3: Job Object Attributes

      This is the same set of attributes as those described in the
      Print-Job response (see Section 4.2.1.2).








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4.3.2.  Send-URI Operation

   This RECOMMENDED operation is identical to the Send-Document
   operation (see Section 4.3.1), except that a Client MUST supply a URI
   reference ("document-uri" operation attribute) rather than the
   Document data itself.  If a Printer supports this operation, Clients
   can use both Send-URI and Send-Document operations to add new
   Documents to an existing Job.  However, if a Client needs to indicate
   that the previous Send-URI or Send-Document was the last Document,
   the Client MUST use the Send-Document operation with no Document data
   and the "last-document" flag set to 'true' (rather than using a
   Send-URI operation with no "document-uri" operation attribute).

   If a Printer supports this operation, it MUST also support the
   Print-URI operation (see Section 4.2.2).

   The Printer MUST validate the syntax and URI scheme of the supplied
   URI before returning a response, just as in the Print-URI operation.
   The Printer MAY validate the accessibility of the Document as part of
   the operation, or subsequently (see Section 4.2.2).

4.3.3.  Cancel-Job Operation

   This REQUIRED operation allows a Client to cancel a Print Job from
   the time the Job is created up to the time it is completed, canceled,
   or aborted.  Since a Job might already be printing by the time a
   Cancel-Job is received, some Media Sheet pages might be printed
   before the Job is actually terminated.

   The Printer MUST accept or reject the request based on the Job's
   current state and transition the Job to the indicated new state as
   shown in Table 4.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation must be either the Job owner or an Operator or
   Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
   the Printer MUST reject the operation and return
   'client-error-forbidden', 'client-error-not-authenticated', or
   'client-error-not-authorized' as appropriate.












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   +-------------------+--------------------+--------------------------+
   | Current "job-     | New "job-state"    | Printer's response       |
   | state"            |                    | status-code and action:  |
   +-------------------+--------------------+--------------------------+
   | 'pending'         | 'canceled'         | 'successful-ok'          |
   +-------------------+--------------------+--------------------------+
   | 'pending-held'    | 'canceled'         | 'successful-ok'          |
   +-------------------+--------------------+--------------------------+
   | 'processing'      | 'canceled'         | 'successful-ok'          |
   +-------------------+--------------------+--------------------------+
   | 'processing'      | 'processing'       | 'successful-ok' (note 1) |
   +-------------------+--------------------+--------------------------+
   | 'processing'      | 'processing'       | 'client-error-not-       |
   |                   |                    | possible' (note 2)       |
   +-------------------+--------------------+--------------------------+
   | 'processing-      | 'canceled'         | 'successful-ok'          |
   | stopped'          |                    |                          |
   +-------------------+--------------------+--------------------------+
   | 'processing-      | 'processing-       | 'successful-ok' (note 1) |
   | stopped'          | stopped'           |                          |
   +-------------------+--------------------+--------------------------+
   | 'processing-      | 'processing-       | 'client-error-not-       |
   | stopped'          | stopped'           | possible' (note 2)       |
   +-------------------+--------------------+--------------------------+
   | 'completed'       | 'completed'        | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'canceled'        | 'canceled'         | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'aborted'         | 'aborted'          | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+

                   Table 4: Cancel-Job State Transitions

   Note 1: If the implementation requires some measurable time to cancel
   the Job in the 'processing' or 'processing-stopped' Job state, the
   Printer MUST add the 'processing-to-stop-point' value to the Job's
   "job-state-reasons" attribute and then transition the Job to the
   'canceled' state when the processing ceases (see Section 5.3.8).

   Note 2: If the Job already has the 'processing-to-stop-point' value
   in its "job-state-reasons" attribute, then the Printer MUST reject a
   Cancel-Job operation.






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4.3.3.1.  Cancel-Job Request

   The following groups of attributes are part of the Cancel-Job
   request:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.

      Target:

         Either the "printer-uri" (uri) plus "job-id" (integer(1:MAX)),
         or the "job-uri" (uri) operation attribute(s), which define the
         target for this operation as described in Section 4.1.5.

      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.

      "message" (text(127)):

         The Client MAY supply and the Printer MAY support this
         attribute.  It is a message to the Operator.  This "message"
         attribute is not the same as the "job-message-from-operator"
         attribute.  That attribute is used to report a message from the
         Operator to the End User that queries that attribute.  This
         "message" operation attribute is used to send a message from
         the Client to the Operator along with the operation request.
         How or where to display this message to the Operator (if
         at all) is an implementation decision.

















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4.3.3.2.  Cancel-Job Response

   The following sets of attributes are part of the Cancel-Job response:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.

   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.

      Once a successful response has been sent, the implementation
      guarantees that the Job will eventually end up in the 'canceled'
      state.  Between the time that the Cancel-Job operation is accepted
      and when the Job enters the 'canceled' job-state (see
      Section 5.3.7), the "job-state-reasons" attribute SHOULD contain
      the 'processing-to-stop-point' value, which indicates to later
      queries that although the Job might still be 'processing' it will
      eventually end up in the 'canceled' state, not the 'completed'
      state.

4.3.4.  Get-Job-Attributes Operation

   This REQUIRED operation allows a Client to request the values of
   attributes of a Job, and it is almost identical to the
   Get-Printer-Attributes operation (see Section 4.2.5).  The only
   differences are that the operation is directed at a Job rather than a
   Printer, there is no "document-format" operation attribute used when
   querying a Job, and the returned attribute group is a set of Job
   attributes rather than a set of Printer attributes.









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   For Jobs, the possible names of attribute groups are:

   o  'job-template': the subset of the Job Template attributes that
      apply to a Job (the first column of Table 8 in Section 5.2) that
      the implementation supports for Jobs.

   o  'job-description': the subset of the Job Description and Status
      attributes specified in Section 5.3 that the implementation
      supports for Jobs.

   o  'all': the special group 'all' that includes all attributes that
      the implementation supports for Jobs.

   Since a Client MAY request specific attributes or named groups, there
   is a potential for some overlap.  For example, if a Client requests
   'job-name' and 'job-description', the Client is actually requesting
   the "job-name" attribute once by naming it explicitly, and once by
   inclusion in the 'job-description' group.  In such cases, the Printer
   returns the attribute only once in the response even if it is
   requested multiple times.  The Client SHOULD NOT request the same
   attribute in multiple ways.

   Jobs MUST support all group names and MUST return all supported
   attributes belonging to the group.

4.3.4.1.  Get-Job-Attributes Request

   The following groups of attributes are part of the Get-Job-Attributes
   request when the request is directed at a Job:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.1.

      Target:

         Either the "printer-uri" (uri) plus "job-id" (integer(1:MAX)),
         or the "job-uri" (uri) operation attribute(s), which define the
         target for this operation as described in Section 4.1.5.

      Requesting User Name:

         The "requesting-user-name" (name(MAX)) attribute SHOULD be
         supplied by the Client as described in Section 9.3.




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      "requested-attributes" (1setOf keyword):

         The Client MAY supply and the Printer MUST support this
         attribute.  It is a set of attribute names and/or attribute
         group names in whose values the requester is interested.  If
         the Client omits this attribute, the Printer MUST respond as if
         this attribute had been supplied with a value of 'all'.

4.3.4.2.  Get-Job-Attributes Response

   The Printer returns the following sets of attributes as part of the
   Get-Job-Attributes response:

   Group 1: Operation Attributes

      Natural Language and Character Set:

         The "attributes-charset" and "attributes-natural-language"
         attributes as described in Section 4.1.4.2.
         "attributes-natural-language" MAY be the natural language of
         the Job, rather than the one requested.

      Status Message:

         In addition to the REQUIRED status-code returned in every
         response, the response MAY include a "status-message"
         (text(255)) and/or a "detailed-status-message" (text(MAX))
         operation attribute as described in Appendix B and
         Section 4.1.6.

   Group 2: Unsupported Attributes

      See Section 4.1.7 for details on returning unsupported attributes.

      The response MAY contain the "requested-attributes" operation
      attribute with any supplied values (attribute keywords) that were
      requested by the Client but are not supported by the Printer.  If
      the Printer does return unsupported attributes referenced in the
      "requested-attributes" operation attribute and that attribute
      included group names, such as 'all', the unsupported attributes
      MUST NOT include attributes described in this document but not
      supported by the implementation.









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   Group 3: Job Attributes

      This is the set of requested attributes and their current values.
      The Printer ignores (does not respond with) any requested
      attribute or value that is not supported or that is restricted by
      the security policy in force, including whether the requesting
      user is the user that submitted the Job (Job-originating user) or
      not (see Section 9).  However, the Printer MUST respond with the
      'unknown' value for any supported attribute (including all
      REQUIRED attributes) for which the Printer does not know the
      value, unless it would violate the security policy.  See the
      description of the "out-of-band" values in the beginning of
      Section 5.1.

4.3.5.  Hold-Job Operation

   This OPTIONAL operation allows a Client to hold a pending Job in the
   queue so that it is not eligible for scheduling.  If the Hold-Job
   operation is supported, then the Release-Job operation MUST be
   supported, and vice versa.  The OPTIONAL "job-hold-until" operation
   attribute allows a Client to specify whether to hold the Job
   indefinitely or until a specified time period, if supported.

   The Printer MUST accept or reject the request based on the Job's
   current state and transition the Job to the indicated new state as
   shown in Table 5.

   Note: In order to keep the Hold-Job operation simple, such a request
   is rejected when the Job is in the 'processing' or
   'processing-stopped' state.  If an operation is needed to hold Jobs
   while in either of these states, it will be added as an additional
   operation, rather than overloading the Hold-Job operation.  Then it
   is clear to Clients by querying the Printer's "operations-supported"
   (see Section 5.4.15) and the Job's "job-state" (see Section 5.3.7)
   attributes which operations are possible.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation must be either the Job owner or an Operator or
   Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
   the Printer MUST reject the operation and return
   'client-error-forbidden', 'client-error-not-authenticated', or
   'client-error-not-authorized' as appropriate.









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   +-------------------+--------------------+--------------------------+
   | Current "job-     | New "job-state"    | Printer's response       |
   | state"            |                    | status-code and action:  |
   +-------------------+--------------------+--------------------------+
   | 'pending'         | 'pending-held'     | 'successful-ok' (note 1) |
   +-------------------+--------------------+--------------------------+
   | 'pending'         | 'pending'          | 'successful-ok' (note 2) |
   +-------------------+--------------------+--------------------------+
   | 'pending-held'    | 'pending-held'     | 'successful-ok' (note 1) |
   +-------------------+--------------------+--------------------------+
   | 'pending-held'    | 'pending'          | 'successful-ok' (note 2) |
   +-------------------+--------------------+--------------------------+
   | 'processing'      | 'processing'       | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'processing-      | 'processing-       | 'client-error-not-       |
   | stopped'          | stopped'           | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'completed'       | 'completed'        | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'canceled'        | 'canceled'         | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'aborted'         | 'aborted'          | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+

                    Table 5: Hold-Job State Transitions

   Note 1: If the implementation supports multiple reasons for a Job to
   be in the 'pending-held' state, the Printer MUST add the
   "job-hold-until-specified" value to the Job's "job-state-reasons"
   attribute.

   Note 2: If the Printer supports the "job-hold-until" operation
   attribute, but the specified time period has already started (or is
   the 'no-hold' value) and there are no other reasons to hold the Job,
   the Printer MUST make the Job be a candidate for processing
   immediately (see Section 5.2.2) by putting the Job in the 'pending'
   state.










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4.3.5.1.  Hold-Job Request

   The groups and operation attributes are the same as those defined for
   a Cancel-Job request (see Section 4.3.3.1), with the addition of the
   following Group 1 operation attribute:

      "job-hold-until" (type2 keyword | name(MAX)):

      The Client MAY supply and the Printer MUST support this operation
      attribute in a Hold-Job request if it supports the
      "job-hold-until" Job Template attribute in Job Creation requests.
      See Section 5.2.2.  The Printer SHOULD support the
      "job-hold-until" Job Template attribute for use in Job Creation
      requests with at least the 'indefinite' value, if it supports the
      Hold-Job operation.  Otherwise, a Client cannot create a Job and
      hold it immediately (without picking some supported time period in
      the future).

      If supplied and supported as specified in the Printer's
      "job-hold-until-supported" attribute, the Printer copies the
      supplied operation attribute to the Job, replacing the Job's
      previous "job-hold-until" attribute, if present, and makes the Job
      a candidate for scheduling during the supplied named time period.

      If supplied but either the "job-hold-until" operation attribute
      itself or the value supplied is not supported, the Printer accepts
      the request, returns the unsupported attribute or value in the
      Unsupported Attributes group according to Section 4.1.7, returns
      the 'successful-ok-ignored-or-substituted-attributes' status-code,
      and holds the Job indefinitely until a Client performs a
      subsequent Release-Job operation.

      If (1) the Client supplies either a value that specifies a time
      period that has already started or the 'no-hold' value (meaning
      don't hold the Job) and (2) the Printer supports the
      "job-hold-until" operation attribute and there are no other
      reasons to hold the Job, the Printer MUST accept the operation and
      make the Job be a candidate for processing immediately (see
      Section 5.2.2).

      If the Client does not supply a "job-hold-until" operation
      attribute in the request, the Printer MUST populate the Job with a
      "job-hold-until" attribute with the 'indefinite' value (if the
      Printer supports the "job-hold-until" attribute) and hold the Job
      indefinitely, until a Client performs a Release-Job operation.






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4.3.5.2.  Hold-Job Response

   The groups and attributes are the same as those defined for a
   Cancel-Job response (see Section 4.3.3.2).

4.3.6.  Release-Job Operation

   This OPTIONAL operation allows a Client to release a previously held
   Job so that it is again eligible for scheduling.  If the Hold-Job
   operation is supported, then the Release-Job operation MUST be
   supported, and vice versa.

   This operation removes the "job-hold-until" Job attribute, if
   present, from the Job that had been supplied in the Create-Job or
   most recent Hold-Job or Restart-Job operation and removes its effect
   on the Job.  The Printer MUST remove the "job-hold-until-specified"
   value from the Job's "job-state-reasons" attribute, if present.  See
   Section 5.3.8.

   The Printer MUST accept or reject the request based on the Job's
   current state and transition the Job to the indicated new state as
   shown in Table 6.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation must be either the Job owner or an Operator or
   Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
   the Printer MUST reject the operation and return
   'client-error-forbidden', 'client-error-not-authenticated', or
   'client-error-not-authorized' as appropriate.

   The Release-Job request and Release-Job response have the same
   attribute groups and attributes as the Cancel-Job operation (see
   Sections 4.3.3.1 and 4.3.3.2).


















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   +-------------------+--------------------+--------------------------+
   | Current "job-     | New "job-state"    | Printer's response       |
   | state"            |                    | status-code and action:  |
   +-------------------+--------------------+--------------------------+
   | 'pending'         | 'pending'          | 'successful-ok'.  No     |
   |                   |                    | effect on the Job.       |
   +-------------------+--------------------+--------------------------+
   | 'pending-held'    | 'pending-held'     | 'successful-ok' (note 1) |
   +-------------------+--------------------+--------------------------+
   | 'pending-held'    | 'pending'          | 'successful-ok'          |
   +-------------------+--------------------+--------------------------+
   | 'processing'      | 'processing'       | 'successful-ok'.  No     |
   |                   |                    | effect on the Job.       |
   +-------------------+--------------------+--------------------------+
   | 'processing-      | 'processing-       | 'successful-ok'.  No     |
   | stopped'          | stopped'           | effect on the Job.       |
   +-------------------+--------------------+--------------------------+
   | 'completed'       | 'completed'        | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'canceled'        | 'canceled'         | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'aborted'         | 'aborted'          | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+

                  Table 6: Release-Job State Transitions

   Note 1: If there are other reasons to keep the Job in the
   'pending-held' state, such as 'resources-are-not-ready', the Job
   remains in the 'pending-held' state.  Thus, the 'pending-held' state
   is not just for Jobs that have the "job-hold-until" attribute applied
   to them but is also used for any reason that will keep the Job from
   being a candidate for scheduling and processing, such as
   'resources-are-not-ready'.  See the "job-hold-until" attribute
   (Section 5.2.2).














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4.3.7.  Restart-Job Operation

   This DEPRECATED operation allows a Client to restart a Job that is
   retained in the queue after processing has completed (see
   Section 5.3.7.2).

   Note: This operation SHOULD NOT be supported in new implementations,
   since it destroys Printer accounting information.  The Resubmit-Job
   operation [PWG5100.11] is the safe replacement for this operation and
   makes a copy of the Job, assigns a new "job-uri" and "job-id" to the
   copy, and resets the Job progress attributes in the new copy only.

   The Restart-Job operation moves the Job to the 'pending' or
   'pending-held' Job state and restarts at the beginning on the same
   Printer with the same attribute values.  If any of the Documents in
   the Job were passed by reference (Print-URI or Send-URI), the Printer
   MUST refetch the data, since the semantics of Restart-Job are to
   repeat all Job processing.  The Job Status attributes that accumulate
   Job progress, such as "job-impressions-completed",
   "job-media-sheets-completed", and "job-k-octets-processed", MUST be
   reset to 0 so that they give an accurate record of the Job from its
   restart point.  The Job MUST continue to use the same "job-uri" and
   "job-id" attribute values.

   The Printer MUST accept or reject the request based on the Job's
   current state and transition the Job to the indicated new state as
   shown in Table 7.

   Note: In order to prevent a user from inadvertently restarting a Job
   in the middle, the Restart-Job request is rejected when the Job is in
   the 'processing' or 'processing-stopped' state.  If in the future an
   operation is needed to hold or restart Jobs while in either of these
   states, it will be added as an additional operation, rather than
   overloading the Restart-Job operation, so that it is clear that the
   user intended that the current Job not be completed.

   Access Rights: The authenticated user (see Section 9.3) performing
   this operation must be either the Job owner or an Operator or
   Administrator of the Printer (see Sections 1 and 9.5).  Otherwise,
   the Printer MUST reject the operation and return
   'client-error-forbidden', 'client-error-not-authenticated', or
   'client-error-not-authorized' as appropriate.









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   +-------------------+--------------------+--------------------------+
   | Current "job-     | New "job-state"    | Printer's response       |
   | state"            |                    | status-code and action:  |
   +-------------------+--------------------+--------------------------+
   | 'pending'         | 'pending'          | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'pending-held'    | 'pending-held'     | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'processing'      | 'processing'       | 'client-error-not-       |
   |                   |                    | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'processing-      | 'processing-       | 'client-error-not-       |
   | stopped'          | stopped'           | possible'                |
   +-------------------+--------------------+--------------------------+
   | 'completed'       | 'pending' or       | 'successful-ok' - Job is |
   |                   | 'pending-held'     | started over.            |
   +-------------------+--------------------+--------------------------+
   | 'completed'       | 'completed'        | 'client-error-not-       |
   |                   |                    | possible' - see Rule 1.  |
   +-------------------+--------------------+--------------------------+
   | 'canceled'        | 'pending' or       | 'successful-ok' - Job is |
   |                   | 'pending-held'     | started over.            |
   +-------------------+--------------------+--------------------------+
   | 'canceled'        | 'canceled'         | 'client-error-not-       |
   |                   |                    | possible' - see Rule 1.  |
   +-------------------+--------------------+--------------------------+
   | 'aborted'         | 'pending' or       | 'successful-ok' - Job is |
   |                   | 'pending-held'     | started over.            |
   +-------------------+--------------------+--------------------------+
   | 'aborted'         | 'aborted'          | 'client-error-not-       |
   |                   |                    | possible' - see Rule 1.  |
   +-------------------+--------------------+--------------------------+

                  Table 7: Restart-Job State Transitions

   Rule 1: If the Job Retention Period has expired for the Job in this
   state, then the Printer rejects the operation.  See Section 5.3.7.2.












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4.3.7.1.  Restart-Job Request

   The groups and attributes are the same as those defined for a
   Cancel-Job request (see Section 4.3.3.1), with the addition of the
   following Group 1 operation attribute:

      "job-hold-until" (type2 keyword | name(MAX)):

      The Client MAY supply and the Printer MUST support this operation
      attribute in a Restart-Job request if it supports the
      "job-hold-until" Job Template attribute in Job Creation requests.
      See Section 5.2.2.

      If supplied and supported as specified in the Printer's
      "job-hold-until-supported" attribute, the Printer copies the
      supplied operation attribute to the Job, replacing the Job's
      previous "job-hold-until" attribute, if present, and makes the Job
      a candidate for scheduling during the supplied named time period.
      See Section 5.2.2.

      If supplied but the value is not supported, the Printer accepts
      the request, returns the unsupported attribute or value in the
      Unsupported Attributes group according to Section 4.1.7, returns
      the 'successful-ok-ignored-or-substituted-attributes' status-code,
      and holds the Job indefinitely until a Client performs a
      subsequent Release-Job operation.

      If supplied but the "job-hold-until" operation attribute itself is
      not supported, the Printer accepts the request, returns the
      unsupported attribute with the out-of-band 'unsupported' value in
      the Unsupported Attributes group according to Section 4.1.7,
      returns the 'successful-ok-ignored-or-substituted-attributes'
      status-code, and restarts the Job, i.e., ignores the
      "job-hold-until" attribute.

      If (1) the Client supplies either a value that specifies a time
      period that has already started or the 'no-hold' value (meaning
      don't hold the Job) and (2) the Printer supports the
      "job-hold-until" operation attribute and there are no other
      reasons to hold the Job, the Printer makes the Job a candidate for
      processing immediately (see Section 5.2.2).

      If the Client does not supply a "job-hold-until" operation
      attribute in the request, the Printer removes the "job-hold-until"
      attribute, if present, from the Job.  If there are no other
      reasons to hold the Job, the Restart-Job operation makes the Job a
      candidate for processing immediately (see Section 5.2.2).




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4.3.7.2.  Restart-Job Response

   The groups and attributes are the same as those defined for a
   Cancel-Job response (see Section 4.3.3.2).

5.  Object Attributes

   This section describes the attributes with their corresponding
   attribute syntaxes and values that are part of the IPP Model.  The
   sections below show the objects and their associated attributes that
   are included within the scope of this protocol.  Many of these
   attributes are derived from other relevant documents:

   o  Document Printing Application (DPA) [ISO10175]

   o  Printer MIB v2 [RFC3805]

   Each attribute is uniquely identified in this document using a
   "keyword" (see Section 2.3.7) that is the name of the attribute.  The
   keyword is included in the section title describing that attribute.

   Note: Not only are keywords used to identify attributes, but one of
   the attribute syntaxes described below is "keyword" so that some
   attributes have 'keyword' values.  Therefore, these attributes are
   defined as having an attribute syntax that is a set of keywords.

5.1.  Attribute Syntaxes

   This section defines the basic attribute syntax types that all
   Clients and IPP objects MUST be able to accept in responses and
   accept in requests, respectively.  Each attribute description in
   Sections 4 and 5 includes in the section title the name of the
   attribute with its syntax(es) in parentheses.  A conforming
   implementation of an attribute MUST include the semantics of the
   attribute syntax(es) so identified.  Section 7.7 describes how the
   protocol can be extended with new attribute syntaxes.

   The attribute syntaxes are specified in the following subsections,
   where the subsection title is the keyword name of the attribute
   syntax inside the single quotes.  In operation requests and
   responses, each attribute value MUST be represented as one of the
   attribute syntaxes specified in the subsection title for the
   attribute.  In addition, the value of an attribute in a response (but
   not in a request) MAY be one of the "out-of-band" values
   (Section 5.1.1) whose special encoding rules are defined in the
   Encoding and Transport document [RFC8010].





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   All attributes in a request MUST have one or more values as defined
   in Sections 5.2, 5.3, and 5.4.  All attributes in a response MUST
   have either (1) one or more values as defined in Sections 5.2, 5.3,
   and 5.4 or (2) a single "out-of-band" value.

   Most attributes are defined to have a single attribute syntax.
   However, a few attributes (e.g., "job-sheet", "media",
   "job-hold-until") are defined to have several attribute syntaxes,
   depending on the value.  These multiple attribute syntaxes are
   separated by the "|" character in the subsection title to indicate
   the choice.  Since each value MUST be tagged as to its attribute
   syntax in the protocol, a single-valued attribute instance can have
   any one of its attribute syntaxes and a multi-valued attribute
   instance can have a mixture of its defined attribute syntaxes.

5.1.1.  Out-of-Band Values - 'unknown', 'unsupported', and 'no-value'

   This document defines three "out-of-band" values that are used in
   place of an attribute's defined syntax:

   o  'unknown': The attribute is supported by the IPP object, but the
      value is unknown to the IPP object for some reason.  This
      out-of-band value is used for attributes that have an intrinsic,
      physical value that cannot be determined by the IPP object at a
      given time, e.g., sheet count, geo-location, etc.

   o  'unsupported': The attribute is unsupported by the IPP object.
      This value MUST be returned only as the value of an attribute in
      the Unsupported Attributes group.

   o  'no-value': The attribute is supported by the Printer, but the
      Administrator has not yet configured a value.

5.1.2.  'text'

   A 'text' attribute is an attribute whose value is a sequence of zero
   or more characters encoded in a maximum of 1023 ('MAX') octets.  MAX
   is the maximum length for each value of any 'text' attribute.
   However, if an attribute will always contain values whose maximum
   length is much less than MAX, the definition of that attribute will
   include a qualifier that defines the maximum length for values of
   that attribute.  For example, the "printer-location" attribute is
   specified as "printer-location (text(127))".  In this case, text
   values for "printer-location" MUST NOT exceed 127 octets; if supplied
   with a longer text string via some external interface (other than the
   protocol), implementations are free to truncate to this shorter
   length limitation.




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   In this document, all 'text' attributes are defined using the 'text'
   syntax.  However, 'text' is used only for brevity; the formal
   interpretation of 'text' is 'textWithoutLanguage | textWithLanguage'.
   That is, for any attribute defined in this document using the 'text'
   attribute syntax, all IPP objects and Clients MUST support both the
   'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes.
   However, in actual usage and protocol execution, IPP objects and
   Clients accept and return only one of the two syntaxes per attribute.
   The syntax 'text' never appears "on-the-wire".

   Both 'textWithoutLanguage' and 'textWithLanguage' are needed to
   support the real-world needs of interoperability between sites and
   systems that use different natural languages as the basis for human
   communication.  Generally, one natural language applies to all 'text'
   attributes in a given request or response.  The language is indicated
   by the "attributes-natural-language" operation attribute defined in
   Section 4.1.4 or the "attributes-natural-language" Job attribute
   defined in Section 5.3.20, and there is no need to identify the
   natural language for each text string on a value-by-value basis.  In
   these cases, the attribute syntax 'textWithoutLanguage' is used for
   'text' attributes.  In other cases, the Client needs to supply or the
   Printer needs to return a text value in a natural language that is
   different from the rest of the text values in the request or
   response.  In these cases, the Client or Printer uses the attribute
   syntax 'textWithLanguage' for 'text' attributes (this is the Natural
   Language Override mechanism described in Section 4.1.4).

   The 'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes
   are described in more detail in the following sections.

5.1.2.1.  'textWithoutLanguage'

   The 'textWithoutLanguage' syntax indicates a value that is a sequence
   of zero or more characters encoded in a maximum of 1023 (MAX) octets.
   Text strings are encoded using the rules of some charset.  The
   Printer MUST support the UTF-8 charset [RFC3629] and MAY support
   additional charsets to represent 'text' values, provided that the
   charsets are registered with IANA [IANA-CS].  See Section 5.1.8 for
   the definition of the 'charset' attribute syntax, including
   restricted semantics and examples of charsets.

5.1.2.2.  'textWithLanguage'

   The 'textWithLanguage' attribute syntax is a compound attribute
   syntax consisting of two parts: a 'textWithoutLanguage' part encoded
   in a maximum of 1023 (MAX) octets plus an additional
   'naturalLanguage' (see Section 5.1.9) part that overrides the natural
   language in force.  The 'naturalLanguage' part explicitly identifies



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   the natural language that applies to the text part of that value and
   that value alone.  For any given 'text' attribute, the
   'textWithoutLanguage' part is limited to the maximum length defined
   for that 'text' attribute, and the 'naturalLanguage' part is always
   limited to 63 (additional) octets.  Using the 'textWithLanguage'
   attribute syntax rather than the normal 'textWithoutLanguage' syntax
   is the so-called "Natural Language Override mechanism" and MUST be
   supported by all IPP objects and Clients.

   If the attribute is multi-valued (1setOf text), then the
   'textWithLanguage' attribute syntax MUST be used to explicitly
   specify each attribute value whose natural language needs to be
   overridden.  Other values in a multi-valued 'text' attribute in a
   request or a response revert to the natural language of the operation
   attribute.

   In a Job Creation request, the Printer MUST accept and store with the
   Job any natural language in the "attributes-natural-language"
   operation attribute, whether the Printer supports that natural
   language or not.  Furthermore, the Printer MUST accept and store any
   'textWithLanguage' attribute value, whether the Printer supports that
   natural language or not.  These requirements are independent of the
   value of the "ipp-attribute-fidelity" operation attribute that the
   Client MAY supply.

   Example: If the Client supplies the "attributes-natural-language"
   operation attribute with the value 'en' indicating English but the
   value of the "job-name" attribute is in French, the Client MUST use
   the 'textWithLanguage' attribute syntax with the following two
   values:

      'fr': Natural Language Override indicating French

      'Rapport Mensuel': the Job name in French

   See the Encoding and Transport document [RFC8010] for the encoding of
   the two parts and a detailed example of the 'textWithLanguage'
   attribute syntax.

5.1.3.  'name'

   This syntax type is used for user-friendly strings, such as a Printer
   name, that, for humans, are more meaningful than identifiers.  Names
   are never translated from one natural language to another.  The
   'name' attribute syntax is essentially the same as 'text', including
   the REQUIRED support of UTF-8, except that the sequence of characters
   is limited so that its encoded form MUST NOT exceed 255 (MAX) octets.




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   Also, like 'text', 'name' is really an abbreviated notation for
   either 'nameWithoutLanguage' or 'nameWithLanguage'.  That is, all IPP
   objects and Clients MUST support both the 'nameWithoutLanguage' and
   'nameWithLanguage' attribute syntaxes.  However, in actual usage and
   protocol execution, IPP objects and Clients accept and return only
   one of the two syntaxes per attribute.  The syntax 'name' never
   appears "on-the-wire".

   Only the 'text' and 'name' attribute syntaxes permit the Natural
   Language Override mechanism.

   Some attributes are defined as 'type2 keyword | name'.  These
   attributes support values that are either type2 keywords or names.
   This dual-syntax mechanism enables a site Administrator to extend
   these attributes to legally include values that are locally defined
   by the site Administrator.  Such names are not registered with IANA.

5.1.3.1.  'nameWithoutLanguage'

   The 'nameWithoutLanguage' syntax indicates a value that is a sequence
   of zero or more characters encoded in a maximum of 255 (MAX) octets.

5.1.3.2.  'nameWithLanguage'

   The 'nameWithLanguage' attribute syntax is a compound attribute
   syntax consisting of two parts: a 'nameWithoutLanguage' (see
   Section 5.1.3.1) part plus an additional 'naturalLanguage' (see
   Section 5.1.9) part that overrides the natural language in force.
   The 'naturalLanguage' part explicitly identifies the natural language
   that applies to that name value and that name value alone.  For any
   given 'name' attribute, the 'nameWithoutLanguage' part is limited to
   the maximum length defined for that 'name' attribute, and the
   'naturalLanguage' part is always limited to 63 (additional) octets.
   Using the 'nameWithLanguage' attribute syntax rather than the normal
   'nameWithoutLanguage' syntax is the Natural Language Override
   mechanism and MUST be supported by all IPP objects and Clients.

   The 'nameWithLanguage' attribute syntax behaves the same as the
   'textWithLanguage' syntax.  If a name is in a language that is
   different than the rest of the object or operation, then this
   'nameWithLanguage' syntax is used rather than the generic
   'nameWithoutLanguage' syntax.

   If the attribute is multi-valued (1setOf name), then the
   'nameWithLanguage' attribute syntax MUST be used to explicitly
   specify each attribute value whose natural language needs to be





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   overridden.  Other values in a multi-valued 'name' attribute in a
   request or a response revert to the natural language of the operation
   attribute.

   In a Job Creation request, the Printer MUST accept and store with the
   Job any natural language in the "attributes-natural-language"
   operation attribute, whether the Printer supports that natural
   language or not.  Furthermore, the Printer MUST accept and store any
   'nameWithLanguage' attribute value, whether the Printer supports that
   natural language or not.  These requirements are independent of the
   value of the "ipp-attribute-fidelity" operation attribute that the
   Client MAY supply.

   Example: If the Client supplies the "attributes-natural-language"
   operation attribute with the value 'en' indicating English but the
   "printer-name" attribute is in German, the Client MUST use the
   'nameWithLanguage' attribute syntax as follows:

      'de': Natural Language Override indicating German

      'Farbdrucker': the Printer name in German

   See the Encoding and Transport document [RFC8010] for the encoding of
   the two parts and a detailed example of the 'nameWithLanguage'
   attribute syntax.

5.1.3.3.  Matching 'name' Attribute Values

   For purposes of matching two 'name' attribute values for equality,
   such as in Job validation (where a Client-supplied value for
   attribute "xxx" is checked to see if the value is among the values of
   the Printer's corresponding "xxx-supported" attribute), the following
   match rules apply:

   1.  'keyword' values never match 'name' values.

   2.  'name' ('nameWithoutLanguage' and 'nameWithLanguage') values
       match if (1) the name parts match and (2) the Associated
       Natural Language parts (see Section 4.1.4.1) match.  The matching
       rules are as follows:

       2a.  The name parts match if the two names are identical
            character by character, except that it is RECOMMENDED that
            case be ignored as defined in "i;unicode-casemap - Simple
            Unicode Collation Algorithm" [RFC5051].  For example,
            'Ajax-letter-head-white' MUST match 'Ajax-letter-head-white'
            and SHOULD match 'ajax-letter-head-white' and
            'AJAX-LETTER-HEAD-WHITE'.



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       2b.  The Associated Natural Language parts match if the shorter
            of the two meets the syntactic requirements defined in
            Section 2.1 of RFC 5646 [RFC5646] and matches (byte for
            byte, since IPP language tags are lowercase) with the
            longer.  For example, 'en' matches 'en', 'en-us', and
            'en-gb' but matches neither 'fr' nor 'e'.

5.1.4.  'keyword'

   The 'keyword' attribute syntax is a sequence of characters, of length
   1 to 255, containing only the US-ASCII [RFC20] encoded values for
   lowercase letters ("a"-"z"), digits ("0"-"9"), hyphen ("-"), dot
   ("."), and underscore ("_").  The first character MUST be a lowercase
   letter.  Furthermore, keywords MUST be in US English.

   This syntax type is used for enumerating semantic identifiers of
   entities in the abstract protocol, i.e., entities identified in this
   document.  Keywords are used as attribute names or values of
   attributes.  Unlike 'text' and 'name' attribute values, 'keyword'
   values MUST NOT use the Natural Language Override mechanism, since
   they MUST always be US-ASCII and US English.

   Keywords are for use in the protocol.  A user interface will likely
   provide a mapping between protocol keywords and displayable
   user-friendly words and phrases that are localized to the natural
   language of the user.  While the keywords specified in this document
   MAY be displayed to users whose natural language is US English, they
   MAY be mapped to other US English words for US English users, since
   the user interface is outside the scope of this document.

   In the definition for each attribute of this syntax type, the full
   set of 'keyword' values being defined for that attribute is listed.
   The IANA IPP registry will always contain the complete and current
   list of 'keyword' values for the attribute.

   When a keyword is used to represent an attribute (its name), it MUST
   be unique within the full scope of all IPP objects and attributes.
   When a keyword is used to represent a value of an attribute, it MUST
   be unique just within the scope of that attribute.  That is, the same
   keyword MUST NOT be used for two different values within the same
   attribute to mean two different semantic ideas.  However, the same
   keyword MAY be used across two or more attributes, representing









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   different semantic ideas for each attribute.  Section 7.3 describes
   how the protocol can be extended with new 'keyword' values.  Examples
   of attribute name keywords are:

      "job-name"

      "attributes-charset"

   Note: This document uses "type1" and "type2" prefixes to the
   "keyword" basic syntax to indicate different levels of review for
   extensions (see Section 7.3).

5.1.5.  'enum'

   The 'enum' attribute syntax is an enumerated integer value that is in
   the range from 1 to 2**31 - 1 (MAX).  Each value has an associated
   'keyword' name.  In the definition for each attribute of this syntax
   type, the full set of possible values for that attribute is listed.
   This syntax type is used for attributes for which there are enum
   values assigned by other standards, such as SNMP MIBs.  A number of
   attribute enum values in this document are also used for
   corresponding attributes in other standards [RFC3805].  This syntax
   type is not used for attributes to which the Administrator can assign
   values.  Section 7.4 describes how the protocol can be extended with
   new enum values.

   Enum values are for use in the protocol.  A user interface will
   provide a mapping between protocol enum values and displayable
   user-friendly words and phrases that are localized to the natural
   language of the user.  While the enum symbols specified in this
   document MAY be displayed to users whose natural language is
   US English, they MAY be mapped to other US English words for
   US English users, since the user interface is outside the scope of
   this document.

   Note: Some SNMP MIBs use '2' for 'unknown', which corresponds to the
   IPP "out-of-band" value 'unknown'.  See the description of the
   "out-of-band" values at the beginning of Section 5.1.  Therefore,
   attributes of type 'enum' typically start at '3'.

   Note: This document uses "type1" and "type2" prefixes to the "enum"
   basic syntax to indicate different levels of review for extensions
   (see Section 7.4).








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5.1.6.  'uri'

   The 'uri' attribute syntax is any valid Uniform Resource Identifier
   (URI) [RFC3986].  Most often, URIs are simply Uniform Resource
   Locators (URLs).  The maximum length of URIs used as values of IPP
   attributes is 1023 octets.  Although most other IPP attribute syntax
   types allow for only lowercase values, this attribute syntax type
   conforms to the case-sensitive and case-insensitive rules specified
   in [RFC3986].  See also [RFC3196] for a discussion of case in URIs.

5.1.7.  'uriScheme'

   The 'uriScheme' attribute syntax is a sequence of characters
   representing a URI scheme according to RFC 3986 [RFC3986].  Though
   RFC 3986 requires that the values be case insensitive, IPP requires
   all lowercase values in IPP attributes, to simplify comparing by IPP
   Clients and Printers.

   Standard values for this syntax type include the following keywords:

   o  'ipp': for IPP schemed URIs, e.g., "ipp://example.com/ipp/..."
      [RFC3510]

   o  'ipps': for IPPS schemed URIs, e.g., "ipps://example.com/ipp/..."
      [RFC7472]

   o  'http': for HTTP schemed URIs, e.g., "http://example.com/path/to/
      filename" [RFC7230]

   o  'https': for HTTPS schemed URIs, e.g.,
      "https://example.com/path/to/filename" [RFC7230]

   o  'ftp': for FTP schemed URIs, e.g., "ftp://example.com/path/to/
      filename" [RFC1738]

   o  'mailto': for SMTP schemed URIs, e.g., "mailto:user@example.com"
      [RFC6068]

   o  'file': for file schemed URIs, e.g., "file:///path/to/filename"
      [RFC1738]

   o  'urn': for Uniform Resource Name schemed URIs, e.g.,
      "urn:uuid:01234567-89ab-cdef-fedc-ba9876543210" [RFC4122]

   A Printer MAY support any URI 'scheme' that has been registered with
   IANA [IANA-MT].  The maximum length of URI 'scheme' values used to
   represent IPP attribute values is 63 octets.




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5.1.8.  'charset'

   The 'charset' attribute syntax is a standard identifier for a
   charset.  A charset is a coded character set and encoding scheme.
   Charsets are used for labeling certain Document contents, 'text'
   attribute values, and 'name' attribute values.  The syntax and
   semantics of this attribute syntax are specified in RFC 2046
   [RFC2046] and contained in the IANA "Character Sets" registry
   [IANA-CS] according to the IANA procedures [RFC2978].  Though
   RFC 2046 requires that the values be case-insensitive US-ASCII
   [RFC20], IPP requires all lowercase values in IPP attributes, to
   simplify comparing by IPP Clients and Printers.  When a character set
   in the IANA registry has more than one name (alias), the name labeled
   as "(preferred MIME name)", if present, MUST be used.

   The maximum length of 'charset' values used to represent IPP
   attribute values is 63 octets.

   Some examples are:

   o  'utf-8': ISO 10646 Universal Multiple-Octet Coded Character Set
      (UCS) [ISO10646] represented as the UTF-8 [RFC3629] transfer
      encoding scheme in which US-ASCII [RFC20] is a subset charset.

   o  'us-ascii': 7-bit American Standard Code for Information
      Interchange (ASCII) [RFC20].

   o  'iso-8859-1': 8-bit One-Byte Coded Character Set, Latin Alphabet
      No. 1 [ISO8859-1].  That standard defines a coded character set
      that is used by Latin languages in the Western Hemisphere and
      Western Europe.  US-ASCII is a subset charset.

   Some attribute descriptions MAY place additional requirements on
   charset values that can be used, such as REQUIRED values that MUST be
   supported or additional restrictions, such as requiring that the
   charset have US-ASCII as a subset charset.















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5.1.9.  'naturalLanguage'

   The 'naturalLanguage' attribute syntax is a standard identifier for a
   natural language and, optionally, a country or region.  The values
   for this syntax type are defined by RFC 5646 [RFC5646].  Though
   RFC 5646 requires that the values be case-insensitive US-ASCII, IPP
   requires all lowercase values in IPP attributes, to simplify
   comparing by IPP Clients and Printers.  Examples include:

   o  'en': for English

   o  'en-us': for US English

   o  'fr': for French

   o  'de': for German

   The maximum length of 'naturalLanguage' values used to represent IPP
   attribute values is 63 octets.

   Note: While any standard natural language identifier defined in
   RFC 5646 can be used, Clients typically only support a subset of
   these identifiers.  When comparing two identifiers or performing
   lookups, Printers SHOULD be prepared to match legacy identifiers with
   their corresponding modern equivalents and vice versa.

5.1.10.  'mimeMediaType'

   The 'mimeMediaType' attribute syntax is the Internet media type
   (sometimes called "MIME type") as defined by RFC 2046 [RFC2046] and
   registered according to the procedures of RFC 6838 [RFC6838] for
   identifying a Document format.  The value MAY include a charset
   parameter, or some other parameter, depending on the specification of
   the media type in the IANA "Media Types" registry [IANA-MT].
   Although most other IPP syntax types allow for only lowercase values,
   this syntax type allows for mixed-case values that are
   case insensitive.

   Examples are:

   o  'text/html': An HTML Document

   o  'text/plain': A plain text Document in US-ASCII (RFC 2046
      indicates that in the absence of the charset parameter MUST mean
      US-ASCII rather than simply unspecified) [RFC2046]

   o  'text/plain; charset = US-ASCII': A plain text Document in
      US-ASCII



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   o  'text/plain; charset = ISO-8859-1': A plain text Document in
      ISO 8859-1 (Latin 1) [ISO8859-1]

   o  'text/plain; charset = utf-8': A plain text Document in ISO 10646
      represented as UTF-8 [RFC3629]

   o  'application/postscript': A PostScript Document [RFC2046]

   o  'application/vnd.hp-PCL': A PCL Document [IANA-MT] (charset escape
      sequence embedded in the Document data)

   o  'application/pdf': Portable Document Format [ISO32000]

   o  'application/octet-stream': Auto-sense - see Section 5.1.10.1

   The maximum length of a 'mimeMediaType' value to represent IPP
   attribute values is 255 octets.

5.1.10.1.  'application/octet-stream' - Auto-Sensing the Document Format

   One special type is 'application/octet-stream'.  If the Printer
   supports this value, the Printer MUST be capable of auto-sensing the
   format of the Document data using an implementation-dependent method
   that examines some number of octets of the Document data, either as
   part of the Job Creation request and/or at Document processing time.
   During auto-sensing, a Printer can determine that the Document data
   has a format that the Printer doesn't recognize.  If the Printer
   determines this problem before returning an operation response, it
   rejects the request and returns the
   'client-error-document-format-not-supported' status-code.  If the
   Printer determines this problem after accepting the request and
   returning an operation response with one of the successful
   status-code values, the Printer adds the
   'unsupported-document-format' value to the Job's "job-state-reasons"
   attribute.

   If the Printer's default value attribute "document-format-default" is
   set to 'application/octet-stream', the Printer not only supports
   auto-sensing of the Document format but will depend on the result of
   applying its auto-sensing when the Client does not supply the
   "document-format" attribute.  If the Client supplies a Document
   format value, the Printer MUST rely on the supplied attribute, rather
   than trust its auto-sensing algorithm.  To summarize:

   1.  If the Client does not supply a Document format value, the
       Printer MUST rely on its default value setting (which can be
       'application/octet-stream' indicating an auto-sensing mechanism).




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   2.  If the Client supplies a value other than
       'application/octet-stream', the Client is supplying valid
       information about the format of the Document data and the Printer
       MUST trust the Client-supplied value more than the outcome of
       applying an automatic format detection mechanism.  For example,
       the Client can request the printing of a PostScript file as a
       'text/plain' Document.  The Printer MUST print a text
       representation of the PostScript commands rather than interpret
       the stream of PostScript commands and print the result.

   3.  If the Client supplies a value of 'application/octet-stream', the
       Client is indicating that the Printer MUST use its auto-sensing
       mechanism on the Client-supplied Document data whether
       auto-sensing is the Printer's default or not.

   Note: Since the auto-sensing algorithm is probabilistic, if the
   Client requests both auto-sensing ("document-format" set to
   'application/octet-stream') and true fidelity
   ("ipp-attribute-fidelity" set to 'true'), the Printer might not be
   able to guarantee exactly what the End User intended (the
   auto-sensing algorithm might mistake one Document format for
   another), but it is able to guarantee that its auto-sensing mechanism
   will be used.

5.1.11.  'octetString'

   The 'octetString' attribute syntax is a sequence of octets encoded in
   a maximum of 1023 octets that is indicated in syntax definitions
   using the notation 'octetString(MAX)'.  This syntax type is used for
   opaque data.

5.1.12.  'boolean'

   The 'boolean' attribute syntax has only two values: 'true' and
   'false'.

5.1.13.  'integer'

   The 'integer' attribute syntax is an integer value that is in the
   range from -2**31 (MIN) to 2**31 - 1 (MAX).  Each individual
   attribute can specify the range constraint explicitly if the range is
   different from the full range of possible integer values -- for
   example, job-priority (integer(1:100)) for the "job-priority"
   attribute, as shown in the title of Section 5.2.1.  However, the
   enforcement of that additional constraint is up to the IPP objects,
   not the protocol.





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5.1.14.  'rangeOfInteger'

   The 'rangeOfInteger' attribute syntax is an ordered pair of integers
   that defines an inclusive range of integer values.  The first integer
   specifies the lower bound, and the second specifies the upper bound.
   If a range constraint is specified in the attribute definition, i.e.,
   'rangeOfInteger(X:Y)' indicating X as a minimum value and Y as a
   maximum value, then the constraint applies to both integers.

5.1.15.  'dateTime'

   The 'dateTime' attribute syntax is a standard, fixed-length, 11-octet
   representation of the "DateAndTime" syntax as defined in RFC 2579
   [RFC2579].  RFC 2579 also identifies an 8-octet representation of a
   "DateAndTime" value, but IPP objects MUST use the 11-octet
   representation.  A user interface will provide a mapping between
   protocol dateTime values and displayable user-friendly words or
   presentation values and phrases that are localized to the natural
   language and date format of the user, including time zone.

5.1.16.  'resolution'

   The 'resolution' attribute syntax specifies a two-dimensional
   resolution in the indicated units.  It consists of three values: a
   cross-feed direction resolution (positive integer value), a feed
   direction resolution (positive integer value), and a units value.
   The semantics of these three components are taken from the suggested
   values in the Printer MIB [RFC3805].  That is, the cross-feed
   direction resolution component is the same as the
   prtMarkerAddressabilityXFeedDir object in the Printer MIB, the feed
   direction resolution component is the same as the
   prtMarkerAddressabilityFeedDir in the Printer MIB, and the units
   component is the same as the prtMarkerAddressabilityUnit object in
   the Printer MIB (namely, '3' indicates dots per inch and '4'
   indicates dots per centimeter).  All three values MUST be present
   even if the first two values are the same.  For example, '300',
   '600', '3' indicates a 300-dpi cross-feed direction resolution and a
   600-dpi feed direction resolution, since a '3' indicates dots per
   inch (dpi).

5.1.17.  'collection'

   The 'collection' attribute syntax is a container holding one or more
   named values (i.e., attributes), which are called "member
   attributes".  Each 'collection' attribute definition Document lists
   the mandatory and optional member attributes of each collection
   value.  A collection value is similar to an IPP attribute group in a




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   request or a response, such as the Operation Attributes group -- they
   both consist of a set of attributes.  Collections can also be nested,
   i.e., a collection in a collection.

   A collection value consists of three separate components:

   o  A 'begCollection' value with an optional octet string value
      starting the collection,

   o  Zero or more member attributes defined using a series of unnamed
      values starting with a 'memberAttrName' value that specifies the
      member attribute name, and

   o  An 'endCollection' value with an optional name plus octet string
      value finishing the collection.

5.1.18.  '1setOf X'

   The '1setOf X' attribute syntax is one or more values of attribute
   syntax type X.  This syntax type is used for multi-valued attributes.
   The syntax type is called '1setOf' rather than just 'setOf' as a
   reminder that the set of values MUST NOT be empty (i.e., a set of
   size 0).  Sets are normally unordered; however, each attribute
   description of this type can specify that the values MUST be in a
   certain order for that attribute.

5.2.  Job Template Attributes

   Job Template attributes describe Job processing intent.  Clients MAY
   supply (in Job Creation requests) and Printers SHOULD support Job
   Template attributes.  See Section 2.3.11 for a description of support
   for OPTIONAL attributes.

   Job Template attributes conform to the following rules.  For each Job
   Template attribute called "xxx":

   1.  If the Printer supports "xxx", then it MUST support both an
       "xxx-default" attribute (unless there is a "No" in Table 8 below)
       and an "xxx-supported" attribute.  If the Printer doesn't support
       "xxx", then it MUST support neither an "xxx-default" attribute
       nor an "xxx-supported" attribute, and it MUST treat an attribute
       "xxx" supplied by a Client as unsupported.  An attribute "xxx"
       can be supported for some Document formats and not supported for
       other Document formats.  For example, it is expected that a
       Printer would only support "orientation-requested" for some
       Document formats (such as 'text/plain' or 'text/html') but not
       others (such as 'application/postscript').




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   2.  Clients MAY supply "xxx" in a Job Creation request.  If "xxx" is
       supplied, the Client is indicating a desired Job processing
       behavior for this Job.  When "xxx" is not supplied, the Client is
       indicating that the Printer apply its default Job processing
       behavior at Job processing time if the Document content does not
       contain an embedded instruction indicating an xxx-related
       behavior.

       Since an Administrator MAY change the default value attribute
       after a Job has been submitted but before it has been processed,
       the default value used by the Printer at Job processing time can
       be different than the default value in effect at Job submission
       time.

   3.  The "xxx-supported" attribute is a Printer attribute that
       describes which Job processing behaviors are supported by that
       Printer.  A Client can query the Printer to find out what
       xxx-related behaviors are supported by inspecting the returned
       values of the "xxx-supported" attribute.

       Note: The "xxx" in each "xxx-supported" attribute name is
       singular, even though an "xxx-supported" attribute usually has
       more than one value, such as "print-quality-supported", unless
       the "xxx" Job Template attribute is plural, such as "finishings"
       or "sides".  In such cases, the "xxx-supported" attribute names
       are "finishings-supported" and "sides-supported".

   4.  The "xxx-default" default value attribute describes what will be
       done at Job processing time when no other Job processing
       information is supplied by the Client (either explicitly as an
       IPP attribute in the Job Creation request or implicitly as an
       embedded instruction within the Document data).

   If an application wishes to present an End User with a list of
   supported values from which to choose, the application SHOULD query
   the Printer for its supported value attributes.  The application
   SHOULD also query the default value attributes.  If the application
   then limits selectable values to only those values that are
   supported, the application can guarantee that the values supplied by
   the Client in the Job Creation request all fall within the set of
   supported values at the Printer.  When querying the Printer, the
   Client MAY enumerate each attribute by name in the
   Get-Printer-Attributes request, or the Client MAY just name the
   "job-template" group in order to get the complete set of supported
   attributes (both supported and default attributes).






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   The "finishings" attribute is an example of a Job Template attribute.
   It can take on a set of values such as '4' ('staple'), '5' ('punch'),
   and/or '6' ('cover'); see Table 10 in Section 5.2.6.  A Client can
   query the Printer for the "finishings-supported" attribute and the
   "finishings-default" attribute.  The supported attribute contains a
   set of supported values.  The default value attribute contains the
   finishing value(s) that will be used for a new Job if the Client does
   not supply a "finishings" attribute in the Job Creation request and
   the Document data does not contain any corresponding finishing
   instructions.  If the Client does supply the "finishings" attribute
   in the Job Creation request, the Printer validates the value or
   values to make sure that they are a subset of the supported values
   identified in the Printer's "finishings-supported" attribute.  See
   Section 4.1.7.

   Table 8 below summarizes the names and relationships for all Job
   Template attributes.  The first column of the table (labeled "Job
   Attribute") shows the name and syntax for each Job Template attribute
   in the Job.  These are the attributes that can optionally be supplied
   by the Client in a Job Creation request.  The last two columns
   (labeled "Printer: Default Value Attribute" and "Printer: "Supported
   Values" Attribute") show the name and syntax for each Job Template
   attribute in the Printer (the default value attributes and the
   "supported values" attributes).  A "No" in the table means the
   Printer MUST NOT support the attribute (that is, the attribute is
   simply not applicable).  For brevity in the table, the 'text' and
   'name' entries do not show the maximum length for each attribute.

   +------------------+----------------------+-------------------------+
   | Job Attribute    | Printer: Default     | Printer: "Supported     |
   |                  | Value Attribute      | Values" Attribute       |
   +------------------+----------------------+-------------------------+
   | job-priority     | job-priority-default | job-priority-supported  |
   | (integer 1:100)  | (integer 1:100)      | (integer 1:100)         |
   +------------------+----------------------+-------------------------+
   | job-hold-until   | job-hold-until-      | job-hold-until-         |
   | (type2 keyword | | default (type2       | supported (1setOf       |
   | name)            | keyword | name)      | (type2 keyword | name)) |
   +------------------+----------------------+-------------------------+
   | job-sheets       | job-sheets-default   | job-sheets-supported    |
   | (type2 keyword | | (type2 keyword |     | (1setOf (type2 keyword  |
   | name)            | name)                | | name))                |
   +------------------+----------------------+-------------------------+
   | multiple-        | multiple-document-   | multiple-document-      |
   | document-        | handling-default     | handling-supported      |
   | handling (type2  | (type2 keyword)      | (1setOf type2 keyword)  |
   | keyword)         |                      |                         |




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   +------------------+----------------------+-------------------------+
   | copies           | copies-default       | copies-supported        |
   | (integer(1:MAX)) | (integer(1:MAX))     | (rangeOfInteger(1:MAX)) |
   +------------------+----------------------+-------------------------+
   | finishings       | finishings-default   | finishings-supported    |
   | (1setOf type2    | (1setOf type2 enum)  | (1setOf type2 enum)     |
   | enum)            |                      |                         |
   +------------------+----------------------+-------------------------+
   | page-ranges      | No                   | page-ranges-supported   |
   | (1setOf          |                      | (boolean)               |
   | rangeOfInteger   |                      |                         |
   | (1:MAX))         |                      |                         |
   +------------------+----------------------+-------------------------+
   | sides (type2     | sides-default (type2 | sides-supported (1setOf |
   | keyword)         | keyword)             | type2 keyword)          |
   +------------------+----------------------+-------------------------+
   | number-up        | number-up-default    | number-up-supported     |
   | (integer(1:MAX)) | (integer(1:MAX))     | (1setOf                 |
   |                  |                      | (integer(1:MAX) |       |
   |                  |                      | rangeOfInteger(1:MAX))) |
   +------------------+----------------------+-------------------------+
   | orientation-     | orientation-         | orientation-requested-  |
   | requested (type2 | requested-default    | supported (1setOf type2 |
   | enum)            | (type2 enum)         | enum)                   |
   +------------------+----------------------+-------------------------+
   | media (type2     | media-default (type2 | media-supported (1setOf |
   | keyword | name)  | keyword | name)      | (type2 keyword | name)) |
   |                  |                      | media-ready (1setOf     |
   |                  |                      | (type2 keyword | name)) |
   +------------------+----------------------+-------------------------+
   | printer-         | printer-resolution-  | printer-resolution-     |
   | resolution       | default (resolution) | supported (1setOf       |
   | (resolution)     |                      | resolution)             |
   +------------------+----------------------+-------------------------+
   | print-quality    | print-quality-       | print-quality-supported |
   | (type2 enum)     | default (type2 enum) | (1setOf type2 enum)     |
   +------------------+----------------------+-------------------------+

                     Table 8: Job Template Attributes

5.2.1.  job-priority (integer(1:100))

   This attribute specifies a priority for scheduling the Job.  A higher
   value specifies a higher priority.  The value 1 indicates the lowest
   possible priority.  The value 100 indicates the highest possible
   priority.  Among those Jobs that are ready to print, a Printer MUST
   print all Jobs with a priority value of n before printing those with
   a priority value of n - 1 for all n.



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   If the Printer supports this attribute, it MUST always support the
   full range from 1 to 100.  No administrative restrictions are
   permitted.  This way, an End User can always make full use of the
   entire range with any Printer.  If privileged Jobs are implemented
   outside IPP, they MUST have priorities higher than 100, rather than
   restricting the range available to End Users.

   If the Client does not supply this attribute and this attribute is
   supported by the Printer, the Printer MUST use the value of the
   Printer's "job-priority-default" attribute at Job submission time
   (unlike most Job Template attributes that are used if necessary at
   Job processing time).

   The syntax for the "job-priority-supported" attribute is also
   integer(1:100).  This single integer value indicates the number of
   priority levels supported.  The Printer MUST take the value supplied
   by the Client and map it to the closest integer in a sequence of
   n integer values that are evenly distributed over the range from
   1 to 100 using the formula:

      roundToNearestInt((100x + 50) / n)

   where n is the value of "job-priority-supported" and x ranges from
   0 through (n - 1).

   For example, if n = 1, the sequence of values is 50; if n = 2, the
   sequence of values is 25 and 75; if n = 3, the sequence of values is
   17, 50, and 83; if n = 10, the sequence of values is 5, 15, 25, 35,
   45, 55, 65, 75, 85, and 95; if n = 100, the sequence of values is
   1, 2, 3, ... 100.





















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   Table 9 shows how a Printer maps Client-supplied "job-priority"
   values for example values of n.

                 +--------------+-------+-------+--------+
                 | job-priority | n = 1 | n = 2 | n = 10 |
                 +--------------+-------+-------+--------+
                 | 1            | 50    | 17    | 5      |
                 +--------------+-------+-------+--------+
                 | 10           | 50    | 17    | 5      |
                 +--------------+-------+-------+--------+
                 | 20           | 50    | 17    | 15     |
                 +--------------+-------+-------+--------+
                 | 30           | 50    | 17    | 25     |
                 +--------------+-------+-------+--------+
                 | 40           | 50    | 50    | 35     |
                 +--------------+-------+-------+--------+
                 | 50           | 50    | 50    | 45     |
                 +--------------+-------+-------+--------+
                 | 60           | 50    | 50    | 55     |
                 +--------------+-------+-------+--------+
                 | 70           | 50    | 50    | 65     |
                 +--------------+-------+-------+--------+
                 | 80           | 50    | 83    | 75     |
                 +--------------+-------+-------+--------+
                 | 90           | 50    | 83    | 85     |
                 +--------------+-------+-------+--------+
                 | 100          | 50    | 83    | 95     |
                 +--------------+-------+-------+--------+

                      Table 9: "job-priority" Values

5.2.2.  job-hold-until (type2 keyword | name(MAX))

   This attribute specifies the named time period during which the Job
   MUST become a candidate for printing.

   Standard 'keyword' values for named time periods are:

   o  'no-hold': immediately, if there are no other reasons to hold
      the job

   o  'indefinite': the Job is held indefinitely, until a Client
      performs a Release-Job (Section 4.3.6)

   o  'day-time': during the day

   o  'evening': evening




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   o  'night': night

   o  'weekend': weekend

   o  'second-shift': second shift (after close of business)

   o  'third-shift': third shift (after midnight)

   An Administrator MUST associate allowable print times with a named
   time period (by means outside the scope of this IPP/1.1 document).
   An Administrator is encouraged to pick names that suggest the type of
   time period.  An Administrator MAY define additional values using the
   'name' or 'keyword' attribute syntax, depending on implementation.

   If the value of this attribute specifies a time period that is in the
   future, the Printer SHOULD add the "job-hold-until-specified" value
   to the Job's "job-state-reasons" attribute, MUST move the Job to the
   'pending-held' state, and MUST NOT schedule the Job for printing
   until the specified time period arrives.

   When the specified time period arrives, the Printer MUST remove the
   "job-hold-until-specified" value from the Job's "job-state-reasons"
   attribute, if present.  If there are no other Job state reasons that
   keep the Job in the 'pending-held' state, the Printer MUST consider
   the Job as a candidate for processing by moving the Job to the
   'pending' state.

   If this Job attribute value is the named value 'no-hold' or the
   specified time period has already started, the Job MUST be a
   candidate for processing immediately.

   If the Client does not supply this attribute and this attribute is
   supported by the Printer, the Printer MUST use the value of the
   Printer's "job-hold-until-default" at Job submission time (unlike
   most Job Template attributes that are used if necessary at Job
   processing time).

5.2.3.  job-sheets (type2 keyword | name(MAX))

   This attribute determines which Job start/end sheet(s), if any, MUST
   be printed with a Job.

   Standard 'keyword' values are:

   o  'none': no Job sheet is printed

   o  'standard': one or more site-specific standard Job sheets are
      printed, e.g., a single start sheet or both start and end sheets



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   An Administrator MAY define additional values using the 'name' or
   'keyword' attribute syntax, depending on implementation.

   The effect of this attribute on Jobs with multiple Documents MAY be
   affected by the "multiple-document-handling" Job attribute
   (Section 5.2.4), depending on the Job sheet semantics.

5.2.4.  multiple-document-handling (type2 keyword)

   This RECOMMENDED attribute controls which Impressions and Media
   Sheets constitute a Set for copy generation and finishing processes.
   When the value of the "copies" attribute exceeds '1', it also
   controls the order in which the copies that result from processing
   the Documents are produced.  For the purposes of this explanation, if
   "a" represents an instance of Document data, then the result of
   processing the data in Document "a" is a sequence of Media Sheets
   represented by "a(*)".  This attribute MUST be supported with at
   least one value if the Printer supports multiple Documents per Job
   (see Sections 4.2.4 and 4.3.1).

   Standard 'keyword' values are:

   o  'single-document': If a Job has multiple Documents, say, the
      Document data is called "a" and "b", then the result of processing
      all the Document data (a and then b) MUST be treated as a single
      sequence of Media Sheets for finishing processes; that is,
      finishing is performed on the concatenation of the sequences
      a(*),b(*).  The Printer MUST NOT force the data in each Document
      instance to be formatted onto a new Impression, nor to start a new
      Impression on a new Media Sheet.  If more than one copy is made,
      the ordering of the sets of Media Sheets resulting from processing
      the Document data MUST be a(*), b(*), a(*), b(*), ..., and the
      Printer MUST force each copy (a(*),b(*)) to start on a new Media
      Sheet.

   o  'separate-documents-uncollated-copies': If a Job has multiple
      Documents, say, the Document data is called "a" and "b", then the
      result of processing the data in each Document instance MUST be
      treated as a single sequence of Media Sheets for finishing
      processes; that is, the sets a(*) and b(*) would each be finished
      separately.  The Printer MUST force each copy of the result of
      processing the data in a single Document to start on a new Media
      Sheet.  If more than one copy is made, the ordering of the sets of
      Media Sheets resulting from processing the Document data MUST be
      a(*), a(*), ..., b(*), b(*), ... .






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   o  'separate-documents-collated-copies': If a Job has multiple
      Documents, say, the Document data is called "a" and "b", then the
      result of processing the data in each Document instance MUST be
      treated as a single sequence of Media Sheets for finishing
      processes; that is, the sets a(*) and b(*) would each be finished
      separately.  The Printer MUST force each copy of the result of
      processing the data in a single Document to start on a new Media
      Sheet.  If more than one copy is made, the ordering of the sets of
      Media Sheets resulting from processing the Document data MUST be
      a(*), b(*), a(*), b(*), ... .

   o  'single-document-new-sheet': Same as 'single-document', except
      that the Printer MUST ensure that the first Impression of each
      Document instance in the Job is placed on a new Media Sheet.  This
      value allows multiple Documents to be stapled together with a
      single staple where each Document starts on a new Media Sheet.

   The 'single-document' value is the same as
   'separate-documents-collated-copies' with respect to the ordering of
   Input Pages, but not Media Sheet generation, since 'single-document'
   will put the first page of the next Document on the back side of a
   Media Sheet if an odd number of pages have been produced so far for
   the Job, while 'separate-documents-collated-copies' always forces the
   next Document or Document copy on to a new Media Sheet.  In addition,
   if the "finishings" attribute specifies 'staple', then with
   'single-document', Documents a and b are stapled together as a single
   Set with no regard to a new Media Sheet, while with
   'single-document-new-sheet', Documents a and b are stapled together
   as a single Set but Document b starts on a new Media Sheet.  With
   'separate-documents-uncollated-copies' and
   'separate-documents-collated-copies', Documents a and b are stapled
   separately.

   Note: The value 'separate-documents-uncollated-copies' produces
   uncollated Media Sheets within a Set, e.g., when "copies" is '2' a
   two-Document Job will be printed as Media Sheets a(1), a(1), a(2),
   a(2), ... a(n), a(n), b(1), b(1), ..., b(n), b(n).  All other values
   produce collated Media Sheets within a Set.

   The relationship of this attribute and the other attributes that
   control Document processing is described in Appendix C.3.










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5.2.5.  copies (integer(1:MAX))

   This RECOMMENDED attribute specifies the number of copies to be
   printed.

   On many devices, the supported number of collated copies will be
   limited by the number of physical output bins on the device and can
   be different from the number of uncollated copies that can be
   supported.

   Note: The effect of this attribute on Jobs with multiple Documents is
   controlled by the "multiple-document-handling" Job attribute
   (Section 5.2.4).  The relationship of this attribute and the other
   attributes that control Document processing is described in
   Appendix C.3.

5.2.6.  finishings (1setOf type2 enum)

   This RECOMMENDED attribute identifies the finishing processes that
   the Printer uses for each copy of each printed Document in the Job.
   For Jobs with multiple Documents, the "multiple-document-handling"
   attribute determines what constitutes a "copy" for purposes of
   finishing.

   Standard enum values defined in this document are listed in Table 10.
   The 'staple-xxx' values are specified with respect to the Document as
   if the Document were in portrait orientation with the origin of each
   Media Sheet at the top left corner.  If the Document is actually in
   landscape or reverse-landscape orientation, the Client supplies the
   appropriate transformed value.  For example, to position a staple in
   the upper left-hand corner of a landscape Document when held for
   reading, the Client supplies the 'staple-bottom-left' value, since
   landscape is defined as a +90 degree rotation of the image with
   respect to the media from portrait, i.e., counterclockwise.  On the
   other hand, to position a staple in the upper left-hand corner of a
   reverse-landscape Document when held for reading, the Client supplies
   the 'staple-top-right' value, since reverse-landscape is defined as
   a -90 degree rotation of the image with respect to the media from
   portrait, i.e., clockwise.

   The angle (vertical, horizontal, angled) of each staple with respect
   to the Document depends on the implementation, which can in turn
   depend on the value of the attribute.








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   Note: The effect of this attribute on Jobs with multiple Documents is
   controlled by the "multiple-document-handling" Job attribute
   (Section 5.2.4).  The relationship of this attribute and the other
   attributes that control Document processing is described in
   Appendix C.3.

   Note: The value of '3' ('none') has no effect when combined with any
   other values.

   Note: The "finishings-col" attribute [PWG5100.1] is an alternative to
   the "finishings" attribute that allows the Client to specify
   finishing intent in greater detail.

   +-----------+-------------------------------------------------------+
   | Value     | Symbolic Name and Description                         |
   +-----------+-------------------------------------------------------+
   | '3'       | 'none': Perform no finishing.                         |
   +-----------+-------------------------------------------------------+
   | '4'       | 'staple': Bind the Document(s) with one or more       |
   |           | staples.  The exact number and placement of the       |
   |           | staples are site defined.                             |
   +-----------+-------------------------------------------------------+
   | '5'       | 'punch': This value indicates that holes are required |
   |           | in the finished Document.  The exact number and       |
   |           | placement of the holes are site defined.  The punch   |
   |           | specification MAY be satisfied (in a site-specific    |
   |           | and implementation-specific manner) either by         |
   |           | drilling/punching or by substituting pre-drilled      |
   |           | media.                                                |
   +-----------+-------------------------------------------------------+
   | '6'       | 'cover': This value is specified when it is desired   |
   |           | to select a non-printed (or pre-printed) cover for    |
   |           | the Document.  This does not supplant the             |
   |           | specification of a printed cover (on cover stock      |
   |           | medium) by the Document itself.                       |
   +-----------+-------------------------------------------------------+
   | '7'       | 'bind': This value indicates that a binding is to be  |
   |           | applied to the Document; the type and placement of    |
   |           | the binding are site defined.                         |
   +-----------+-------------------------------------------------------+
   | '8'       | 'saddle-stitch': Bind the Document(s) with one or     |
   |           | more staples (wire stitches) along the middle fold.   |
   |           | The exact number and placement of the staples and the |
   |           | middle fold are implementation defined and/or site    |
   |           | defined.                                              |






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   +-----------+-------------------------------------------------------+
   | '9'       | 'edge-stitch': Bind the Document(s) with one or more  |
   |           | staples (wire stitches) along one edge.  The exact    |
   |           | number and placement of the staples are               |
   |           | implementation defined and/or site defined.           |
   +-----------+-------------------------------------------------------+
   | '10'-'19' | reserved for future generic finishing enum values.    |
   +-----------+-------------------------------------------------------+
   | '20'      | 'staple-top-left': Bind the Document(s) with one or   |
   |           | more staples in the top left corner.                  |
   +-----------+-------------------------------------------------------+
   | '21'      | 'staple-bottom-left': Bind the Document(s) with one   |
   |           | or more staples in the bottom left corner.            |
   +-----------+-------------------------------------------------------+
   | '22'      | 'staple-top-right': Bind the Document(s) with one or  |
   |           | more staples in the top right corner.                 |
   +-----------+-------------------------------------------------------+
   | '23'      | 'staple-bottom-right': Bind the Document(s) with one  |
   |           | or more staples in the bottom right corner.           |
   +-----------+-------------------------------------------------------+
   | '24'      | 'edge-stitch-left': Bind the Document(s) with one or  |
   |           | more staples (wire stitches) along the left edge.     |
   |           | The exact number and placement of the staples are     |
   |           | implementation defined and/or site defined.           |
   +-----------+-------------------------------------------------------+
   | '25'      | 'edge-stitch-top': Bind the Document(s) with one or   |
   |           | more staples (wire stitches) along the top edge.  The |
   |           | exact number and placement of the staples are         |
   |           | implementation defined and/or site defined.           |
   +-----------+-------------------------------------------------------+
   | '26'      | 'edge-stitch-right': Bind the Document(s) with one or |
   |           | more staples (wire stitches) along the right edge.    |
   |           | The exact number and placement of the staples are     |
   |           | implementation defined and/or site defined.           |
   +-----------+-------------------------------------------------------+
   | '27'      | 'edge-stitch-bottom': Bind the Document(s) with one   |
   |           | or more staples (wire stitches) along the bottom      |
   |           | edge.  The exact number and placement of the staples  |
   |           | are implementation defined and/or site defined.       |
   +-----------+-------------------------------------------------------+
   | '28'      | 'staple-dual-left': Bind the Document(s) with two     |
   |           | staples (wire stitches) along the left edge, assuming |
   |           | a portrait Document (see above).                      |








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   +-----------+-------------------------------------------------------+
   | '29'      | 'staple-dual-top': Bind the Document(s) with two      |
   |           | staples (wire stitches) along the top edge, assuming  |
   |           | a portrait Document (see above).                      |
   +-----------+-------------------------------------------------------+
   | '30'      | 'staple-dual-right': Bind the Document(s) with two    |
   |           | staples (wire stitches) along the right edge,         |
   |           | assuming a portrait Document (see above).             |
   +-----------+-------------------------------------------------------+
   | '31'      | 'staple-dual-bottom': Bind the Document(s) with two   |
   |           | staples (wire stitches) along the bottom edge,        |
   |           | assuming a portrait Document (see above).             |
   +-----------+-------------------------------------------------------+

                    Table 10: "finishings" Enum Values

5.2.7.  page-ranges (1setOf rangeOfInteger(1:MAX))

   This RECOMMENDED attribute identifies the range(s) of Input Pages
   that the Printer uses for each Set to be printed prior to imposition
   of those pages onto Impressions.  Nothing is printed for any pages
   identified that do not exist in the Set/Document(s).  Ranges MUST be
   in ascending order (1-3, 5-7, 15-19, etc.) and MUST NOT overlap so
   that a non-spooling Printer can process the Job in a single pass.  If
   the ranges are not ascending or are overlapping, the Printer MUST
   reject the request and return the 'client-error-bad-request'
   status-code.  The attribute is associated with Input Pages and not
   application-numbered pages such as the page numbers found in the
   headers and/or footers for certain word processing applications.

   For Jobs with multiple Documents, the "multiple-document-handling"
   attribute determines what constitutes a Set for purposes of the
   specified page range(s).  When "multiple-document-handling" is
   'single-document', the Printer MUST apply each supplied page range
   once to the concatenation of the Input Pages.  For example, if there
   are 8 Documents of 10 pages each, the page range '41-60' prints the
   pages in the 5th and 6th Documents as a single Document, and none of
   the pages of the other Documents are printed.  When
   "multiple-document-handling" is
   'separate-documents-uncollated-copies' or
   'separate-documents-collated-copies', the Printer MUST apply each
   supplied page range repeatedly to each Document copy.  For the same
   Job, the page range '1-3, 10-10' would print the first 3 pages
   and the 10th page of each of the 8 Documents in the Job, as 8
   separate Sets.






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   "page-ranges-supported" is a boolean value indicating whether the
   Printer is capable of supporting the printing of page ranges.  This
   capability can differ from one PDL to another.  There is no
   "page-ranges-default" attribute.  If the "page-ranges" attribute is
   not supplied by the Client, all pages of the Document are printed.

   Note: In many cases, the Client supplies only those Input Pages that
   need to be printed in the Document data, and the "page-ranges" Job
   Template attribute is not used.  However, Clients that submit
   already-generated Document data (either static content from some web
   site or previously submitted content the End User wishes to reprint)
   can use this attribute to print just a subset of the pages contained
   in the Document.  In this case, if a "page-ranges" value of 'n-m' is
   specified, the first page to be printed will be page n.  All
   subsequent pages of the Document will be printed through and
   including page m.

   Note: The effect of this attribute on Jobs with multiple Documents is
   controlled by the "multiple-document-handling" Job attribute
   (Section 5.2.4).  The relationship of this attribute and the other
   attributes that control Document processing is described in
   Appendix C.3.

5.2.8.  sides (type2 keyword)

   This RECOMMENDED attribute specifies how Impressions are placed upon
   the sides of a Media Sheet.

   The standard 'keyword' values are:

   o  'one-sided': imposes each consecutive Impression upon the same
      side of consecutive Media Sheets.

   o  'two-sided-long-edge': imposes each consecutive pair of
      Impressions upon front and back sides of consecutive Media Sheets,
      such that the orientation of each pair of Impressions on the
      medium would be correct for the reader as if for binding on the
      long edge.  This imposition is sometimes called 'duplex' or
      'head-to-head'.

   o  'two-sided-short-edge': imposes each consecutive pair of
      Impressions upon front and back sides of consecutive Media Sheets,
      such that the orientation of each pair of Impressions on the
      medium would be correct for the reader as if for binding on the
      short edge.  This imposition is sometimes called 'tumble' or
      'head-to-toe'.





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   Note: The effect of this attribute on Jobs with multiple Documents is
   controlled by the "multiple-document-handling" Job attribute
   (Section 5.2.4).  The relationship of this attribute and the other
   attributes that control Document processing is described in
   Appendix C.3.

5.2.9.  number-up (integer(1:MAX))

   This attribute specifies the number of Input Pages to impose upon a
   single Impression.  For example, if the value is:

   o  '1': the Printer MUST place one Input Page on a single Impression.

   o  '2': the Printer MUST place two Input Pages on a single
      Impression.

   o  '4': the Printer MUST place four Input Pages on a single
      Impression.

   In all cases, the Printer MAY add some sort of translation, scaling,
   or rotation of Input Pages when imposing them.

   Note: The effect of this attribute on Jobs with multiple Documents is
   controlled by the "multiple-document-handling" Job attribute
   (Section 5.2.4).  The relationship of this attribute and the other
   attributes that control Document processing is described in
   Appendix C.3.

5.2.10.  orientation-requested (type2 enum)

   This RECOMMENDED attribute indicates the desired orientation for
   printed Input Pages; it does not describe the orientation of the
   Client-supplied Input Pages.

   For some Document formats (such as 'application/postscript'), the
   desired orientation of the Input Pages is sometimes specified within
   the Document data.  This information is generated by a Printer driver
   prior to the submission of the Print Job.  Other Document formats
   such as 'text/plain' do not include the notion of desired orientation
   within the Document data.  In the latter case, it is possible for the
   Printer to bind the desired orientation to the Document data after it
   has been submitted.  Printers MAY only support
   "orientation-requested" for some Document formats (e.g., 'text/plain'
   or 'text/html') but not others (e.g., 'application/postscript').
   This is no different than any other Job Template attribute, since
   Section 5.2, item 1, points out that a Printer can support or not
   support any Job Template attribute based on the Document format




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   supplied by the Client.  However, a special mention is made here,
   since it is very likely that a Printer will support
   "orientation-requested" for only a subset of the supported Document
   formats.

   Standard enum values are listed in Table 11.

   Note: The effect of this attribute on Jobs with multiple Documents is
   controlled by the "multiple-document-handling" Job attribute
   (Section 5.2.4).  The relationship of this attribute and the other
   attributes that control Document processing is described in
   Appendix C.3.







































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   +-------+-----------------------------------------------------------+
   | Value | Symbolic Name and Description                             |
   +-------+-----------------------------------------------------------+
   | '3'   | 'portrait': The content will be imaged across the short   |
   |       | edge of the medium.                                       |
   +-------+-----------------------------------------------------------+
   | '4'   | 'landscape': The content will be imaged across the long   |
   |       | edge of the medium.  Landscape is defined to be a         |
   |       | rotation of the Input Page to be imaged by +90 degrees    |
   |       | with respect to the medium (i.e., counterclockwise) from  |
   |       | the portrait orientation.  Note: The +90 direction was    |
   |       | chosen because simple finishing on the long edge is the   |
   |       | same edge whether portrait or landscape.                  |
   +-------+-----------------------------------------------------------+
   | '5'   | 'reverse-landscape': The content will be imaged across    |
   |       | the long edge of the medium.  Reverse-landscape is        |
   |       | defined to be a rotation of the Input Page to be imaged   |
   |       | by -90 degrees with respect to the medium (i.e.,          |
   |       | clockwise) from the portrait orientation.  Note: The      |
   |       | 'reverse-landscape' value was added because some          |
   |       | applications rotate landscape -90 degrees from portrait,  |
   |       | rather than +90 degrees.                                  |
   +-------+-----------------------------------------------------------+
   | '6'   | 'reverse-portrait': The content will be imaged across the |
   |       | short edge of the medium.  Reverse-portrait is defined to |
   |       | be a rotation of the Input Page to be imaged by 180       |
   |       | degrees with respect to the medium from the portrait      |
   |       | orientation.  Note: The 'reverse-portrait' value was      |
   |       | added for use with the "finishings" attribute in cases    |
   |       | where the opposite edge is desired for finishing a        |
   |       | portrait Document on simple finishing devices that have   |
   |       | only one finishing position.  Thus, a 'text'/plain'       |
   |       | portrait Document can be stapled "on the right" by a      |
   |       | simple finishing device, as is common use with some       |
   |       | Middle Eastern languages such as Hebrew.                  |
   +-------+-----------------------------------------------------------+

               Table 11: "orientation-requested" Enum Values













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5.2.11.  media (type2 keyword | name(MAX))

   This RECOMMENDED attribute identifies the medium that the Printer
   uses for all Impressions of the Job.

   The values for "media" historically have included medium names,
   medium sizes, input trays, and electronic forms so that one attribute
   specifies the media.  However, the Client SHOULD only use the media
   attribute to specify medium sizes using PWG Media Standardized Names
   [PWG5101.1].

   If a Printer supports a medium name as a value of this attribute,
   such a medium name implicitly selects an input tray that contains the
   specified medium.  If a Printer supports a medium size as a value of
   this attribute, such a medium size implicitly selects a medium name
   that in turn implicitly selects an input tray that contains the
   medium with the specified size.  If a Printer supports an input tray
   as the value of this attribute, such an input tray implicitly selects
   the medium that is in that input tray at the time the Job prints.
   This case includes manual-feed input trays.  If a Printer supports an
   electronic form as the value of this attribute, such an electronic
   form implicitly selects a medium name that in turn implicitly selects
   an input tray that contains the medium specified by the electronic
   form.  The electronic form also implicitly selects an image that the
   Printer MUST merge with the Document data as it prints each page.

   PWG Media Standardized Names [PWG5101.1] SHOULD be used.  Legacy
   'keyword' values are taken from ISO DPA [ISO10175], the Printer MIB
   [RFC3805], and ASME-Y14.1M [ASME-Y14.1M].  An Administrator MAY
   define additional values using the 'name' or 'keyword' attribute
   syntax, depending on implementation.

   There is also an additional Printer attribute named "media-ready",
   which differs from "media-supported" in that legal values only
   include the subset of "media-supported" values that are physically
   loaded and ready for printing with no Operator intervention required.

   The relationship of this attribute and the other attributes that
   control Document processing is described in Appendix C.3.

   Note: If supported by the Printer, Clients MAY use the alternative
   "media-col" attribute [PWG5100.3] [PWG5100.13] to specify medium
   requirements in greater detail.








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5.2.12.  printer-resolution (resolution)

   This RECOMMENDED attribute identifies the output resolution that the
   Printer uses for the Job.

   Note: This attribute and the "print-quality" attribute
   (Section 5.2.13) are both used to specify the overall output quality
   of the Job.  If a Client specifies conflicting "printer-resolution"
   and "print-quality" values, Printers SHOULD use the "print-quality"
   value.

5.2.13.  print-quality (type2 enum)

   This RECOMMENDED attribute specifies the print quality that the
   Printer uses for the Job.

   The standard enum values are listed in Table 12.

   Note: This attribute and the "printer-resolution" attribute
   (Section 5.2.12) are both used to specify the overall output quality
   of the Job.  If a Client specifies conflicting "printer-resolution"
   and "print-quality" values, Printers SHOULD use the "print-quality"
   value.

    +-------+---------------------------------------------------------+
    | Value | Symbolic Name and Description                           |
    +-------+---------------------------------------------------------+
    | '3'   | 'draft': lowest quality available on the Printer        |
    +-------+---------------------------------------------------------+
    | '4'   | 'normal': normal or intermediate quality on the Printer |
    +-------+---------------------------------------------------------+
    | '5'   | 'high': highest quality available on the Printer        |
    +-------+---------------------------------------------------------+

                   Table 12: "print-quality" Enum Values

5.3.  Job Description and Status Attributes

   The attributes in this section form the attribute group called
   "job-description".  Tables 13 and 14 summarize these attributes.  The
   third column of each table indicates whether the attribute is a
   REQUIRED attribute that MUST be supported by Printers.  If it is not
   indicated as REQUIRED, then it is OPTIONAL.  The maximum size in
   octets for 'text' and 'name' attributes is indicated in parentheses.







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             +------------------+----------------+-----------+
             | Attribute        | Syntax         | REQUIRED? |
             +------------------+----------------+-----------+
             | job-impressions  | integer(0:MAX) |           |
             +------------------+----------------+-----------+
             | job-k-octets     | integer(0:MAX) |           |
             +------------------+----------------+-----------+
             | job-media-sheets | integer(1:MAX) |           |
             +------------------+----------------+-----------+
             | job-name         | name(MAX)      | REQUIRED  |
             +------------------+----------------+-----------+

             Table 13: Job Description Attributes (READ-WRITE)

   +-----------------------------+-------------------------+-----------+
   | Attribute                   | Syntax                  | REQUIRED? |
   +-----------------------------+-------------------------+-----------+
   | attributes-charset          | charset                 | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | attributes-natural-language | naturalLanguage         | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | date-time-at-completed      | dateTime|unknown|no-    |           |
   |                             | value                   |           |
   +-----------------------------+-------------------------+-----------+
   | date-time-at-creation       | dateTime|unknown        |           |
   +-----------------------------+-------------------------+-----------+
   | date-time-at-processing     | dateTime|unknown|no-    |           |
   |                             | value                   |           |
   +-----------------------------+-------------------------+-----------+
   | job-detailed-status-        | 1setOf text(MAX)        |           |
   | messages                    |                         |           |
   +-----------------------------+-------------------------+-----------+
   | job-document-access-errors  | 1setOf text(MAX)        |           |
   +-----------------------------+-------------------------+-----------+
   | job-id                      | integer(1:MAX)          | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | job-impressions-completed   | integer(0:MAX)          |           |
   +-----------------------------+-------------------------+-----------+
   | job-k-octets-processed      | integer(0:MAX)          |           |
   +-----------------------------+-------------------------+-----------+
   | job-media-sheets-completed  | integer(0:MAX)          |           |
   +-----------------------------+-------------------------+-----------+
   | job-message-from-operator   | text(127)               |           |
   +-----------------------------+-------------------------+-----------+
   | job-more-info               | uri                     |           |
   +-----------------------------+-------------------------+-----------+
   | job-originating-user-name   | name(MAX)               | REQUIRED  |




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   +-----------------------------+-------------------------+-----------+
   | job-printer-up-time         | integer(1:MAX)          | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | job-printer-uri             | uri                     | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | job-state                   | type1 enum              | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | job-state-message           | text(MAX)               |           |
   +-----------------------------+-------------------------+-----------+
   | job-state-reasons           | 1setOf type2 keyword    | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | job-uri                     | uri                     | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | number-of-documents         | integer(0:MAX)          |           |
   +-----------------------------+-------------------------+-----------+
   | number-of-intervening-jobs  | integer(0:MAX)          |           |
   +-----------------------------+-------------------------+-----------+
   | output-device-assigned      | name(127)               |           |
   +-----------------------------+-------------------------+-----------+
   | time-at-completed           | integer(MIN:MAX)        | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | time-at-creation            | integer(MIN:MAX)        | REQUIRED  |
   +-----------------------------+-------------------------+-----------+
   | time-at-processing          | integer(MIN:MAX)        | REQUIRED  |
   +-----------------------------+-------------------------+-----------+

                Table 14: Job Status Attributes (READ-ONLY)

5.3.1.  job-id (integer(1:MAX))

   This REQUIRED attribute contains the ID of the Job.  The Printer, on
   receipt of a new Job, generates an ID that identifies the new Job on
   that Printer.  The Printer returns the value of the "job-id"
   attribute as part of the response to a Job Creation request.

   For a description of this attribute and its relationship to the
   "job-uri" and "job-printer-uri" attributes, see the discussion in
   Section 3.4 ("Object Identity").

5.3.2.  job-uri (uri)

   This REQUIRED attribute contains the URI for the Job.  The Printer,
   on receipt of a new Job, generates a URI that identifies the new Job.
   The Printer returns the value of the "job-uri" attribute as part of
   the response to a Job Creation request.  The precise format of a Job
   URI is implementation dependent [RFC3510] [RFC7472].  If the Printer
   supports more than one URI and there is some relationship between the
   newly formed Job URI and the Printer's URI, the Printer uses the



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   Printer URI supplied by the Client in the Job Creation request.  For
   example, if the Job Creation request comes in over a secure channel,
   the new Job URI MUST use the same secure channel.  This can be
   guaranteed because the Printer is responsible for generating the Job
   URI and the Printer is aware of its security configuration and policy
   as well as the Printer URI used in the Job Creation request.

   For a description of this attribute and its relationship to the
   "job-id" and "job-printer-uri" attributes, see the discussion in
   Section 3.4 ("Object Identity").

5.3.3.  job-printer-uri (uri)

   This REQUIRED attribute identifies the Printer that created this Job.
   When a Printer creates a Job, it populates this attribute with the
   Printer URI that was used in the Job Creation request.  This
   attribute permits a Client to identify the Printer that created this
   Job when only the Job's URI is available to the Client.  The Client
   queries the creating Printer to determine which languages, charsets,
   and operations are supported for this Job.

   For a description of this attribute and its relationship to the
   "job-uri" and "job-id" attributes, see the discussion in Section 3.4
   ("Object Identity").

5.3.4.  job-more-info (uri)

   Similar to "printer-more-info", this attribute contains the URI
   referencing some resource with more information about this Job,
   perhaps an HTML page containing status information about the Job.

5.3.5.  job-name (name(MAX))

   This REQUIRED attribute is the name of the Job.  It is a name that is
   more user friendly than the "job-uri" or "job-id" attribute values.
   It does not need to be unique between Jobs.  The Job's "job-name"
   attribute is set to the value supplied by the Client in the
   "job-name" operation attribute in the Job Creation request (see
   Section 4.2.1.1).  If, however, the "job-name" operation attribute is
   not supplied by the Client in the Job Creation request, the Printer,
   on creation of the Job, MUST generate a name.  The Printer SHOULD
   generate the value of the Job's "job-name" attribute from the first
   of the following sources that produces a value: (1) the
   "document-name" operation attribute of the first (or only) Document,
   (2) the "document-URI" attribute of the first (or only) Document, or
   (3) any other piece of Job-specific and/or Document data.





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5.3.6.  job-originating-user-name (name(MAX))

   This REQUIRED attribute contains the name of the End User that
   submitted the Print Job.  The Printer sets this attribute to the most
   authenticated printable name that it can obtain from the
   authentication service over which the IPP operation was received.
   Only if such a name is not available does the Printer use the value
   supplied by the Client in the "requesting-user-name" operation
   attribute of the Job Creation request (see Sections 5.4.2, 5.4.3,
   and 9).

   Note: The Printer needs to keep an internal originating user ID of
   some form, typically as a credential of a principal, with the Job.
   Since such an internal attribute is implementation dependent and not
   of interest to Clients, it is not specified as a Job attribute.  This
   originating user ID is used for authorization checks (if any) on all
   subsequent operations.

5.3.7.  job-state (type1 enum)

   This REQUIRED attribute identifies the current state of the Job.
   Even though IPP defines seven values for Job states (plus the
   out-of-band 'unknown' value -- see Section 5.1), implementations only
   need to support those states that are appropriate for the particular
   implementation.  In other words, a Printer supports only those Job
   states implemented by the Output Device and available to the Printer
   implementation.

   Standard enum values are listed in Table 15.

   The final value for this attribute MUST be one of the following --
   'completed', 'canceled', or 'aborted' -- before the Printer removes
   the Job altogether.  The length of time that Jobs remain in the
   'canceled', 'aborted', and 'completed' states depends on
   implementation.  See Section 5.3.7.2.
















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   Figure 3 shows the normal Job state transitions.  Normally, a Job
   progresses from left to right.  Other state transitions are unlikely
   but are not forbidden.  Not shown are the transitions to the
   'canceled' state from the 'pending', 'pending-held', and
   'processing-stopped' states.

                                                      +----> canceled
                                                     /
       +----> pending  -------> processing ---------+------> completed
       |         ^                   ^               \
   --->+         |                   |                +----> aborted
       |         v                   v               /
       +----> pending-held    processing-stopped ---+

                       Figure 3: IPP Job Life Cycle

   Jobs reach one of the three terminal states -- 'completed',
   'canceled', or 'aborted' -- after the Jobs have completed all
   activity, including stacking output media, and all Job Status
   attributes have reached their final values for the Job.































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   +--------+----------------------------------------------------------+
   | Values | Symbolic Name and Description                            |
   +--------+----------------------------------------------------------+
   | '3'    | 'pending': The Job is a candidate to start processing    |
   |        | but is not yet processing.                               |
   +--------+----------------------------------------------------------+
   | '4'    | 'pending-held': The Job is not a candidate for           |
   |        | processing for any number of reasons but will return to  |
   |        | the 'pending' state as soon as the reasons are no longer |
   |        | present.  The Job's "job-state-reasons" attribute MUST   |
   |        | indicate why the Job is no longer a candidate for        |
   |        | processing.                                              |
   +--------+----------------------------------------------------------+
   | '5'    | 'processing': One or more of the following: (1) the Job  |
   |        | is using, or is attempting to use, one or more purely    |
   |        | software processes that are analyzing, creating, or      |
   |        | interpreting a PDL, etc.; (2) the Job is using, or is    |
   |        | attempting to use, one or more hardware devices that are |
   |        | interpreting a PDL; making marks on a medium; and/or     |
   |        | performing finishing, such as stapling, etc.; (3) the    |
   |        | Printer has made the Job ready for printing, but the     |
   |        | Output Device is not yet printing it, either because the |
   |        | Job hasn't reached the Output Device or because the Job  |
   |        | is queued in the Output Device or some other spooler,    |
   |        | waiting for the Output Device to print it.  When the Job |
   |        | is in the 'processing' state, the entire Job state       |
   |        | includes the detailed status represented in the          |
   |        | Printer's "printer-state", "printer-state-reasons", and  |
   |        | "printer-state-message" attributes.  Implementations MAY |
   |        | include additional values in the Job's "job-state-       |
   |        | reasons" attribute to indicate the progress of the Job,  |
   |        | such as adding the 'job-printing' value to indicate when |
   |        | the Output Device is actually making marks on paper      |
   |        | and/or the 'processing-to-stop-point' value to indicate  |
   |        | that the Printer is in the process of canceling or       |
   |        | aborting the Job.                                        |















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   +--------+----------------------------------------------------------+
   | '6'    | 'processing-stopped': The Job has stopped while          |
   |        | processing for any number of reasons and will return to  |
   |        | the 'processing' state as soon as the reasons are no     |
   |        | longer present.  The Job's "job-state-reasons" attribute |
   |        | MAY indicate why the Job has stopped processing.  For    |
   |        | example, if the Output Device is stopped, the 'printer-  |
   |        | stopped' value MAY be included in the Job's "job-state-  |
   |        | reasons" attribute.  Note: When an Output Device is      |
   |        | stopped, the device usually indicates its condition in   |
   |        | human-readable form locally at the device.  A Client can |
   |        | obtain more complete device status remotely by querying  |
   |        | the Printer's "printer-state", "printer-state-reasons",  |
   |        | and "printer-state-message" attributes.                  |
   +--------+----------------------------------------------------------+
   | '7'    | 'canceled':  The Job has been canceled by a Cancel-Job   |
   |        | operation, and the Printer has completed canceling the   |
   |        | Job.  All Job Status attributes have reached their final |
   |        | values for the Job.  While the Printer is canceling the  |
   |        | Job, the Job remains in its current state, but the Job's |
   |        | "job-state-reasons" attribute SHOULD contain the         |
   |        | 'processing-to-stop-point' value and one of the          |
   |        | 'canceled-by-user', 'canceled-by-operator', or           |
   |        | 'canceled-at-device' values.  When the Job moves to the  |
   |        | 'canceled' state, the 'processing-to-stop-point' value,  |
   |        | if present, MUST be removed, but 'canceled-by-xxx', if   |
   |        | present, MUST remain.                                    |
   +--------+----------------------------------------------------------+
   | '8'    | 'aborted': The Job has been aborted by the system,       |
   |        | usually while the Job was in the 'processing' or         |
   |        | 'processing-stopped' state, and the Printer has          |
   |        | completed aborting the Job; all Job Status attributes    |
   |        | have reached their final values for the Job.  While the  |
   |        | Printer is aborting the Job, the Job remains in its      |
   |        | current state, but the Job's "job-state-reasons"         |
   |        | attribute SHOULD contain the 'processing-to-stop-point'  |
   |        | and 'aborted-by-system' values.  When the Job moves to   |
   |        | the 'aborted' state, the 'processing-to-stop-point'      |
   |        | value, if present, MUST be removed, but the 'aborted-by- |
   |        | system' value, if present, MUST remain.                  |











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   +--------+----------------------------------------------------------+
   | '9'    | 'completed': The Job has completed successfully or with  |
   |        | warnings or errors after processing, all of the Job      |
   |        | Media Sheets have been successfully stacked in the       |
   |        | appropriate output bin(s), and all Job Status attributes |
   |        | have reached their final values for the Job.  The Job's  |
   |        | "job-state-reasons" attribute SHOULD contain one of the  |
   |        | 'completed-successfully', 'completed-with-warnings', or  |
   |        | 'completed-with-errors' values.                          |
   +--------+----------------------------------------------------------+

                     Table 15: "job-state" Enum Values

5.3.7.1.  Forwarding Servers

   As with all other IPP attributes, if the implementation cannot
   determine the correct value for this attribute, it SHOULD respond
   with the out-of-band 'unknown' value (see Section 5.1) rather than
   try to guess at some possibly incorrect value and confuse the
   End User about the state of the Job.  For example, if the
   implementation is just a gateway into some printing system from which
   it can normally get status, but temporarily is unable, then the
   implementation should return the 'unknown' value.  However, if the
   implementation is a gateway to a printing system that never provides
   detailed status about the Print Job, the implementation MAY set the
   IPP Job's state to 'completed', provided that it also sets the
   'queued-in-device' value in the Job's "job-state-reasons" attribute
   (see Section 5.3.8).

5.3.7.2.  Partitioning of Job States

   This section describes the partitioning of the seven Job states into
   phases: Job Not Completed, Job Retention, Job History, and Job
   Removal.  This section also explains the 'job-restartable' value of
   the "job-state-reasons" Job Status attribute for use with the
   Restart-Job and Resubmit-Job [PWG5100.11] operations.

   Job Not Completed: When a Job is in the 'pending', 'pending-held',
   'processing', or 'processing-stopped' state, the Job is not
   completed.

   Job Retention: When a Job enters one of the three terminal Job states
   -- 'completed', 'canceled', or 'aborted' -- the IPP Printer MAY
   "retain" the Job in a restartable condition for an implementation-
   defined time period.  This time period MAY be zero seconds and MAY
   depend on the terminal Job state.  This phase is called "Job
   Retention".  While in the Job Retention phase, the Job's Document
   data is retained and a Client can restart the Job using the



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   Restart-Job operation.  If the Printer supports the Restart-Job or
   Resubmit-Job operation, then it SHOULD indicate that the Job is
   restartable by adding the 'job-restartable' value to the Job's
   "job-state-reasons" attribute (see Section 5.3.8) during the Job
   Retention phase.

   Job History: After the Job Retention phase expires for a Job, the
   Printer deletes the Document data for the Job and the Job becomes
   part of the Job History.  The Printer MAY also delete any number of
   the Job attributes.  Since the Job is no longer restartable, the
   Printer MUST remove the 'job-restartable' value from the Job's
   "job-state-reasons" attribute, if present.  Printers SHOULD keep the
   Job in the Job History phase for at least 60 seconds to allow Clients
   to discover the final disposition of the Job.

   Job Removal: After the Job has remained in the Job History for an
   implementation-defined time, such as when the number of Jobs exceeds
   a fixed number or after a fixed time period (which MAY be
   zero seconds), the IPP Printer removes the Job from the system.

   Using the Get-Jobs operation and supplying the 'not-completed' value
   for the "which-jobs" operation attribute, a Client is requesting Jobs
   in the Job Not Completed phase.  Using the Get-Jobs operation and
   supplying the 'completed' value for the "which-jobs" operation
   attribute, a Client is requesting Jobs in the Job Retention and Job
   History phases.  Using the Get-Job-Attributes operation, a Client is
   requesting a Job in any phase except Job Removal.  After Job Removal,
   the Get-Job-Attributes and Get-Jobs operations no longer are capable
   of returning any information about a Job.

5.3.8.  job-state-reasons (1setOf type2 keyword)

   This REQUIRED attribute provides additional information about the
   Job's current state, i.e., information that augments the value of the
   Job's "job-state" attribute.

   These values MAY be used with any Job state or states for which the
   reason makes sense.  Some of these value definitions indicate
   conformance requirements; the rest are OPTIONAL.  Furthermore, when
   implemented, the Printer MUST return these values when the reason
   applies and MUST NOT return them when the reason no longer applies,
   whether the value of the Job's "job-state" attribute changed or not.
   When the Job does not have any reasons for being in its current
   state, the value of the Job's "job-state-reasons" attribute MUST be
   'none'.






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   Note: While values cannot be added to the "job-state" attribute
   without impacting deployed Clients that take actions upon receiving
   "job-state" values, it is the intent that additional
   "job-state-reasons" values can be defined and registered without
   impacting such deployed Clients.  In other words, the
   "job-state-reasons" attribute is intended to be extensible.

   The following standard 'keyword' values are defined.  For ease of
   understanding, the values are presented in the order in which the
   reasons are likely to occur (if implemented):

   o  'none': There are no reasons for the Job's current state.  This
      state reason is semantically equivalent to "job-state-reasons"
      without any value and MUST be used when there is no other value,
      since the '1setOf' attribute syntax requires at least one value.

   o  'job-incoming': Either (1) the Printer has accepted the Create-Job
      operation and is expecting additional Send-Document and/or
      Send-URI operations or (2) the Printer is retrieving/accepting
      Document data as a result of a Print-Job, Print-URI,
      Send-Document, or Send-URI operation.

   o  'job-data-insufficient': The Create-Job operation has been
      accepted by the Printer, but the Printer is expecting additional
      Document data before it can move the Job into the 'processing'
      state.  If a Printer starts processing before it has received all
      data, the Printer removes the 'job-data-insufficient' reason, but
      the 'job-incoming' reason remains.  If a Printer starts processing
      after it has received all data, the Printer removes the
      'job-data-insufficient' reason and the 'job-incoming' reason at
      the same time.

   o  'document-access-error': After accepting a Print-URI or Send-URI
      request, the Printer could not access one or more Documents passed
      by reference.  This reason is intended to cover any file access
      problem, including 'file does not exist' and 'access denied'
      because of an access control problem.  The Printer MAY also
      indicate the Document access error using the
      "job-document-access-errors" Job Status attribute (see
      Section 5.3.11).  The Printer can (1) abort the Job and move the
      Job to the 'aborted' Job state or (2) print all Documents that are
      accessible and move the Job to the 'completed' Job state with the
      'completed-with-errors' value in the Job's "job-state-reasons"
      attribute.  This value SHOULD be supported if the Print-URI or
      Send-URI operations are supported.






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   o  'submission-interrupted': The Job was not completely submitted for
      some unforeseen reason, such as (1) the Printer has crashed before
      the Job was closed by the Client, (2) the Printer or the Document
      transfer method has crashed in some non-recoverable way before the
      Document data was entirely transferred to the Printer, or (3) the
      Client crashed or failed to close the Job before the time-out
      period.  See Section 5.4.31.

   o  'job-outgoing': The Printer is transmitting the Job to the Output
      Device.

   o  'job-hold-until-specified': The value of the Job's
      "job-hold-until" attribute was specified with a time period that
      is still in the future.  The Job MUST NOT be a candidate for
      processing until this reason is removed and there are no other
      reasons to hold the Job.  This value SHOULD be supported if the
      "job-hold-until" Job Template attribute is supported.

   o  'resources-are-not-ready': At least one of the resources needed by
      the Job, such as media, fonts, resource objects, etc., is not
      ready on any of the physical Output Devices for which the Job is a
      candidate.  This condition MAY be detected when the Job is
      accepted, or subsequently while the Job is pending or processing,
      depending on implementation.  The Job can remain in its current
      state or be moved to the 'pending-held' state, depending on
      implementation and/or Job scheduling policy.

   o  'printer-stopped-partly': The value of the Printer's
      "printer-state-reasons" attribute contains the value
      'stopped-partly'.

   o  'printer-stopped': The value of the Printer's "printer-state"
      attribute is 'stopped'.

   o  'job-interpreting': The Job is in the 'processing' state, but,
      more specifically, the Printer is interpreting the Document data.

   o  'job-queued': The Job is in the 'processing' state, but, more
      specifically, the Printer has queued the Document data.

   o  'job-transforming': The Job is in the 'processing' state, but,
      more specifically, the Printer is interpreting Document data and
      producing another electronic representation.

   o  'job-queued-for-marker': The Job is in any of the 'pending-held',
      'pending', or 'processing' states, but, more specifically, the
      Printer has completed enough processing of the Document to be able
      to start marking, and the Job is waiting for the marker.  Systems



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      that require human intervention to release Jobs using the
      Release-Job operation put the Job into the 'pending-held' Job
      state.  Systems that automatically select a Job to use the marker
      put the Job into the 'pending' Job state or keep the Job in the
      'processing' Job state while waiting for the marker, depending on
      implementation.  All implementations put the Job into the
      'processing' state when marking does begin.

   o  'job-printing': The Output Device is marking media.  This value is
      useful for Printers that spend a great deal of time processing
      (1) when no marking is happening and they want to show that
      marking is now happening or (2) when the Job is in the process of
      being canceled or aborted while the Job remains in the
      'processing' state, but the marking has not yet stopped so that
      Impression or sheet counts are still increasing for the Job.

   o  'job-canceled-by-user': The Job was canceled by the owner of the
      Job using the Cancel-Job request, i.e., by a user whose
      authenticated identity is the same as the value of the originating
      user that created the Job, or by some other authorized End User,
      such as a member of the Job owner's security group.  This value
      SHOULD be supported.

   o  'job-canceled-by-operator': The Job was canceled by the Operator
      using the Cancel-Job request, i.e., by a user who has been
      authenticated as having Operator privileges (whether local or
      remote).  If the security policy is to allow anyone to cancel
      anyone's Job, then this value can be used when the Job is canceled
      by other than the owner of the Job.  For such a security policy,
      in effect, everyone is an Operator as far as canceling Jobs with
      IPP is concerned.  This value SHOULD be supported if the
      implementation permits canceling by other than the owner of
      the Job.

   o  'job-canceled-at-device': The Job was canceled by an unidentified
      local user, i.e., a user at a console at the device.  This value
      SHOULD be supported if the implementation supports canceling Jobs
      at the console.

   o  'aborted-by-system': The Job (1) is in the process of being
      aborted, (2) has been aborted by the system and placed in the
      'aborted' state, or (3) has been aborted by the system and placed
      in the 'pending-held' state, so that a user or Operator can
      manually try the Job again.  This value SHOULD be supported.







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   o  'unsupported-compression': The Job was aborted by the system
      because the Printer determined, while attempting to decompress the
      Document data, that the compression algorithm is actually not
      among those supported by the Printer.  This value MUST be
      supported, since "compression" is a REQUIRED operation attribute.

   o  'compression-error': The Job was aborted by the system because the
      Printer encountered an error in the Document data while
      decompressing it.  If the Printer posts this reason, the Document
      data has already passed any tests that would have led to the
      'unsupported-compression' "job-state-reasons" value.

   o  'unsupported-document-format': The Job was aborted by the system
      because the Document data's "document-format" attribute is not
      among those supported by the Printer.  If the Client specifies
      "document-format" as 'application/octet-stream', the Printer MAY
      abort the Job and post this reason even though the
      "document-format" value is among the values of the Printer's
      "document-format-supported" Printer attribute but not among the
      auto-sensed Document formats.  This value MUST be supported, since
      "document-format" is a REQUIRED operation attribute.

   o  'document-format-error': The Job was aborted by the system because
      the Printer encountered an error in the Document data while
      processing it.  If the Printer posts this reason, the Document
      data has already passed any tests that would have led to the
      'unsupported-document-format' "job-state-reasons" value.

   o  'processing-to-stop-point': The requester has issued a Cancel-Job
      operation or the Printer has aborted the Job, but the Printer is
      still performing some actions on the Job until a specified stop
      point occurs or Job termination/cleanup is completed.

      If the implementation requires some measurable time to cancel the
      Job in the 'processing' or 'processing-stopped' Job state, the
      Printer MUST use this value to indicate that the Printer is still
      performing some actions on the Job while the Job remains in the
      'processing' or 'processing-stopped' state.  Once at the stop
      point, the Printer moves the Job from the 'processing' state to
      the 'canceled' or 'aborted' Job state.

   o  'service-off-line': The Printer is offline and accepting no Jobs.
      All 'pending' Jobs are put into the 'pending-held' state.  This
      situation could be true if the service's or Document transform's
      input is impaired or broken.

   o  'job-completed-successfully': The Job completed successfully.
      This value SHOULD be supported.



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   o  'job-completed-with-warnings': The Job completed with warnings.
      This value SHOULD be supported if the implementation detects
      warnings.

   o  'job-completed-with-errors': The Job completed with errors (and
      possibly warnings too).  This value SHOULD be supported if the
      implementation detects errors.

   o  'job-restartable': This Job is retained (see Section 5.3.7.2) and
      is currently able to be restarted using the Restart-Job (see
      Section 4.3.7) or Resubmit-Job [PWG5100.11] operation.  If
      'job-restartable' is a value of the Job's "job-state-reasons"
      attribute, then the Printer MUST accept a Restart-Job operation
      for that Job.  This value SHOULD be supported if the Restart-Job
      operation is supported.

   o  'queued-in-device': The Job has been forwarded to a device or
      print system that is unable to send back status.  The Printer sets
      the Job's "job-state" attribute to 'completed' and adds the
      'queued-in-device' value to the Job's "job-state-reasons"
      attribute to indicate that the Printer has no additional
      information about the Job and never will have any better
      information.  See Section 5.3.7.1.

5.3.9.  job-state-message (text(MAX))

   This RECOMMENDED attribute specifies information about the
   "job-state" and "job-state-reasons" attributes in human-readable
   text.  If the Printer supports this attribute, the Printer MUST be
   able to generate this message in any of the natural languages
   identified by the Printer's "generated-natural-language-supported"
   attribute (see the "attributes-natural-language" operation attribute
   specified in Section 4.1.4.1).

   The value SHOULD NOT contain additional information not contained in
   the values of the "job-state" and "job-state-reasons" attributes,
   such as interpreter error information.  Otherwise, application
   programs might attempt to parse the (localized) text.  For such
   additional information, such as interpreter errors for application
   program consumption or specific Document access errors, new
   attributes with 'keyword' values need to be developed and registered.










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5.3.10.  job-detailed-status-messages (1setOf text(MAX))

   This attribute specifies additional detailed and technical
   information about the Job.  The Printer SHOULD localize the message,
   unless such localization would obscure the technical meaning of the
   message.  Clients MUST NOT attempt to parse the value of this
   attribute.  See "job-document-access-errors" (Section 5.3.11) for
   additional errors that a program can process.

5.3.11.  job-document-access-errors (1setOf text(MAX))

   This attribute provides additional information about each Document
   access error for this Job encountered by the Printer after it
   returned a response to the Print-URI or Send-URI operation and
   subsequently attempted to access document(s) supplied in the
   Print-URI or Send-URI operation.  For errors in the protocol that is
   identified by the URI scheme in the "document-uri" operation
   attribute, such as 'http:' or 'ftp:', the error code is returned in
   parentheses, followed by the URI.  For example:

   (404) http://www.example.com/filename.pdf

   Most Internet protocols use decimal error codes (unlike IPP), so the
   ASCII error code representation is in decimal.

5.3.12.  number-of-documents (integer(0:MAX))

   This attribute indicates the number of Documents in the Job, i.e.,
   the number of Send-Document, Send-URI, Print-Job, or Print-URI
   operations that the Printer has accepted for this Job, regardless of
   whether the Document data has reached the Printer.

   Implementations supporting the RECOMMENDED Create-Job/Send-Document/
   Send-URI operations SHOULD support this attribute so that Clients can
   query the number of Documents in each Job.

5.3.13.  output-device-assigned (name(127))

   This attribute identifies the Output Device to which the Printer has
   assigned this Job.  If an Output Device implements an embedded
   Printer, the Printer SHOULD set this attribute.  If a print server
   implements a Printer, the value MAY be empty (zero-length string) or
   not returned until the Printer assigns an Output Device to the Job.
   This attribute is particularly useful when a single Printer supports
   multiple devices (so-called "fan-out" -- see Section 3.1).






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5.3.14.  Event Time Job Status Attributes

   This section defines the Job Status attributes that indicate the time
   at which certain events occur for a Job.  If the Job event has not
   yet occurred, then the Printer MUST return the 'no-value' out-of-band
   value (see the beginning of Section 5.1).  The
   "time-at-xxx (integer)" attributes represent time as an 'integer'
   representing the number of seconds since the device was powered up
   (informally called "time ticks").  The "date-time-at-xxx (dateTime)"
   attributes represent time as 'dateTime' representing date and time
   (including an offset from UTC).

   In order to populate these attributes, the Printer copies the
   value(s) of the following Printer Status attributes at the time the
   event occurs:

   1.  the value in the Printer's "printer-up-time" attribute for the
       "time-at-xxx (integer)" attributes.

   2.  the value in the Printer's "printer-current-time" attribute for
       the "date-time-at-xxx (dateTime)" attributes.

   If the Printer resets its "printer-up-time" attribute to 1 on
   power-up (see Section 5.4.29) and has persistent Jobs, then it MUST
   change all of those Jobs' "time-at-xxx (integer)" (time tick) Job
   attributes whose events have occurred either to:

   1.  0 to indicate that the event happened before the most recent
       power-up, or

   2.  the negative of the number of seconds before the most recent
       power-up that the event took place, if the Printer knows the
       exact number of seconds.

   If a Client queries a "time-at-xxx (integer)" time tick Job attribute
   and finds the value to be 0 or negative, the Client MUST assume that
   the event occurred in some life other than the Printer's current
   life.

   Note: A Printer does not change the values of any
   "date-time-at-xxx (dateTime)" Job attributes on power-up.

5.3.14.1.  time-at-creation (integer(MIN:MAX))

   This REQUIRED attribute indicates the time at which the Job was
   created.





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5.3.14.2.  time-at-processing (integer(MIN:MAX))

   This REQUIRED attribute indicates the time at which the Job first
   began processing after the Job Creation request or the most recent
   Restart-Job operation.  The out-of-band 'no-value' value is returned
   if the Job has not yet been in the 'processing' state (see the
   beginning of Section 5.1).

5.3.14.3.  time-at-completed (integer(MIN:MAX))

   This REQUIRED attribute indicates the time at which the Job entered a
   Terminating State ('completed', 'canceled', or 'aborted').  The
   out-of-band 'no-value' value is returned if the Job has not yet
   completed, been canceled, or aborted (see the beginning of
   Section 5.1).

5.3.14.4.  job-printer-up-time (integer(1:MAX))

   This REQUIRED Job Status attribute indicates the amount of time (in
   seconds) that the Printer implementation has been up and running.
   This attribute is an alias for the "printer-up-time" Printer Status
   attribute (see Section 5.4.29).

   A Client MAY request this attribute in a Get-Job-Attributes or
   Get-Jobs request and use the value returned in combination with other
   requested Event Time Job Status attributes in order to display time
   attributes to a user.  The difference between this attribute and the
   'integer' value of a "time-at-xxx" attribute is the number of seconds
   ago that the "time-at-xxx" event occurred.  A Client can compute the
   wall-clock time at which the "time-at-xxx" event occurred by
   subtracting this difference from the Client's wall-clock time.

5.3.14.5.  date-time-at-creation (dateTime|unknown)

   This RECOMMENDED attribute indicates the date and time at which the
   Job was created.

5.3.14.6.  date-time-at-processing (dateTime|unknown|no-value)

   This RECOMMENDED attribute indicates the date and time at which the
   Job first began processing after the Job Creation request or the most
   recent Restart-Job operation.

5.3.14.7.  date-time-at-completed (dateTime|unknown|no-value)

   This RECOMMENDED attribute indicates the date and time at which the
   Job entered a Terminating State ('completed', 'canceled', or
   'aborted').



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5.3.15.  number-of-intervening-jobs (integer(0:MAX))

   This attribute indicates the number of Jobs that are "ahead" of this
   Job in the relative chronological order of expected time to complete
   (i.e., the current scheduled order).  For efficiency, it is only
   necessary to calculate this value when an operation is performed that
   requests this attribute.

5.3.16.  job-message-from-operator (text(127))

   This attribute provides a message from an Operator, Administrator, or
   "intelligent" process to indicate to the End User the reasons for
   modification or other management action taken on a Job.

5.3.17.  Job Size Attributes

   This subsection defines Job attributes that describe the size of the
   Job.  These attributes are not intended to be counters; they are
   intended to be useful routing and scheduling information if known.
   For these attributes, the Printer can try to compute the value if it
   is not supplied in the Job Creation request.  Even if the Client does
   supply a value for these three attributes in the Job Creation
   request, the Printer MAY choose to change the value if the Printer is
   able to compute a value that is more accurate than the
   Client-supplied value.  The Printer can determine the correct value
   for these attributes either right at Job submission time or at any
   later point in time.

5.3.17.1.  job-k-octets (integer(0:MAX))

   This attribute specifies the total size of the Document(s) in
   K octets, i.e., in units of 1024 octets requested to be processed
   in the Job.  The value MUST be rounded up, so that a Job between
   1 and 1024 octets MUST be indicated as being 1, 1025 to 2048 MUST
   be 2, etc.

   This value MUST NOT include the multiplicative factors contributed by
   the number of copies specified by the "copies" attribute, independent
   of whether the device can process multiple copies without making
   multiple passes over the Job or Document data and independent of
   whether the output is collated or not.  Thus, the value is
   independent of the implementation and indicates the size of the
   Document(s) measured in K octets independent of the number of copies.








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   This value also MUST NOT include the multiplicative factor due to a
   copies instruction embedded in the Document data.  If the Document
   data actually includes replications of the Document data, this value
   will include such replication.  In other words, this value is always
   the size of the source Document data, rather than a measure of the
   hardcopy output to be produced.

5.3.17.2.  job-impressions (integer(0:MAX))

   This RECOMMENDED attribute specifies the total size in number of
   Impressions of the Document(s) being submitted (see the definition of
   "Impression" in Section 2.3.4).

   As with "job-k-octets", this value MUST NOT include the
   multiplicative factors contributed by the number of copies specified
   by the "copies" attribute, independent of whether the device can
   process multiple copies without making multiple passes over the Job
   or Document data and independent of whether the output is collated or
   not.  Thus, the value is independent of the implementation and
   reflects the size of the Document(s) measured in Impressions
   independent of the number of copies.

   As with "job-k-octets", this value also MUST NOT include the
   multiplicative factor due to a copies instruction embedded in the
   Document data.  If the Document data actually includes replications
   of the Document data, this value will include such replication.  In
   other words, this value is always the number of Impressions in the
   source Document data, rather than a measure of the number of
   Impressions to be produced by the Job.

5.3.17.3.  job-media-sheets (integer(1:MAX))

   This RECOMMENDED attribute specifies the total number of Media Sheets
   to be produced for this Job.

   Unlike the "job-k-octets" and the "job-impressions" attributes, this
   value MUST include the multiplicative factors contributed by the
   number of copies specified by the "copies" attribute and a 'number of
   copies' instruction embedded in the Document data, if any.  This
   difference allows the Administrator to control the lower and upper
   bounds of both (1) the size of the Document(s) with
   "job-k-octets-supported" and "job-impressions-supported" and
   (2) the size of the Job with "job-media-sheets-supported".








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5.3.18.  Job Progress Attributes

   This subsection defines Job attributes that describe the progress of
   the Job.  These attributes are intended to be counters.  That is, the
   values for a Job that has not started processing MUST be 0.  When the
   Job's "job-state" is 'processing' or 'processing-stopped', this value
   is intended to contain the amount of the Job that has been processed
   to the time at which the attributes are requested.  When the Job
   enters the 'completed', 'canceled', or 'aborted' states, these values
   are the final values for the Job.

5.3.18.1.  job-k-octets-processed (integer(0:MAX))

   This attribute specifies the total number of octets processed in
   K octets, i.e., in units of 1024 octets so far.  The value MUST be
   rounded up, so that a Job between 1 and 1024 octets inclusive MUST be
   indicated as being 1, 1025 to 2048 inclusive MUST be 2, etc.

   For implementations where multiple copies are produced by the
   interpreter with only a single pass over the data, the final value
   MUST be equal to the value of the "job-k-octets" attribute.  For
   implementations where multiple copies are produced by the interpreter
   by processing the data for each copy, the final value MUST be a
   multiple of the value of the "job-k-octets" attribute.

5.3.18.2.  job-impressions-completed (integer(0:MAX))

   This RECOMMENDED attribute specifies the number of Impressions
   completed for the Job so far.  For printing devices, the Impressions
   completed includes interpreting, marking, and stacking the output.

5.3.18.3.  job-media-sheets-completed (integer(0:MAX))

   This RECOMMENDED Job attribute specifies the number of Media Sheets
   that have been marked and stacked for the entire Job so far, whether
   those sheets have been processed on one side or on both.

5.3.19.  attributes-charset (charset)

   This REQUIRED attribute is populated using the value in the
   Client-supplied "attributes-charset" attribute in the Job Creation
   request.  It identifies the charset (coded character set and encoding
   method) used by any Job attributes with attribute syntaxes 'text' and
   'name' that were supplied by the Client in the Job Creation request.
   See Section 4.1.4 for a complete description of the
   "attributes-charset" operation attribute.





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   This attribute does not indicate the charset in which the 'text' and
   'name' values are stored internally in the Job.  The internal charset
   is implementation defined.  The Printer MUST convert from whatever
   the internal charset is to that being requested in an operation as
   specified in Section 4.1.4.

5.3.20.  attributes-natural-language (naturalLanguage)

   This REQUIRED attribute is populated using the value in the
   Client-supplied "attributes-natural-language" attribute in the Job
   Creation request.  It identifies the natural language used for any
   Job attributes with attribute syntaxes 'text' and 'name' that were
   supplied by the Client in the Job Creation request.  See
   Section 4.1.4 for a complete description of the
   "attributes-natural-language" operation attribute.  See
   Sections 5.1.2.2 and 5.1.3.2 for how a Natural Language Override can
   be supplied explicitly for each 'text' and 'name' attribute value
   that differs from the value identified by the
   "attributes-natural-language" attribute.

5.4.  Printer Description and Status Attributes

   These attributes form the attribute group called
   "printer-description".  Tables 16 and 17 summarize these attributes,
   their syntax, and whether they are REQUIRED for a Printer to support.
   If they are not indicated as REQUIRED, they are OPTIONAL.  The
   maximum size in octets for 'text' and 'name' attributes is indicated
   in parentheses.

   Note: How these attributes are set by an Administrator is outside the
   scope of this document.

   +-----------------------------+-----------------------+-------------+
   | Attribute                   | Syntax                | REQUIRED?   |
   +-----------------------------+-----------------------+-------------+
   | charset-configured          | charset               | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | charset-supported           | 1setOf charset        | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | color-supported             | boolean               | RECOMMENDED |
   +-----------------------------+-----------------------+-------------+
   | compression-supported       | 1setOf type2 keyword  | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | document-format-default     | mimeMediaType         | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | document-format-supported   | 1setOf mimeMediaType  | REQUIRED    |





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   +-----------------------------+-----------------------+-------------+
   | generated-natural-language- | 1setOf                | REQUIRED    |
   | supported                   | naturalLanguage       |             |
   +-----------------------------+-----------------------+-------------+
   | ipp-versions-supported      | 1setOf type2 keyword  | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | job-impressions-supported   | rangeOfInteger(0:MAX) | RECOMMENDED |
   +-----------------------------+-----------------------+-------------+
   | job-k-octets-supported      | rangeOfInteger(0:MAX) |             |
   +-----------------------------+-----------------------+-------------+
   | job-media-sheets-supported  | rangeOfInteger(1:MAX) |             |
   +-----------------------------+-----------------------+-------------+
   | multiple-document-jobs-     | boolean               | RECOMMENDED |
   | supported                   |                       |             |
   +-----------------------------+-----------------------+-------------+
   | multiple-operation-time-out | integer(1:MAX)        | RECOMMENDED |
   +-----------------------------+-----------------------+-------------+
   | natural-language-configured | naturalLanguage       | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | operations-supported        | 1setOf type2 enum     | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | pdl-override-supported      | type2 keyword         | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | printer-driver-installer    | uri                   |             |
   +-----------------------------+-----------------------+-------------+
   | printer-info                | text(127)             | RECOMMENDED |
   +-----------------------------+-----------------------+-------------+
   | printer-location            | text(127)             | RECOMMENDED |
   +-----------------------------+-----------------------+-------------+
   | printer-make-and-model      | text(127)             | RECOMMENDED |
   +-----------------------------+-----------------------+-------------+
   | printer-message-from-       | text(127)             |             |
   | operator                    |                       |             |
   +-----------------------------+-----------------------+-------------+
   | printer-more-info-          | uri                   |             |
   | manufacturer                |                       |             |
   +-----------------------------+-----------------------+-------------+
   | printer-name                | name(127)             | REQUIRED    |
   +-----------------------------+-----------------------+-------------+
   | reference-uri-schemes-      | 1setOf uriScheme      |             |
   | supported                   |                       |             |
   +-----------------------------+-----------------------+-------------+

           Table 16: Printer Description Attributes (READ-WRITE)







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   +------------------------------+----------------------+-------------+
   | Attribute                    | Syntax               | REQUIRED?   |
   +------------------------------+----------------------+-------------+
   | pages-per-minute-color       | integer(0:MAX)       | RECOMMENDED |
   +------------------------------+----------------------+-------------+
   | pages-per-minute             | integer(0:MAX)       | RECOMMENDED |
   +------------------------------+----------------------+-------------+
   | printer-current-time         | dateTime|unknown     | RECOMMENDED |
   +------------------------------+----------------------+-------------+
   | printer-is-accepting-jobs    | boolean              | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | printer-more-info            | uri                  | RECOMMENDED |
   +------------------------------+----------------------+-------------+
   | printer-state                | type1 enum           | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | printer-state-message        | text(MAX)            | RECOMMENDED |
   +------------------------------+----------------------+-------------+
   | printer-state-reasons        | 1setOf type2 keyword | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | printer-up-time              | integer(1:MAX)       | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | printer-uri-supported        | 1setOf uri           | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | queued-job-count             | integer(0:MAX)       | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | uri-authentication-supported | 1setOf type2 keyword | REQUIRED    |
   +------------------------------+----------------------+-------------+
   | uri-security-supported       | 1setOf type2 keyword | REQUIRED    |
   +------------------------------+----------------------+-------------+

              Table 17: Printer Status Attributes (READ-ONLY)

5.4.1.  printer-uri-supported (1setOf uri)

   This REQUIRED Printer attribute contains one or more URIs for the
   Printer.  It MAY contain more than one URI for the Printer.  An
   Administrator determines a Printer's URIs and configures this
   attribute to contain those URIs by some means outside the scope of
   this IPP/1.1 document.  The precise format of the URIs is
   implementation dependent and depends on the protocol.  See
   Sections 5.4.2 and 5.4.3 for a description of the
   "uri-authentication-supported" and "uri-security-supported"
   attributes, both of which are the REQUIRED companion attributes to
   this "printer-uri-supported" attribute.  See Sections 3.4 ("Object
   Identity") and 9.2 ("URIs in Operation, Job, and Printer Attributes")
   for more information.





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5.4.2.  uri-authentication-supported (1setOf type2 keyword)

   This REQUIRED Printer attribute MUST have the same cardinality
   (contain the same number of values) as the "printer-uri-supported"
   attribute.  This attribute identifies the Client Authentication
   mechanism associated with each URI listed in the
   "printer-uri-supported" attribute.  The Printer uses the specified
   mechanism to identify the authenticated user (see Section 9.3).  The
   "i-th" value in "uri-authentication-supported" corresponds to the
   "i-th" value in "printer-uri-supported", and it describes the
   authentication mechanisms used by the Printer when accessed via that
   URI.  See [RFC8010] for more details on Client Authentication.

   The following standard 'keyword' values are defined:

   o  'none': There is no authentication mechanism associated with the
      URI.  The Printer assumes that the authenticated user is
      'anonymous'.

   o  'requesting-user-name': When a Client performs an operation whose
      target is the associated URI, the Printer assumes that the
      authenticated user is specified by the "requesting-user-name"
      operation attribute (see Section 9.3).  If the
      "requesting-user-name" attribute is absent in a request, the
      Printer assumes that the authenticated user is 'anonymous'.

   o  'basic': When a Client performs an operation whose target is the
      associated URI, the Printer challenges the Client with HTTP Basic
      authentication [RFC7617].  The Printer assumes that the
      authenticated user is the name received via the Basic
      authentication mechanism.

   o  'digest': When a Client performs an operation whose target is the
      associated URI, the Printer challenges the Client with HTTP Digest
      authentication [RFC7616].  The Printer assumes that the
      authenticated user is the name received via the Digest
      authentication mechanism.

   o  'certificate': When a Client performs an operation whose target is
      the associated URI, the Printer expects the Client to provide an
      X.509 certificate.  The Printer assumes that the authenticated
      user is one of the textual names (Common Name or Subject Alternate
      Names) contained within the certificate.








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5.4.3.  uri-security-supported (1setOf type2 keyword)

   This REQUIRED Printer attribute MUST have the same cardinality
   (contain the same number of values) as the "printer-uri-supported"
   attribute.  This attribute identifies the security mechanisms used
   for each URI listed in the "printer-uri-supported" attribute.  The
   "i-th" value in "uri-security-supported" corresponds to the "i-th"
   value in "printer-uri-supported", and it describes the security
   mechanisms used for accessing the Printer via that URI.  See
   [RFC8010] for more details on security mechanisms.

   The following standard 'keyword' values are defined:

   o  'none': There are no secure communication channel protocols in use
      for the given URI.

   o  'tls': TLS [RFC5246] [RFC7525] is the secure communications
      channel protocol in use for the given URI.

   This attribute is orthogonal to the definition of a Client
   Authentication mechanism.  Specifically, 'none' does not exclude
   Client Authentication.  See Section 5.4.2.

   Consider the following example.  For a single Printer, an
   Administrator configures the "printer-uri-supported",
   "uri-authentication-supported", and "uri-security-supported"
   attributes as follows:

      "printer-uri-supported": 'ipp://printer.example.com/ipp/print/
      open-use-printer', 'ipp://printer.example.com/ipp/print/
      restricted-use-printer', 'ipps://printer.example.com/ipp/print/
      private-printer'

      "uri-authentication-supported": 'none', 'digest', 'basic'

      "uri-security-supported": 'none', 'none', 'tls'

   In this case, one Printer has three URIs.

   o  For the first URI, 'ipp://printer.example.com/ipp/print/
      open-use-printer', the value 'none' in "uri-security-supported"
      indicates that there is no secure channel protocol configured to
      run under HTTP.  The value of 'none' in
      "uri-authentication-supported" indicates that all users are
      'anonymous'.  There will be no challenge, and the Printer will
      ignore "requesting-user-name".





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   o  For the second URI, 'ipp://printer.example.com/ipp/print/
      restricted-use-printer', the value 'none' in
      "uri-security-supported" indicates that there is no secure channel
      protocol configured to run under HTTP.  The value of 'digest' in
      "uri-authentication-supported" indicates that the Printer will
      issue a challenge and that the Printer will use the name supplied
      by the Digest mechanism to determine the authenticated user (see
      Section 9.3).

   o  For the third URI, 'ipps://printer.example.com/ipp/print/
      private-printer', the value 'tls' in "uri-security-supported"
      indicates that TLS is being used to secure the channel.  The
      Client SHOULD be prepared to use TLS framing to negotiate an
      acceptable ciphersuite to use while communicating with the
      Printer.  In this case, the name implies the use of a secure
      communications channel, but the fact is made explicit by the
      presence of the 'tls' value in "uri-security-supported".  The
      Client does not need to resort to understanding which security
      mechanisms it must use by following naming conventions or by
      parsing the URI to determine which security mechanisms are
      implied.  The value of 'basic' in "uri-authentication-supported"
      indicates that the Printer will issue a challenge and that the
      Printer will use the name supplied by the Basic mechanism to
      determine the authenticated user (see Section 9.3).  Because this
      challenge occurs in a TLS session, the channel is secure.

   Some Printers will be configured to support only one channel (either
   configured to use TLS access or not) and only one authentication
   mechanism.  Such Printers only have one URI listed in the
   "printer-uri-supported" attribute.  No matter the configuration of
   the Printer (whether it has only one URI or more than one URI), a
   Client MUST supply only one URI in the target "printer-uri" operation
   attribute.

5.4.4.  printer-name (name(127))

   This REQUIRED Printer attribute contains the name of the Printer.  It
   is a name that is more End User friendly than a URI.  An
   Administrator determines a Printer's name and sets this attribute to
   that name.  This name can be the last part of the Printer's URI, or
   it can be unrelated.  In non-US-English locales, a name can contain
   characters that are not allowed in a URI.

5.4.5.  printer-location (text(127))

   This RECOMMENDED Printer attribute identifies the location of the
   device.  This could include things like 'in Room 123A, second floor
   of building XYZ'.



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5.4.6.  printer-info (text(127))

   This RECOMMENDED Printer attribute provides descriptive information
   about this Printer.  This could include things like 'This printer can
   be used for printing color transparencies for HR presentations', or
   'Out of courtesy for others, please print only small (1-5 page) jobs
   at this printer', or even 'This printer is going away on July 1;
   please find a new printer'.

5.4.7.  printer-more-info (uri)

   This RECOMMENDED Printer attribute contains a URI used to obtain more
   information about this specific Printer.  For example, this could be
   an HTTP URI referencing an HTML page accessible to a web browser.
   The information obtained from this URI is intended for End User
   consumption.  Features outside the scope of IPP can be accessed from
   this URI.  The information is intended to be specific to this Printer
   instance and site-specific services, e.g., Job pricing, services
   offered, and End User assistance.  The device manufacturer can
   initially populate this attribute.

5.4.8.  printer-driver-installer (uri)

   This Printer attribute contains a URI to use to locate the driver
   installer for this Printer.  This attribute is intended for
   consumption by automata.  The mechanics of Printer driver
   installation are outside the scope of this document.  The device
   manufacturer can initially populate this attribute.

5.4.9.  printer-make-and-model (text(127))

   This RECOMMENDED Printer attribute identifies the make and model of
   the device.  The device manufacturer can initially populate this
   attribute.

5.4.10.  printer-more-info-manufacturer (uri)

   This Printer attribute contains a URI used to obtain more information
   about this type of device.  The information obtained from this URI is
   intended for End User consumption.  Features outside the scope of IPP
   can be accessed from this URI (e.g., latest firmware, upgrades,
   Printer drivers, optional features available, details on color
   support).  The information is intended to be germane to this Printer
   without regard to site-specific modifications or services.  The
   device manufacturer can initially populate this attribute.






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5.4.11.  printer-state (type1 enum)

   This REQUIRED Printer attribute identifies the current state of the
   device.  The "printer-state reasons" attribute augments the
   "printer-state" attribute to give more detailed information about the
   Printer in the given Printer state.

   A Printer updates this attribute continually if asynchronous event
   notification [RFC3995] is supported.

   Standard enum values are defined in Table 18.  Values of
   "printer-state-reasons", such as 'spool-area-full' and
   'stopped-partly', MAY be used to provide further information.

   +-------+-----------------------------------------------------------+
   | Value | Symbolic Name and Description                             |
   +-------+-----------------------------------------------------------+
   | '3'   | 'idle': Indicates that new Jobs can start processing      |
   |       | without waiting.                                          |
   +-------+-----------------------------------------------------------+
   | '4'   | 'processing': Indicates that Jobs are processing; new     |
   |       | Jobs will wait before processing.                         |
   +-------+-----------------------------------------------------------+
   | '5'   | 'stopped': Indicates that no Jobs can be processed and    |
   |       | intervention is required.                                 |
   +-------+-----------------------------------------------------------+

                   Table 18: "printer-state" Enum Values

5.4.12.  printer-state-reasons (1setOf type2 keyword)

   This REQUIRED Printer attribute supplies additional detail about the
   device's state.  Some of the value definitions indicate conformance
   requirements; the rest are OPTIONAL.

   Each 'keyword' value MAY have a suffix to indicate its level of
   severity.  The three levels are 'report' (least severe), 'warning',
   and 'error' (most severe):

   o  '-report': This suffix indicates that the reason is a "report".
      An implementation can choose to omit some or all reports.  Some
      reports specify finer granularity about the Printer state; others
      serve as a precursor to a warning.  A report MUST contain nothing
      that could affect the printed output.  Reports correspond to the
      'other' value for the prtAlertSeverityLevel property in the
      Printer MIB [RFC3805].





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   o  '-warning': This suffix indicates that the reason is a "warning".
      An implementation can choose to omit some or all warnings.
      Warnings serve as a precursor to an error.  A warning MUST contain
      nothing that prevents a Job from completing, though in some cases
      the output can be of lower quality.  Warnings correspond to the
      'warning' value for the prtAlertSeverityLevel property in the
      Printer MIB [RFC3805].

   o  '-error': This suffix indicates that the reason is an "error".  An
      implementation MUST include all errors.  If this attribute
      contains one or more errors, the Printer MUST be in the 'stopped'
      state.  Errors correspond to the 'critical' value for the
      prtAlertSeverityLevel property in the Printer MIB [RFC3805].

   If the implementation does not add any one of the three suffixes and
   the value is not 'none', Clients can assume that the reason is an
   "error" if the Printer is in the 'stopped' state and a "warning" if
   the Printer is in any other state.

   If a Printer controls more than one Output Device, each value of this
   attribute MAY apply to one or more of the Output Devices.  An error
   on one Output Device that does not stop the Printer as a whole MAY
   appear as a warning in the Printer's "printer-state-reasons"
   attribute.  If "printer-state" for such a Printer has a value of
   'stopped', then there MUST be an error reason among the values in the
   "printer-state-reasons" attribute.

   The following standard 'keyword' values are defined:

   o  'none': There are no reasons.  This state reason is semantically
      equivalent to "printer-state-reasons" without any value and MUST
      be used, since the '1setOf' attribute syntax requires at least one
      value.

   o  'other': The device has detected a condition other than one listed
      in this document.

   o  'connecting-to-device': The Printer has scheduled a Job on the
      Output Device and is in the process of connecting to a shared
      network Output Device (and might not be able to actually start
      printing the Job for an arbitrarily long time, depending on the
      usage of the Output Device by other servers on the network).

   o  'cover-open': One or more covers on the device are open,
      equivalent to a prtCoverStatus [RFC3805] of 3 (coverOpen).

   o  'developer-empty: The device is out of developer.




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   o  'developer-low': The device is low on developer.

   o  'door-open': One or more doors on the device are open, equivalent
      to a prtCoverStatus [RFC3805] of 3 (coverOpen).

   o  'fuser-over-temp': The fuser temperature is above normal,
      equivalent to a prtMarkerStatus [RFC3805] of 19 (the sum of
      "Unavailable because Broken" (3) and "Critical Alerts" (16)).

   o  'fuser-under-temp': The fuser temperature is below normal,
      equivalent to a prtMarkerStatus [RFC3805] of 19 (the sum of
      "Unavailable because Broken" (3) and "Critical Alerts" (16)).

   o  'input-tray-missing': One or more input trays are not in the
      device, equivalent to a prtInputStatus [RFC3805] of 19 (the sum of
      "Unavailable because Broken" (3) and "Critical Alerts" (16)).

   o  'interlock-open': One or more interlock devices on the Printer are
      unlocked, equivalent to a prtCoverStatus [RFC3805] of 5
      (interlockOpen).

   o  'interpreter-resource-unavailable': An interpreter resource is
      unavailable (i.e., font, form).

   o  'marker-supply-empty: The device is out of at least one marker
      supply, e.g., toner, ink, ribbon.

   o  'marker-supply-low': The device is low on at least one marker
      supply, e.g., toner, ink, ribbon.

   o  'marker-waste-almost-full': The device marker supply waste
      receptacle is almost full.

   o  'marker-waste-full': The device marker supply waste receptacle is
      full.

   o  'media-empty': At least one input tray is empty, equivalent to a
      prtInputStatus [RFC3805] of 19 (the sum of "Unavailable because
      Broken" (3) and "Critical Alerts" (16)).

   o  'media-jam': The device has a media jam, equivalent to a
      prtInputStatus [RFC3805] of 19 (the sum of "Unavailable because
      Broken" (3) and "Critical Alerts" (16)).

   o  'media-low': At least one input tray is low on media, equivalent
      to a prtInputStatus [RFC3805] of 8 (Non-Critical Alerts).





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   o  'media-needed': A tray has run out of media, equivalent to a
      prtInputStatus [RFC3805] value of 17 (the sum of "Unavailable and
      OnRequest" (1) and "Critical Alerts" (16)).

   o  'moving-to-paused': Someone has paused the Printer using the
      Pause-Printer operation (see Section 4.2.7) or other means, but
      the device(s) is taking an appreciable time to stop.  Later, when
      all output has stopped, "printer-state" becomes 'stopped', and the
      'paused' value replaces the 'moving-to-paused' value in the
      "printer-state-reasons" attribute.  This value MUST be supported
      if the Pause-Printer operation is supported and the implementation
      takes significant time to pause a device in certain circumstances.

   o  'opc-life-over': The optical photo conductor is no longer
      functioning, equivalent to a prtMarkerStatus [RFC3805] of 19
      (the sum of "Unavailable because Broken" (3) and
      "Critical Alerts" (16)).

   o  'opc-near-eol': The optical photo conductor is near its end of
      life, equivalent to a prtMarkerStatus [RFC3805] of 8 (Non-Critical
      Alerts).

   o  'output-area-almost-full': One or more output areas are almost
      full, e.g., tray, stacker, collator, equivalent to a
      prtOutputStatus [RFC3805] of 8 (Non-Critical Alerts).

   o  'output-area-full': One or more output areas are full, e.g., tray,
      stacker, collator, equivalent to a prtInputStatus [RFC3805] of 19
      (the sum of "Unavailable because Broken" (3) and
      "Critical Alerts" (16)).

   o  'output-tray-missing': One or more output trays are not in the
      device, equivalent to a prtOutputStatus [RFC3805] of 19 (the sum
      of "Unavailable because Broken" (3) and "Critical Alerts" (16)).

   o  'paused': Someone has paused the Printer using the Pause-Printer
      operation (see Section 4.2.7) or other means, and the Printer's
      "printer-state" is 'stopped'.  In this state, a Printer MUST NOT
      produce printed output, but it MUST perform other operations
      requested by a Client.  If a Printer had been printing a Job when
      the Printer was paused, the Printer MUST resume printing that Job
      when the Printer is no longer paused and leave no evidence in the
      printed output of such a pause.  This value MUST be supported if
      the Pause-Printer operation is supported.







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   o  'shutdown': Someone has removed a Printer from service, and the
      device can be powered down or physically removed.  In this state,
      a Printer MUST NOT produce printed output, and unless the Printer
      is realized by a print server that is still active, the Printer
      MUST perform no other operations requested by a Client, including
      returning this value.  If a Printer had been printing a Job when
      it was shut down, the Printer MAY resume printing that Job when
      the Printer is restarted.  If the Printer resumes printing such a
      Job, it can leave evidence in the printed output of such a
      shutdown, e.g., the part printed before the shutdown can be
      printed a second time after the shutdown.

   o  'spool-area-full': The limit of persistent storage allocated for
      spooling has been reached.  The Printer is temporarily unable to
      accept more Jobs.  The Printer will remove this value when it is
      able to accept more Jobs.  This value SHOULD be used by a
      non-spooling Printer that only accepts one or a small number of
      Jobs at a time or by a spooling Printer that has filled the spool
      space.

   o  'stopped-partly': When a Printer controls more than one Output
      Device, this reason indicates that one or more Output Devices are
      stopped.  If the reason is a report, fewer than half of the Output
      Devices are stopped.  If the reason is a warning, fewer than all
      of the Output Devices are stopped.

   o  'stopping': The Printer is in the process of stopping the device
      and will be stopped in a while.  When the device is stopped, the
      Printer will change the Printer's state to 'stopped'.  The
      'stopping-warning' reason is never an error, even for a Printer
      with a single Output Device.  When an Output Device ceases
      accepting Jobs, the Printer will have this reason while the Output
      Device completes printing.

   o  'timed-out': The server was able to connect to the Output Device
      (or is always connected) but was unable to get a response from the
      Output Device.

   o  'toner-empty': The device is out of toner.

   o  'toner-low': The device is low on toner.










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5.4.13.  printer-state-message (text(MAX))

   This RECOMMENDED Printer attribute specifies information about the
   "printer-state" and "printer-state-reasons" attributes in human-
   readable text.  If the Printer supports this attribute, the Printer
   MUST be able to generate this message in any of the natural languages
   identified by the Printer's "generated-natural-language-supported"
   attribute (see the "attributes-natural-language" operation attribute
   specified in Section 4.1.4.1).

5.4.14.  ipp-versions-supported (1setOf type2 keyword)

   This REQUIRED attribute identifies the IPP version(s) that this
   Printer supports, including major and minor versions, i.e., the
   version numbers for which this Printer implementation meets the
   conformance requirements.  For version number validation, the Printer
   matches the (2-octet binary) "version-number" parameter supplied by
   the Client in each request (see Sections 4.1.1 and 4.1.8) with the
   (US-ASCII) 'keyword' values of this attribute.

   The following standard 'keyword' values are defined in this document:

   o  '1.0': Meets the conformance requirements of IPP version 1.0 as
      specified in RFC 2566 [RFC2566] and RFC 2565 [RFC2565], including
      any extensions registered according to Section 7 and any extension
      defined in this version or any future version of the IPP Model and
      Semantics document (this document) or the IPP Encoding and
      Transport document [RFC8010] following the rules, if any, when the
      "version-number" parameter is '1.0'.

   o  '1.1': Meets the conformance requirements of IPP version 1.1 as
      specified in this document and [RFC8010], including any extensions
      registered according to Section 7 and any extension defined in any
      future versions of this document or [RFC8010] following the rules,
      if any, when the "version-number" parameter is '1.1'.

   Additional values are defined in "IPP Version 2.0, 2.1, and 2.2"
   [PWG5100.12].

5.4.15.  operations-supported (1setOf type2 enum)

   This REQUIRED Printer attribute specifies the set of supported
   operations for this Printer and contained Jobs.

   This attribute is encoded as any other enum attribute syntax
   according to [RFC8010] as 32 bits.  However, all 32-bit enum values
   for this attribute MUST NOT exceed 0x00007fff, since these same
   values are also passed in two octets in the "operation-id" field (see



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   Section 4.1.1) in each Protocol request with the two high-order
   octets omitted in order to indicate the operation being performed
   [RFC8010].

   Table 19 lists the "operations-supported" attribute and
   "operation-id" parameter (see Section 4.1.2) enum values that are
   defined in this document.

   +---------------+---------------------------------------------------+
   | Value         | Operation Name                                    |
   +---------------+---------------------------------------------------+
   | 0x0000        | reserved, not used                                |
   +---------------+---------------------------------------------------+
   | 0x0001        | reserved, not used                                |
   +---------------+---------------------------------------------------+
   | 0x0002        | Print-Job                                         |
   +---------------+---------------------------------------------------+
   | 0x0003        | Print-URI                                         |
   +---------------+---------------------------------------------------+
   | 0x0004        | Validate-Job                                      |
   +---------------+---------------------------------------------------+
   | 0x0005        | Create-Job                                        |
   +---------------+---------------------------------------------------+
   | 0x0006        | Send-Document                                     |
   +---------------+---------------------------------------------------+
   | 0x0007        | Send-URI                                          |
   +---------------+---------------------------------------------------+
   | 0x0008        | Cancel-Job                                        |
   +---------------+---------------------------------------------------+
   | 0x0009        | Get-Job-Attributes                                |
   +---------------+---------------------------------------------------+
   | 0x000a        | Get-Jobs                                          |
   +---------------+---------------------------------------------------+
   | 0x000b        | Get-Printer-Attributes                            |
   +---------------+---------------------------------------------------+
   | 0x000c        | Hold-Job                                          |
   +---------------+---------------------------------------------------+
   | 0x000d        | Release-Job                                       |
   +---------------+---------------------------------------------------+
   | 0x000e        | Restart-Job                                       |
   +---------------+---------------------------------------------------+
   | 0x000f        | reserved for a future operation                   |









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   +---------------+---------------------------------------------------+
   | 0x0010        | Pause-Printer                                     |
   +---------------+---------------------------------------------------+
   | 0x0011        | Resume-Printer                                    |
   +---------------+---------------------------------------------------+
   | 0x0012        | Purge-Jobs                                        |
   +---------------+---------------------------------------------------+
   | 0x0013-0x3fff | additional registered operations (see the IANA    |
   |               | IPP registry and Section 7.8)                     |
   +---------------+---------------------------------------------------+
   | 0x4000-0x7fff | reserved for vendor extensions (see Section 7.8)  |
   +---------------+---------------------------------------------------+

               Table 19: "operations-supported" Enum Values

5.4.16.  multiple-document-jobs-supported (boolean)

   This RECOMMENDED Printer attribute indicates whether the Printer
   supports more than one Document per Job, i.e., more than one
   Send-Document operation with Document data and/or Send-URI
   operations.  If the Printer supports the Create-Job and Send-Document
   operations (see Sections 4.2.4 and 4.3.1), it MUST support this
   attribute.

5.4.17.  charset-configured (charset)

   This REQUIRED Printer attribute identifies the charset that the
   Printer has been configured to represent 'text' and 'name' Printer
   attributes that are set by the Operator, Administrator, or
   manufacturer, i.e., for "printer-name" (name), "printer-location"
   (text), "printer-info" (text), and "printer-make-and-model" (text).
   Therefore, the value of the Printer's "charset-configured" attribute
   MUST also be among the values of the Printer's "charset-supported"
   attribute.

5.4.18.  charset-supported (1setOf charset)

   This REQUIRED Printer attribute identifies the set of charsets that
   the Printer and contained Jobs support in attributes with attribute
   syntaxes 'text' and 'name'.  At least the value 'utf-8' MUST be
   present, since IPP objects MUST support the UTF-8 [RFC3629] charset.
   If a Printer supports a charset, it means that for all attributes of
   syntaxes 'text' and 'name' the Printer MUST (1) accept the charset in
   requests and (2) return the charset in responses as needed.

   If more charsets than UTF-8 are supported, the Printer MUST perform
   charset conversion between the charsets as described in
   Section 4.1.4.2.



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5.4.19.  natural-language-configured (naturalLanguage)

   This REQUIRED Printer attribute identifies the natural language that
   the Printer has been configured to represent 'text' and 'name'
   Printer attributes that are set by the Operator, Administrator, or
   manufacturer, i.e., for "printer-name" (name), "printer-location"
   (text), "printer-info" (text), and "printer-make-and-model" (text).
   When returning these Printer attributes, the Printer MAY return them
   in the configured natural language specified by this attribute,
   instead of the natural language requested by the Client in the
   "attributes-natural-language" operation attribute.  See
   Section 4.1.4.1 for the specification of the OPTIONAL support for
   multiple natural languages.  Therefore, the value of the Printer's
   "natural-language-configured" attribute MUST also be among the values
   of the Printer's "generated-natural-language-supported" attribute.

5.4.20.  generated-natural-language-supported (1setOf naturalLanguage)

   This REQUIRED Printer attribute identifies the natural language(s)
   that the Printer and contained Jobs support in attributes with
   attribute syntaxes 'text' and 'name'.  The natural language(s)
   supported depends on implementation and/or configuration.  Unlike
   charsets, Printers MUST accept requests with any natural language or
   any Natural Language Override whether the natural language is
   supported or not.

   If a Printer supports a natural language, it means that for any of
   the attributes for which the Printer or Job generates messages, i.e.,
   for the "job-state-message" and "printer-state-message" attributes
   and operation messages (see Section 4.1.5) in operation responses,
   the Printer and Job MUST be able to generate messages in any of the
   Printer's supported natural languages.  See Sections 4.1.4, 5.1.2,
   and 5.1.3 for the definitions of 'text' and 'name' attributes in
   operation requests and responses.

   Note: A Printer that supports multiple natural languages often has
   separate catalogs of messages, one for each natural language
   supported.

5.4.21.  document-format-default (mimeMediaType)

   This REQUIRED Printer attribute identifies the Document format that
   the Printer has been configured to assume if the Client does not
   supply a "document-format" operation attribute in any of the
   operation requests that supply Document data.  The standard values
   for this attribute are Internet media types (sometimes called "MIME
   media types").  For further details, see the description of the
   'mimeMediaType' attribute syntax in Section 5.1.10.



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5.4.22.  document-format-supported (1setOf mimeMediaType)

   This REQUIRED Printer attribute identifies the set of Document
   formats that the Printer and contained Jobs can support.  For further
   details, see the description of the 'mimeMediaType' attribute syntax
   in Section 5.1.10.

5.4.23.  printer-is-accepting-jobs (boolean)

   This REQUIRED Printer attribute indicates whether the Printer is
   currently able to accept Jobs, i.e., is accepting Print-Job,
   Print-URI, and Create-Job requests.  If the value is 'true', the
   Printer is accepting Jobs.  If the value is 'false', the Printer is
   currently rejecting any Jobs submitted to it.  In this case, the
   Printer returns the 'server-error-not-accepting-jobs' status-code.

   This value is independent of the "printer-state" and
   "printer-state-reasons" attributes because its value does not affect
   the current Job; rather, it affects future Jobs.  This attribute,
   when 'false', causes the Printer to reject Jobs even when
   "printer-state" is 'idle' or, when 'true', causes the Printer to
   accept Jobs even when "printer-state" is 'stopped'.

5.4.24.  queued-job-count (integer(0:MAX))

   This REQUIRED Printer attribute contains a count of the number of
   Jobs that are either 'pending', 'processing', 'pending-held', or
   'processing-stopped' and is set by the Printer.

5.4.25.  printer-message-from-operator (text(127))

   This Printer attribute provides a message from an Operator,
   Administrator, or "intelligent" process to indicate to the End User
   information or status of the Printer, such as why it is unavailable
   or when it is expected to be available.

5.4.26.  color-supported (boolean)

   This RECOMMENDED Printer attribute identifies whether the device is
   capable of any type of color printing at all, including highlight
   color.  All Document instructions having to do with color are
   embedded within the Document PDL, although IPP attributes can affect
   the rendering of those colors.

   Note: End Users are able to determine the nature and details of the
   color support by querying the "printer-more-info-manufacturer"
   Printer attribute.




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5.4.27.  reference-uri-schemes-supported (1setOf uriScheme)

   This Printer attribute specifies which URI schemes are supported for
   use in the "document-uri" operation attribute of the Print-URI or
   Send-URI operations.  If a Printer supports these OPTIONAL
   operations, it MUST support the "reference-uri-schemes-supported"
   Printer attribute with at least the following URI scheme value:

   o  'ftp': The Printer will use an FTP 'get' operation as defined in
      [RFC959] using FTP URLs as defined by [RFC3986].

   The Printer MAY support other URI schemes (see Section 5.1.7).

5.4.28.  pdl-override-supported (type2 keyword)

   This REQUIRED Printer attribute expresses the ability of a particular
   Printer implementation to override Document data instructions with
   IPP attributes.  The following 'keyword' values are defined in this
   document:

   o  'attempted': This value indicates that the Printer attempts to
      make the IPP attribute values take precedence over embedded
      instructions in the Document data; however, there is no guarantee.

   o  'not-attempted': This value indicates that the Printer makes no
      attempt to make the IPP attribute values take precedence over
      embedded instructions in the Document data.

   Appendix C contains a full description of how this attribute
   interacts with and affects other IPP attributes, especially the
   "ipp-attribute-fidelity" attribute.

5.4.29.  printer-up-time (integer(1:MAX))

   This REQUIRED Printer attribute indicates the amount of time (in
   seconds) that this Printer instance has been up and running.  The
   value is a monotonically increasing value starting from 1 when the
   Printer is started up (initialized, booted, etc.).  This value is
   used to populate the Event Time Job Status attributes
   "time-at-creation", "time-at-processing", and "time-at-completed"
   (see Section 5.3.14).










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   If the Printer goes down at some value 'n' and comes back up, the
   implementation MAY:

   1.  know how long it has been down and resume at some value greater
       than 'n', or

   2.  restart from 1.

   In other words, if the device or devices that the Printer is
   representing are restarted or power-cycled, the Printer MAY continue
   counting this value or MAY reset this value to 1, depending on
   implementation.  However, if the Printer software ceases running and
   restarts without knowing the last value for "printer-up-time", the
   implementation MUST reset this value to 1.  If this value is reset
   and the Printer has persistent Jobs, the Printer MUST reset the
   "time-at-xxx (integer)" Event Time Job Status attributes according to
   Section 5.3.14.  An implementation MAY use both implementation
   alternatives, depending on warm versus cold start, respectively.

5.4.30.  printer-current-time (dateTime|unknown)

   This RECOMMENDED Printer attribute indicates the current date and
   time.  This value is used to populate the Event Time Job Status
   attributes "date-time-at-creation", "date-time-at-processing", and
   "date-time-at-completed" (see Section 5.3.14).

   This value is obtained on a "best effort" basis and in practice does
   not have to be precise in order to be useful.  A Printer
   implementation sets the value of this attribute by obtaining the date
   and time via some implementation-dependent means, such as getting the
   value from a network time server, initialization at time of
   manufacture, or setting by an Administrator.  See [RFC3196] and
   [PWG5100.19] for examples.  If an implementation supports this
   attribute and the implementation knows that it has not yet been set,
   then the implementation MUST return the value of this attribute using
   the out-of-band 'unknown', meaning the value is not yet known.  See
   the beginning of Section 5.1.

   The time zone of this attribute might not be the time zone used by
   people located near the Printer or device.  The Client MUST NOT
   expect the time zone of any received 'dateTime' value to be in the
   time zone of the Client or in the time zone of the people located
   near the Printer.








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   The Client SHOULD display any dateTime attributes to the user in the
   Client's local time by converting the 'dateTime' value returned by
   the server to the time zone of the Client, rather than using the time
   zone returned by the Printer in attributes that use the 'dateTime'
   attribute syntax.

   Note: Prior versions of this document incorrectly specified the use
   of the 'no-value' out-of-band value when the current date and time
   had not been set.  The correct out-of-band value is 'unknown', since
   there is always an intrinsic current date and time.

5.4.31.  multiple-operation-time-out (integer(1:MAX))

   This RECOMMENDED Printer attribute identifies the minimum time (in
   seconds) that the Printer waits for additional Send-Document or
   Send-URI operations to follow a still-open Job before taking any
   recovery actions, such as the ones indicated in Section 4.3.1.  If
   the Printer supports the Create-Job and Send-Document operations (see
   Sections 4.2.4 and 4.3.1), it MUST support this attribute.

   Printers SHOULD use a value between '60' and '240' (seconds).  An
   implementation MAY allow an Administrator to set this attribute by
   means not defined in this document.  If so, the Administrator MAY be
   able to set values outside this range.

5.4.32.  compression-supported (1setOf type2 keyword)

   This REQUIRED Printer attribute identifies the set of supported
   compression algorithms for Document data.  Compression only applies
   to the Document data; compression does not apply to the encoding of
   the IPP operation itself.  The supported values are used to validate
   the Client-supplied "compression" operation attributes in Print-Job
   and Send-Document requests.

   Standard 'keyword' values defined in this document are:

   o  'none': no compression is used.

   o  'deflate': ZIP inflate/deflate compression technology described in
      RFC 1951 [RFC1951].

   o  'gzip': GNU zip compression technology described in RFC 1952
      [RFC1952].

   o  'compress': UNIX compression technology described in RFC 1977
      [RFC1977].





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5.4.33.  job-k-octets-supported (rangeOfInteger(0:MAX))

   This Printer attribute specifies the upper and lower bounds of total
   sizes of Jobs in K octets, i.e., in units of 1024 octets.  The
   supported values are used to validate the Client-supplied
   "job-k-octets" operation attribute in Job Creation requests.  The
   corresponding Job Description attribute "job-k-octets" is defined in
   Section 5.3.17.1.

5.4.34.  job-impressions-supported (rangeOfInteger(0:MAX))

   This RECOMMENDED Printer attribute specifies the upper and lower
   bounds for the number of Impressions per Job.  The supported values
   are used to validate the Client-supplied "job-impressions" operation
   attribute in Job Creation requests.  The corresponding Job
   Description attribute "job-impressions" is defined in
   Section 5.3.17.2.

5.4.35.  job-media-sheets-supported (rangeOfInteger(1:MAX))

   This Printer attribute specifies the upper and lower bounds for the
   number of Media Sheets per Job.  The supported values are used to
   validate the Client-supplied "job-media-sheets" operation attribute
   in Job Creation requests.  The corresponding Job attribute
   "job-media-sheets" is defined in Section 5.3.17.3.

5.4.36.  pages-per-minute (integer(0:MAX))

   This RECOMMENDED Printer attribute specifies the nominal number of
   pages per minute to the nearest whole number that can be generated by
   this Printer (e.g., simplex, black-and-white).  This attribute is
   informative, not a service guarantee.  Generally, it is the value
   used in the marketing literature to describe the speed of the device.

   A value of 0 indicates a device that takes more than two minutes to
   process a page.

5.4.37.  pages-per-minute-color (integer(0:MAX))

   This RECOMMENDED Printer attribute specifies the nominal number of
   pages per minute to the nearest whole number that can be generated by
   this Printer when printing color (e.g., simplex, color).  For
   purposes of this attribute, the meaning of "color" is the same as
   that for the "color-supported" attribute; namely, the device is
   capable of any type of color printing at all, including highlight
   color.  This attribute is informative, not a service guarantee.
   Generally, it is the value used in the marketing literature to
   describe the color capabilities of this device.



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   A value of 0 indicates a device that takes more than two minutes to
   process a page in color.

   If a color device has several color modes, it MAY use the
   "pages-per-minute" value for this attribute that corresponds to the
   mode that produces the highest number.

   Printers that are black-and-white only MUST NOT support this
   attribute.  If this attribute is present, then the "color-supported"
   Printer Description attribute MUST be present and have a 'true'
   value.

   The values of the "pages-per-minute" and "pages-per-minute-color"
   attributes returned by the Get-Printer-Attributes operation MAY be
   affected by the "document-format" attribute supplied by the Client in
   the Get-Printer-Attributes request.  In other words, the
   implementation MAY have different speeds, depending on the Document
   format being processed.  See Section 4.2.5.1 ("Get-Printer-Attributes
   Request").

6.  Conformance

   This section describes conformance issues and requirements.  This
   document introduces model entities such as objects, operations,
   attributes, attribute syntaxes, and attribute values.  The following
   sections describe the conformance requirements that apply to these
   model entities.

6.1.  Client Conformance Requirements

   This section describes the conformance requirements for a Client (see
   Section 3.1), whether it be:

   1.  contained within software controlled by an End User, e.g.,
       activated by the "Print" menu item in an application that sends
       IPP requests, or

   2.  the print server component that sends IPP requests to either an
       Output Device or another "downstream" print server.

   A conforming Client supports all REQUIRED operations as defined in
   this document.  For each attribute included in an operation request,
   a conforming Client MUST supply a value whose type and value syntax
   conforms to the requirements specified in Sections 4 and 5 of this
   document.  A conforming Client MAY supply any Standards Track
   extensions and/or vendor extensions in an operation request, as long
   as the extensions meet the requirements in Section 7.




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   While this document does not define conformance requirements for the
   user interfaces provided by IPP Clients or their applications, best
   practices for user interfaces are defined in [PWG5100.19].

   A Client MUST be able to accept any of the attribute syntaxes defined
   in Section 5.1, including their full range, that can be returned to
   it in a response from a Printer.  In particular, for each attribute
   that the Client supports whose attribute syntax is 'text', the Client
   MUST accept and process both the 'textWithoutLanguage' and
   'textWithLanguage' forms.  Similarly, for each attribute that the
   Client supports whose attribute syntax is 'name', the Client MUST
   accept and process both the 'nameWithoutLanguage' and
   'nameWithLanguage' forms.  For presentation purposes, truncation of
   long attribute values is not recommended.  A recommended approach
   would be for the Client implementation to allow the user to scroll
   through long attribute values.

   A response MAY contain attribute groups, attributes, attribute
   syntaxes, values, and status-code values that the Client does not
   expect.  Therefore, a Client implementation MUST gracefully handle
   such responses and not refuse to interoperate with a conforming
   Printer that is returning Standards Track extensions or vendor
   extensions, including attribute groups, attributes, attribute
   syntaxes, attribute values, status-code values, and out-of-band
   attribute values that conform to Section 7.  Clients can choose to
   ignore any parameters, attribute groups, attributes, attribute
   syntaxes, or values that they do not understand.

   While a Client is sending data to a Printer, it SHOULD do its best to
   prevent a channel from being closed by a lower layer when the channel
   is blocked (i.e., flow-controlled off) for whatever reason, e.g.,
   'out of paper' or 'Job ahead hasn't freed up enough memory'.
   However, the layer that launched the print submission (e.g., an
   End User) MAY close the channel in order to cancel the Job.  When a
   Client closes a channel, a Printer MAY print all or part of the
   received portion of the Document.  See the Encoding and Transport
   document [RFC8010] for more details.

   A Client MUST support Client Authentication as defined in [RFC8010].
   A Client SHOULD support Operation Privacy and Server Authentication
   as defined in [RFC8010].  See also Section 9 of this document.










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6.2.  IPP Object Conformance Requirements

   This section specifies the conformance requirements for conforming
   implementations of IPP objects (see Section 3).  These requirements
   apply to an IPP object whether it is:

   1)  an (embedded) device component that accepts IPP requests and
       controls the device, or

   2)  a component of a print server that accepts IPP requests (where
       the print server controls one or more networked devices using IPP
       or other protocols).

6.2.1.  Objects

   Conforming implementations MUST implement all of the model objects as
   defined in this document in the indicated sections:

   Section 3.1 - Printer Object

   Section 3.2 - Job Object

6.2.2.  Operations

   Conforming IPP object implementations MUST implement all of the
   REQUIRED model operations, including REQUIRED responses, as defined
   in this document in the indicated sections.  Table 20 lists the
   operations for a Printer, while Table 21 lists the operations for
   a Job.






















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         +----------------------------------------+-------------+
         | Operation                              | Conformance |
         +----------------------------------------+-------------+
         | Print-Job (Section 4.2.1)              | REQUIRED    |
         +----------------------------------------+-------------+
         | Print-URI (Section 4.2.2)              | OPTIONAL    |
         +----------------------------------------+-------------+
         | Validate-Job (Section 4.2.3)           | REQUIRED    |
         +----------------------------------------+-------------+
         | Create-Job (Section 4.2.4)             | RECOMMENDED |
         +----------------------------------------+-------------+
         | Get-Printer-Attributes (Section 4.2.5) | REQUIRED    |
         +----------------------------------------+-------------+
         | Get-Jobs (Section 4.2.6)               | REQUIRED    |
         +----------------------------------------+-------------+
         | Pause-Printer (Section 4.2.7)          | OPTIONAL    |
         +----------------------------------------+-------------+
         | Resume-Printer (Section 4.2.8)         | OPTIONAL    |
         +----------------------------------------+-------------+
         | Purge-Jobs (Section 4.2.9)             | SHOULD NOT  |
         +----------------------------------------+-------------+

         Table 20: Conformance Requirements for Printer Operations

           +------------------------------------+-------------+
           | Operation                          | Conformance |
           +------------------------------------+-------------+
           | Send-Document (Section 4.3.1)      | RECOMMENDED |
           +------------------------------------+-------------+
           | Send-URI (Section 4.3.2)           | RECOMMENDED |
           +------------------------------------+-------------+
           | Cancel-Job (Section 4.3.3)         | REQUIRED    |
           +------------------------------------+-------------+
           | Get-Job-Attributes (Section 4.3.4) | REQUIRED    |
           +------------------------------------+-------------+
           | Hold-Job (Section 4.3.5)           | OPTIONAL    |
           +------------------------------------+-------------+
           | Release-Job (Section 4.3.6)        | OPTIONAL    |
           +------------------------------------+-------------+
           | Restart-Job (Section 4.3.7)        | SHOULD NOT  |
           +------------------------------------+-------------+

           Table 21: Conformance Requirements for Job Operations








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   Conforming IPP objects MUST support all REQUIRED operation attributes
   and all values of such attributes if so indicated in the description.
   Conforming IPP objects MUST ignore all unsupported or unknown
   operation attributes or Operation Attributes groups received in a
   request but MUST reject a request that contains a supported operation
   attribute that contains an unsupported value.

   Conforming IPP objects MAY return operation responses that contain
   attribute groups, attribute names, attribute syntaxes, attribute
   values, and status-code values that are extensions to this
   specification.  The additional attribute groups MAY occur in any
   order.

   The following section on object attributes specifies the support
   required for object attributes.

6.2.3.  IPP Object Attributes

   Conforming IPP objects MUST support all of the REQUIRED object
   attributes, as defined in this document in the indicated sections.

   If an object supports an attribute, it MUST support only those values
   specified in this document or through the extension mechanism
   described in Section 6.2.5.  It MAY support any non-empty subset of
   these values.  That is, it MUST support at least one of the specified
   values and at most all of them.

6.2.4.  Versions

   IPP/1.1 Clients MUST meet the conformance requirements for Clients
   specified in this document and [RFC8010].  IPP/1.1 Clients MUST be
   capable of sending requests containing a "version-number" parameter
   with a value of '1.1'.

   IPP/1.1 Printer and Job objects MUST meet the conformance
   requirements for IPP objects specified in this document and
   [RFC8010].  IPP/1.1 objects MUST accept requests containing a
   "version-number" parameter with a '1.1' value or reject the request
   if the operation is not supported.












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   It is beyond the scope of this specification to mandate conformance
   with other IPP versions.  However, IPP was deliberately designed to
   make supporting different versions easy.  IPP/1.1 Printer
   implementations MUST:

   o  decode and process any well-formed IPP/1.1 request, and

   o  respond appropriately with a response containing the same
      "version-number" parameter value used by the Client in the
      request.

   IPP/1.1 Client implementations MUST:

   o  decode and process any well-formed IPP/1.1 response.

   IPP Clients SHOULD try supplying alternate version numbers if they
   receive a 'server-error-version-not-supported' error in a response.

6.2.5.  Extensions

   A conforming IPP object MAY support Standards Track extensions and
   vendor extensions, as long as the extensions meet the requirements
   specified in Section 7.

   For each attribute included in an operation response, a conforming
   IPP object MUST return a value whose type and value syntax conforms
   to the requirements specified in Sections 4 and 5 of this document.

6.2.6.  Attribute Syntaxes

   An IPP object MUST be able to accept any of the attribute syntaxes
   defined in Section 5.1, including their full range, in any operation
   in which a Client can supply attributes or the Administrator can
   configure attributes (by means outside the scope of this IPP/1.1
   document).  In particular, for each attribute that the IPP object
   supports whose attribute syntax is 'text', the IPP object MUST accept
   and process both the 'textWithoutLanguage' and 'textWithLanguage'
   forms.  Similarly, for each attribute that the IPP object supports
   whose attribute syntax is 'name', the IPP object MUST accept and
   process both the 'nameWithoutLanguage' and 'nameWithLanguage' forms.
   Furthermore, an IPP object MUST return attributes to the Client in
   operation responses that conform to the syntaxes specified in
   Section 5.1, including their full range if supplied previously by a
   Client.







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6.2.7.  Security

   An IPP Printer implementation SHOULD contain support for Client
   Authentication as defined in the IPP/1.1 Encoding and Transport
   document [RFC8010].  A Printer implementation MAY allow an
   Administrator to configure the Printer so that all, some, or none of
   the users are authenticated.  See also Section 9 of this document.

   An IPP Printer implementation SHOULD contain support for Operation
   Privacy and Server Authentication as defined in [RFC8010].  A Printer
   implementation MAY allow an Administrator to configure the degree of
   support for Operation Privacy and Server Authentication.  See also
   Section 9 of this document.

   Security MUST NOT be compromised when a Client supplies a lower
   "version-number" parameter in a request.  For example, if a Printer
   conforming to IPP/1.1 accepts version '1.0' requests and is
   configured to enforce Digest Authentication, it MUST do the same for
   a version '1.0' request.

6.3.  Charset and Natural Language Requirements

   All Clients and IPP objects MUST support the 'utf-8' charset as
   defined in Section 5.1.8.

   IPP objects MUST be able to accept any Client request that correctly
   uses the "attributes-natural-language" operation attribute or the
   Natural Language Override mechanism on any individual attribute
   whether or not the natural language is supported by the IPP object.
   If an IPP object supports a natural language, then it MUST be able to
   translate (perhaps by table lookup) all generated 'text' or 'name'
   attribute values into one of the supported languages (see
   Section 4.1.4).


















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7.  IANA Considerations

   This section describes the procedures for defining Standards Track
   and vendor extensions to this document.  This affects the following
   subregistries of the IANA IPP registry:

   1.  Objects

   2.  Attributes

   3.  Keyword Attribute Values

   4.  Enum Attribute Values

   5.  Attribute Group Tags

   6.  Out-of-Band Attribute Value Tags

   7.  Attribute Syntaxes

   8.  Operations

   9.  Status-Code Values

   Extensions registered for use with IPP are OPTIONAL for Client and
   IPP object conformance to the IPP/1.1 Model and Semantics document
   (this document).

   These extension procedures are aligned with the guidelines as set
   forth in "Guidelines for Writing an IANA Considerations Section in
   RFCs" [RFC5226].  Appendix A describes how to propose new
   registrations for consideration.  IANA will reject registration
   proposals that leave out required information or do not follow the
   appropriate format described in Appendix A.  The IPP/1.1 Model and
   Semantics document can also be extended by an appropriate
   Standards Track document that specifies any of the above extensions.

   The IANA policy (using terms defined in [RFC5226]) for all extensions
   is Specification Required, Expert Review, or First Come First Served
   as documented in the following subsections.  Registrations submitted
   to IANA are forwarded to the IPP Designated Expert(s) who reviews the
   proposal on a mailing list that the Designated Expert(s) keeps for
   this purpose.  Initially, that list is the mailing list used by the
   PWG IPP WG:

      ipp@pwg.org





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   The IPP Designated Expert(s) is appointed by the IESG Area Director
   responsible for IPP, according to [RFC5226].

   In addition, the IANA-PRINTER-MIB [RFC3805] has been updated to
   reference this document; the current version is available from
   <http://www.iana.org>.

7.1.  Object Extensions

   The IANA policy (using terms defined in [RFC5226]) for object
   extensions was formerly Expert Review; this document changes the
   policy to Specification Required.

7.2.  Attribute Extensibility

   Since attribute names are type2 keywords (see Section 5.1.4), the
   IANA policy (using terms defined in [RFC5226]) for attribute
   extensions is Expert Review.

   For vendor attribute extensions, implementors SHOULD use keywords
   with a suitable distinguishing prefix such as 'smiNNN-' where NNN is
   an SMI Private Enterprise Number (PEN) [IANA-PEN].  For example, if
   the company Example Corp. had obtained the SMI PEN 32473, then a
   vendor attribute 'foo' would be 'smi32473-foo'.

      Note: Prior versions of this document recommended using a fully
      qualified domain name [RFC1035] as the prefix (e.g.,
      'example.com-foo'), and many IPP implementations have also used
      reversed domain names (e.g., 'com.example-foo').  Domain names
      have proven problematic due to the length of some domain names,
      parallel use of country-specific domain names (e.g.,
      'example.co.jp-foo'), and changes in ownership of domain names.

   If a new Printer attribute is defined and its values can be affected
   by a specific Document format, its specification needs to contain the
   following sentence:

      "The value of this attribute returned in a Get-Printer-Attributes
      response MAY depend on the "document-format" attribute supplied
      (see Section 4.2.5.1) of the IPP/1.1 Model and Semantics
      document."

   If the specification does not, then its value in the
   Get-Printer-Attributes response MUST NOT depend on the
   "document-format" attribute supplied in the request.






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   When a new Job Template attribute is registered, the value of the
   Printer attributes MAY vary with "document-format" supplied in the
   request without the specification having to indicate so.

7.3.  Keyword Extensibility

   The IANA policy (using terms defined in [RFC5226]) for type1 keyword
   extensions is Specification Required.  The IANA policy for type2
   keyword extensions is Expert Review.  The IANA policy for vendor
   keyword extensions is First Come First Served.  Only attributes using
   the type1 and type2 keyword syntax can be registered in the IANA IPP
   registry.

      Note: The type1 or type2 prefix on the basic attribute syntax is
      provided only to communicate the IANA policy required for
      registration and is not represented in IPP messages.  Both type1
      and type2 'keyword' values are represented using the same
      'keyword' value tag.

   For type1 and type2 keywords, the proposer includes the name of the
   keyword in the registration proposal, and the name is part of the
   technical review.

   For vendor keyword extensions, implementors SHOULD either:

   a.  follow attribute-specific guidance such as the guidance defined
       in [PWG5101.1], or

   b.  use keywords with a suitable distinguishing prefix, such as
       'smiNNN-' where NNN is an SMI Private Enterprise Number (PEN)
       [IANA-PEN].

   For example, if the company Example Corp. had obtained the
   SMI PEN 32473, then a vendor keyword 'foo' would be 'smi32473-foo'.

      Note: Prior versions of this document recommended using a fully
      qualified domain name [RFC1035] as the prefix (e.g.,
      'example.com-foo'), and many IPP implementations have also used
      reversed domain names (e.g., 'com.example-foo').  Domain names
      have proven problematic due to the length of some domain names,
      parallel use of country-specific domain names (e.g.,
      'example.co.jp-foo'), and changes in ownership of domain names.

   When a type2 keyword extension is approved, the IPP Designated
   Expert(s) becomes the point of contact for any future maintenance
   that might be required for that registration.





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7.4.  Enum Extensibility

   The IANA policy (using terms defined in [RFC5226]) for type1 enum
   extensions is Specification Required.  The IANA policy for type2 enum
   extensions is Expert Review.  The IANA policy for vendor enum
   extensions is First Come First Served.  Only attributes using the
   type1 and type2 enum syntax can be registered in the IANA IPP
   registry.

      Note: The type1 or type2 prefix on the basic attribute syntax is
      provided only to communicate the IANA policy required for
      registration and is not represented in IPP messages.  Both type1
      and type2 enum values are represented using the same enum
      value tag.

   For vendor enum extensions, implementors MUST use values in the
   reserved integer range, which is 0x40000000 to 0x7fffffff.
   Implementors SHOULD consult with the IPP Designated Expert(s) to
   reserve vendor extension value(s) for their usage.

   When a type1 or type2 enum extension is approved, the IPP Designated
   Expert(s), in consultation with IANA, assigns the next available enum
   number for each enum value.

   When a type2 enum extension is approved, the IPP Designated Expert(s)
   becomes the point of contact for any future maintenance that might be
   required for that registration.

7.5.  Attribute Group Extensibility

   The IANA policy (using terms defined in [RFC5226]) for attribute
   group extensions was formerly Expert Review; this document changes
   the policy to Specification Required.

   For attribute groups, the IPP Designated Expert(s), in consultation
   with IANA, assigns the next attribute group tag code in the
   appropriate range as specified in [RFC8010].

7.6.  Out-of-Band Attribute Value Extensibility

   The IANA policy (using terms defined in [RFC5226]) for out-of-band
   attribute value extensions was formerly Expert Review; this document
   changes the policy to Specification Required.

   For out-of-band attribute value tags, the IPP Designated Expert(s),
   in consultation with IANA, assigns the next out-of-band attribute
   value tag code in the appropriate range as specified in [RFC8010].




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7.7.  Attribute Syntax Extensibility

   The IANA policy (using terms defined in [RFC5226]) for attribute
   syntax extensions was formerly Expert Review; this document changes
   the policy to Specification Required.  The IANA policy for vendor
   attribute syntax extensions (tags 0x40000000 to 0x7fffffff) is First
   Come First Served.  Only attribute syntaxes in the range of
   0x00000000 to 0x3fffffff can be registered in the IANA IPP registry.

   For vendor attribute syntax extensions, implementors MUST use values
   in the reserved integer range, which is 0x40000000 to 0x7fffffff.
   Implementors SHOULD consult with the IPP Designated Expert(s) to
   reserve vendor extension value(s) for their usage.

   For registered attribute syntaxes, the IPP Designated Expert(s), in
   consultation with IANA, assigns the next attribute syntax tag in the
   appropriate range as specified in [RFC8010].

7.8.  Operation Extensibility

   The IANA policy (using terms defined in [RFC5226]) for operation
   extensions is Expert Review.  The IANA policy for vendor operation
   extensions (values 0x4000 to 0x7fff) is First Come First Served.
   Only operation codes in the range of 0x0000 to 0x3fff can be
   registered in the IANA IPP registry.

   For vendor operation extensions, implementors MUST use values in the
   reserved integer range, which is 0x4000 to 0x7fff.  Implementors
   SHOULD consult with the IPP Designated Expert(s) to reserve vendor
   extension value(s) for their usage.

   For registered operation extensions, the IPP Designated Expert(s), in
   consultation with IANA, assigns the next "operation-id" code as
   specified in Section 5.4.15.

















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7.9.  Status-Code Extensibility

   The IANA policy (using terms defined in [RFC5226]) for status-code
   extensions is Expert Review.  The IANA policy for vendor status-code
   extensions (codes 0x0n80 to 0x0nff, for n = 0 to 5) is First Come
   First Served.  Only status-code values in the range of 0x0n00 to
   0x0n7f can be registered in the IANA IPP registry.

   The status-code values are allocated in ranges as specified in
   Appendix B for each status-code class:

   "informational" - Request received, continuing process

   "successful" - The action was successfully received, understood, and
   accepted

   "redirection" - Further action is taken in order to complete the
   request

   "client-error" - The request contains bad syntax or cannot be
   fulfilled

   "server-error" - The IPP object failed to fulfill an apparently valid
   request

   For vendor operation status-code extensions, implementors MUST use
   the top of each range (0x0n80 to 0x0nff) as specified in Appendix B.
   Implementors SHOULD consult with the IPP Designated Expert(s) to
   reserve vendor extension value(s) for their usage.

   For registered operation status-code values, the IPP Designated
   Expert(s), in consultation with IANA, assigns the next status-code in
   the appropriate class range as specified in Appendix B.


















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8.  Internationalization Considerations

   Some of the attributes have values that are text strings and names
   that are intended for human understanding rather than machine
   understanding (see the 'text' and 'name' attribute syntaxes in
   Sections 5.1.2 and 5.1.3).

   In each operation request, the Client

   o  identifies the charset and natural language of the request that
      affects each supplied 'text' and 'name' attribute value, and

   o  requests the charset and natural language for attributes returned
      by the IPP object in operation responses (as described in
      Section 4.1.4.1).

   In addition, the Client MAY separately and individually identify the
   Natural Language Override of a supplied 'text' or 'name' attribute
   using the 'textWithLanguage' and 'nameWithLanguage' techniques
   described in Sections 5.1.2.2 and 5.1.3.2, respectively.

   All IPP objects MUST support the UTF-8 [RFC3629] charset in all
   'text' and 'name' attributes supported.  If an IPP object supports
   more than the UTF-8 charset, the object MUST convert between them in
   order to return the requested charset to the Client according to
   Section 4.1.4.2.  If an IPP object supports more than one natural
   language, the object SHOULD return 'text' and 'name' values in the
   natural language requested where those values are generated by the
   Printer (see Section 4.1.4.1).

   For Printers that support multiple charsets and/or multiple natural
   languages in 'text' and 'name' attributes, different Jobs might have
   been submitted in differing charsets and/or natural languages.  All
   responses MUST be returned in the charset requested by the Client.
   However, the Get-Jobs operation uses the 'textWithLanguage' and
   'nameWithLanguage' mechanisms to identify the differing natural
   languages with each Job attribute returned.

   The Printer also has configured charset and natural language
   attributes.  The Client can query the Printer to determine the list
   of charsets and natural languages supported by the Printer and what
   the Printer's configured values are.  See the "charset-configured",
   "charset-supported", "natural-language-configured", and
   "generated-natural-language-supported" Printer Description attributes
   for more details.






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   The "charset-supported" attribute identifies the supported charsets.
   If a charset is supported, the IPP object MUST be capable of
   converting to and from that charset into any other supported charset.
   In many cases, an IPP object will support only one charset, and it
   MUST be the UTF-8 charset.

   The "charset-configured" attribute identifies the one supported
   charset that is the native charset, given the current configuration
   of the IPP object (Administrator defined).

   The "generated-natural-language-supported" attribute identifies the
   set of supported natural languages for generated messages; it is not
   related to the set of natural languages that MUST be accepted for
   Client-supplied 'text' and 'name' attributes.  For Client-supplied
   'text' and 'name' attributes, an IPP object MUST accept ALL supplied
   natural languages.  For example, if a Client supplies a Job name that
   is in 'fr-ca' but the Printer only generates 'en-us', the Printer
   object MUST still accept the Job name value.

   The "natural-language-configured" attribute identifies the one
   supported natural language for generated messages that is the native
   natural language, given the current configuration of the IPP object
   (Administrator defined).

   Attributes of types 'text' and 'name' are populated from different
   sources.  These attributes can be categorized into the following
   groups (depending on the source of the attribute):

   1.  Some attributes are supplied by the Client (e.g., the
       Client-supplied "job-name", "document-name", and
       "requesting-user-name" operation attributes along with the
       corresponding Job's "job-name" and "job-originating-user-name"
       attributes).  The IPP object MUST accept these attributes in any
       natural language no matter what the set of supported languages
       for generated messages.

   2.  Some attributes are supplied by the Administrator (e.g., the
       Printer's "printer-name" and "printer-location" attributes).
       These can also be in any natural language.  If the natural
       language for these attributes is different than what a Client
       requests, then they MUST be reported using the Natural Language
       Override mechanism.









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   3.  Some attributes are supplied by the device manufacturer (e.g.,
       the Printer's "printer-make-and-model" attribute).  These can
       also be in any natural language.  If the natural language for
       these attributes is different than what a Client requests, then
       they MUST be reported using the Natural Language Override
       mechanism.

   4.  Some attributes are supplied by the Operator (e.g., the Job's
       "job-message-from-operator" attribute).  These can also be in any
       natural language.  If the natural language for these attributes
       is different than what a Client requests, then they MUST be
       reported using the Natural Language Override mechanism.

   5.  Some attributes are generated by the IPP object (e.g., the Job's
       "job-state-message" attribute, the Printer's
       "printer-state-message" attribute, and the "status-message"
       operation attribute).  These attributes can only be in one of the
       "generated-natural-language-supported" natural languages.  If a
       Client requests some natural language for these attributes other
       than one of the supported values, the IPP object SHOULD respond
       using the value of the "natural-language-configured" attribute
       (using the Natural Language Override mechanism if needed).

   The 'text' and 'name' attributes specified in this version of this
   document (additional ones will be registered according to the
   procedures in Section 7) are shown in Table 22.

   +-----------------------------------+-------------------------------+
   | Attributes                        | Source                        |
   +-----------------------------------+-------------------------------+
   | Operation Attributes:             |                               |
   |                                   |                               |
   | job-name (name)                   | Client                        |
   | document-name (name)              | Client                        |
   | requesting-user-name (name)       | Client                        |
   | status-message (text)             | Job or Printer                |
   | detailed-status-message (text)    | Job or Printer (note 1)       |
   | document-access-error (text)      | Job or Printer (note 1)       |
   |                                   |                               |
   | Job Template Attributes:          |                               |
   |                                   |                               |
   | job-hold-until (keyword | name)   | Client matches Administrator- |
   |                                   | configured                    |
   | job-hold-until-default (keyword | | Client matches Administrator- |
   | name)                             | configured                    |
   | job-hold-until-supported (keyword | Client matches Administrator- |
   | | name)                           | configured                    |




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   | job-sheets (keyword | name)       | Client matches Administrator- |
   |                                   | configured                    |
   | job-sheets-default (keyword |     | Client matches Administrator- |
   | name)                             | configured                    |
   | job-sheets-supported (keyword |   | Client matches Administrator- |
   | name)                             | configured                    |
   | media (keyword | name)            | Client matches Administrator- |
   |                                   | configured                    |
   | media-default (keyword | name)    | Client matches Administrator- |
   |                                   | configured                    |
   | media-supported (keyword | name)  | Client matches Administrator- |
   |                                   | configured                    |
   | media-ready (keyword | name)      | Client matches Administrator- |
   |                                   | configured                    |
   |                                   |                               |
   | Job Description Attributes:       |                               |
   |                                   |                               |
   | job-name (name)                   | Client or Printer             |
   | job-originating-user-name (name)  | Printer                       |
   | job-state-message (text)          | Job or Printer                |
   | output-device-assigned            | Administrator                 |
   | (name(127))                       |                               |
   | job-message-from-operator         | Operator                      |
   | (text(127))                       |                               |
   | job-detailed-status-messages      | Job or Printer (note 1)       |
   | (1setOf text)                     |                               |
   | job-document-access-errors        | Job or Printer (note 1)       |
   | (1setOf text)                     |                               |
   |                                   |                               |
   | Printer Description Attributes:   |                               |
   |                                   |                               |
   | printer-name (name(127))          | Administrator                 |
   | printer-location (text(127))      | Administrator                 |
   | printer-info (text(127))          | Administrator                 |
   | printer-make-and-model            | Administrator or manufacturer |
   | (text(127))                       |                               |
   | printer-state-message (text)      | Printer                       |
   | printer-message-from-operator     | Operator                      |
   | (text(127))                       |                               |
   +-----------------------------------+-------------------------------+

                  Table 22: 'text' and 'name' Attributes

   Note 1: Neither the Printer nor the Client localizes these message
   attributes, since they are intended for use by the Administrator or
   other experienced technical persons.





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9.  Security Considerations

   It is difficult to anticipate the security risks that might exist in
   any given IPP environment.  For example, if IPP is used within a
   given small business over a private LAN with physical security, the
   risks of exposing Document data can be low enough that the business
   will choose not to use encryption on that data.  However, if the
   connection between the Client and the IPP object is over a public
   network, the Client can protect the content of the information during
   transmission through the network with encryption.

   Furthermore, the value of the information being printed can vary from
   one IPP environment to the next.  Printing payroll checks, for
   example, would have a different value than printing public
   information from a file.  There is also the possibility of denial-of-
   service attacks, but denial-of-service attacks against printing
   resources are not well understood, and there are no published
   precedents regarding this scenario.

   Once the authenticated identity of the requester has been supplied to
   the IPP object, the object uses that identity to enforce any
   authorization policy that might be in place.  For example, one site's
   policy might be that only the Job owner is allowed to cancel a Job.
   The details and mechanisms to set up a particular access control
   policy are not part of this document and are typically established
   via some other type of administrative or access control framework.
   However, there are operation status-code values that allow an IPP
   server to return information back to a Client about any potential
   access control violations for an IPP object.

   During a Job Creation request, the Client's identity is recorded in
   the Job object in an implementation-defined attribute.  This
   information can be used to verify a Client's identity for subsequent
   operations on that Job object in order to enforce any access control
   policy that might be in effect.  See Section 9.3 below for more
   details.  This and other information stored in the Job object can
   also be considered personal or sensitive in nature and can be
   filtered out as part of a configured privacy policy (Section 9.4).

   Since the security levels or the specific threats that an
   Administrator can be concerned with cannot be anticipated, IPP
   implementations MUST be capable of operating with different security
   mechanisms and security policies as required by the individual
   installation.  Security policies might vary from very strong to very
   weak, or to none at all, and corresponding security mechanisms will
   be required.





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9.1.  Security Scenarios

   The following sections describe specific security attacks for IPP
   environments.  Where examples are provided, they are illustrative of
   the environment and not an exhaustive set.

9.1.1.  Client and Server in the Same Security Domain

   This environment is typical of internal networks where traditional
   office workers print the output of personal productivity applications
   on shared workgroup Printers, or where batch applications print their
   output on large production Printers.  Although the identity of the
   user has been authenticated and can be trusted in this environment, a
   user might want to protect the content of a Document against such
   attacks as eavesdropping, replaying, or tampering by using a secure
   transport such as TLS [RFC5246].

9.1.2.  Client and Server in Different Security Domains

   Examples of this environment include printing a Document created by
   the Client on a publicly available Printer, such as at a commercial
   print shop, or printing a Document remotely on a business associate's
   Printer.  This latter operation is functionally equivalent to sending
   the Document to the business associate as a facsimile.  Printing
   sensitive information on a Printer in a different security domain
   requires strong security measures.  In this environment,
   authentication of the Printer is required as well as protection
   against unauthorized use of print resources.  Since the Document
   crosses security domains, protection against eavesdropping and
   Document tampering is also required.  It will also be important in
   this environment to protect Printers against "spamming" and malicious
   Document content -- authentication and Document data pre-scanning can
   be used to minimize those threats.

9.1.3.  Print by Reference

   When the Document is not stored on the Client, printing can be done
   by reference.  That is, the print request can contain a reference, or
   pointer, to the Document instead of the actual Document itself -- see
   Sections 4.2.2 and 4.3.2.  Standard methods currently do not exist
   for remote entities to "assume" the credentials of a Client for
   forwarding requests to a third party.  It is anticipated that print
   by reference will be used to access "public" Documents.  Note that
   sophisticated methods for authenticating "proxies" are beyond the
   scope of this IPP/1.1 document.  Because Printers typically process
   Jobs serially, print by reference is not seen as a serious denial-of-
   service threat to the referenced servers.




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9.2.  URIs in Operation, Job, and Printer Attributes

   The "printer-uri-supported" attribute contains the Printer's URI(s).
   Its companion attribute, "uri-security-supported", identifies the
   security mechanism used for each URI listed in the
   "printer-uri-supported" attribute.  For each Printer operation
   request, a Client MUST supply only one URI in the "printer-uri"
   operation attribute.  In other words, even though the Printer
   supports more than one URI, the Client only interacts with the
   Printer using one of its URIs.  This duality is not needed for Job
   objects, since Printers will act as the "factory" for Job objects and
   a given Printer will, depending on the Printer's security
   configuration, generate the correct URI for new Job objects.

9.3.  URIs for Each Authentication Mechanism

   Each URI has an authentication mechanism associated with it.  If the
   URI is the "i-th" element of "printer-uri-supported", then the
   authentication mechanism is the "i-th" element of
   "uri-authentication-supported".  For a list of possible
   authentication mechanisms, see Section 5.4.2.

   The Printer uses an authentication mechanism to determine the name of
   the user performing an operation.  This user is called the
   "authenticated user".  The credibility of authentication depends on
   the mechanism that the Printer uses to obtain the user's name.  When
   the authentication mechanism is 'none', all authenticated users are
   'anonymous'.

   During Job Creation requests, the Printer initializes the value of
   the "job-originating-user-name" attribute (see Section 5.3.6) to be
   the authenticated user.  The authenticated user in this case is
   called the "Job owner".

   If an implementation can be configured to support more than one
   authentication mechanism (see Section 5.4.2), then it MUST implement
   rules for determining equality of authenticated user names that have
   been authenticated via different authentication mechanisms.  One
   possible policy is that identical names that are authenticated via
   different mechanisms are different.  For example, a user can cancel
   his Job only if he uses the same authentication mechanism for both
   Cancel-Job and Print-Job.  Another policy is that identical names
   that are authenticated via different mechanisms are the same if the
   authentication mechanism for the later operation is not less strong
   than the authentication mechanism for the earlier Job Creation
   operation.  For example, a user can cancel his Job only if he uses
   the same or stronger authentication mechanism for Cancel-Job and
   Print-Job.  With this second policy, a Job submitted via



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   'requesting-user-name' authentication could be canceled via 'digest'
   authentication.  With the first policy, the Job could not be canceled
   in this way.

   A Client is able to determine the authentication mechanism used to
   create a Job.  It is the "i-th" value of the Printer's
   "uri-authentication-supported" attribute (see Section 5.4.2),
   where "i" is the index of the element of the Printer's
   "printer-uri-supported" attribute (see Section 5.4.1) equal to the
   Job's "job-printer-uri" attribute (see Section 5.3.3).

9.4.  Restricted Queries

   In many IPP operations, a Client supplies a list of attributes to be
   returned in the response.  For security reasons, an IPP object can be
   configured not to return all attributes (or all values) that a Client
   requests.  The Job attributes returned MAY depend on whether the
   requesting user is the same as the user that submitted the Job.  The
   IPP object MAY even return none of the requested attributes.  In such
   cases, the status returned is the same as if the object had returned
   all requested attributes.  The Client cannot tell by such a response
   whether the requested attribute was present or absent in the object.

9.5.  Operations Performed by Operators and Administrators

   For the three Printer operations Pause-Printer, Resume-Printer, and
   Purge-Jobs (see Sections 4.2.7, 4.2.8, and 4.2.9), the requesting
   user is intended to be an Operator or Administrator of the Printer
   (see Section 1).  Otherwise, the IPP Printer MUST reject the
   operation and return 'client-error-forbidden',
   'client-error-not-authenticated', or 'client-error-not-authorized'
   as appropriate.  For operations on Jobs, the requesting user is
   intended to be the Job owner or can be an Operator or Administrator
   of the Printer.  The means for authorizing an Operator or
   Administrator of the Printer are not specified in this document.

9.6.  Queries on Jobs Submitted Using Non-IPP Protocols

   If the device that an IPP Printer is representing is able to accept
   Jobs using other Job submission protocols in addition to IPP, such an
   implementation SHOULD at least allow such "foreign" Jobs to be
   queried using Get-Jobs returning "job-id" and "job-uri" as 'unknown'.
   Such an implementation MAY support all of the same IPP Job attributes
   as for IPP Jobs.  The IPP object returns the 'unknown' out-of-band
   value for any requested attribute of a foreign Job that is supported
   for IPP Jobs but not for foreign Jobs.





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   IPP Printers SHOULD also generate "job-id" and "job-uri" values for
   such foreign Jobs, if possible, so that they can be targets of other
   IPP operations, such as Get-Job-Attributes and Cancel-Job.  Such an
   implementation also needs to deal with the problem of authentication
   of such foreign Jobs.  One approach would be to treat all such
   foreign Jobs as belonging to users other than the user of the IPP
   Client.  Another approach would be for the foreign Job to belong to
   'anonymous' -- then only authenticated Operators or Administrators of
   the IPP Printer could query the foreign Jobs with an IPP request.
   Alternatively, if the security policy is to allow users to query
   other users' Jobs, then the foreign Jobs would also be visible to an
   End User IPP Client using Get-Jobs and Get-Job-Attributes.

10.  Changes since RFC 2911

   The following changes have been made since RFC 2911:

   o  Errata ID 364: Fixed range of "redirection" status-code values (to
      0x03xx).

   o  Errata ID 694: Fixed range of vendor status-code values (0x0n80 to
      0x0nff).

   o  Errata ID 3072: Reworded multiple-document-handling definition,
      since it also applies to Jobs with a single Document and is the
      only interoperable way to request uncollated copies.

   o  Errata ID 3365: Fixed bad 'nameWithLanguage' maximum length by
      referencing the 'nameWithoutLanguage' section (i.e.,
      Section 5.1.3.1).

   o  Errata ID 4173: Fixed range of vendor operation codes (0x4000 to
      0x7fff).

   o  Updated obsoleted RFC references.

   o  Changed the IPP/1.1 Implementor's Guide reference to RFC 3196.

   o  Updated Create-Job, Send-Document, and Send-URI to RECOMMENDED.

   o  Incorporated 'collection' attribute content from RFC 3382.

   o  Obsoleted all attributes and values defined in RFC 3381, as they
      do not interact well with the "finishings" attribute and have
      never been widely implemented.

   o  Deprecated the Purge-Jobs and Restart-Job operations, which
      destroy accounting information.



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   o  Dropped type3 registration procedures.

   o  Changed the vendor attribute and keyword naming recommendations to
      use SMI Private Enterprise Numbers ("smiNNN-foo") instead of
      domain names.

   o  Split READ-ONLY Job Description and Printer Description attributes
      into Job Status and Printer Status attributes to match the current
      IANA IPP registry organization.

   o  Referenced all IETF and PWG IPP standards.

   o  Updated OPTIONAL operations, attributes, and values to RECOMMENDED
      for consistency with IPP 2.0, IPP Everywhere, and the IPP
      Implementor's Guide v2.0.

   o  Removed the appendix on media names.  Readers are directed to
      "PWG Media Standardized Names 2.0 (MSN2)" [PWG5101.1].

11.  References

11.1.  Normative References

   [ASME-Y14.1M]
              ASME Y14.1M-2012, "Metric Drawing Sheet Size and Format",
              March 2013.

   [ISO10175] ISO/IEC 10175, "Information technology -- Text and office
              systems -- Document Printing Application (DPA) -- Part 1:
              Abstract service definition and procedures",
              September 1996.

   [ISO10646] ISO/IEC 10646:2014, JTC1/SC2, "Information technology --
              Universal Coded Character Set (UCS)", September 2014.

   [ISO8859-1]
              ISO/IEC 8859-1:1998, "Information technology -- 8-bit
              single-byte coded graphic character sets -- Part 1: Latin
              alphabet No. 1", April 1998.

   [PWG5100.1]
              Sweet, M., "IPP Finishings 2.0 (FIN)", December 2014,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippfinishings20-20141219-5100.1.pdf>.







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   [PWG5100.11]
              Hastings, T. and D. Fullman, "Internet Printing Protocol
              (IPP): Job and Printer Extensions -- Set 2 (JPS2)",
              October 2010, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippjobprinterext10-20101030-5100.11.pdf>.

   [PWG5100.12]
              Sweet, M. and I. McDonald, "IPP Version 2.0, 2.1, and
              2.2", October 2015, <http://ftp.pwg.org/pub/pwg/standards/
              std-ipp20-20151030-5100.12.pdf>.

   [PWG5100.13]
              Sweet, M., McDonald, I., and P. Zehler, "IPP: Job and
              Printer Extensions -- Set 3 (JPS3)", July 2012,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippjobprinterext3v10-20120727-5100.13.pdf>.

   [PWG5100.14]
              Sweet, M., McDonald, I., Mitchell, A., and J. Hutchings,
              "IPP Everywhere", January 2013,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippeve10-20130128-5100.14.pdf>.

   [PWG5100.15]
              Sweet, M., "IPP FaxOut Service", June 2014,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippfaxout10-20140618-5100.15.pdf>.

   [PWG5100.16]
              Sweet, M., "IPP Transaction-Based Printing Extensions",
              November 2013, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ipptrans10-20131108-5100.16.pdf>.

   [PWG5100.17]
              Zehler, P. and M. Sweet, "IPP Scan Service (SCAN)",
              September 2014, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippscan10-20140918-5100.17.pdf>.

   [PWG5100.18]
              Sweet, M. and I. McDonald, "IPP Shared Infrastructure
              Extensions (INFRA)", June 2015,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippinfra10-20150619-5100.18.pdf>.

   [PWG5100.19]
              Kennedy, S., "IPP Implementor's Guide v2.0 (IG)",
              August 2015, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippig20-20150821-5100.19.pdf>.



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   [PWG5100.2]
              Hastings, T. and R. Bergman, "Internet Printing Protocol
              (IPP): "output-bin" attribute extension", February 2001,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippoutputbin10-20010207-5100.2.pdf>.

   [PWG5100.3]
              Ocke, K. and T. Hastings, "Internet Printing Protocol
              (IPP): Production Printing Attributes -- Set1",
              February 2001, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippprodprint10-20010212-5100.3.pdf>.

   [PWG5100.5]
              Carney, D., Hastings, T., and P. Zehler, "Standard for The
              Internet Printing Protocol (IPP): Document Object",
              October 2003, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippdocobject10-20031031-5100.5.pdf>.

   [PWG5100.6]
              Zehler, P., Herriot, R., and K. Ocke, "Standard for The
              Internet Printing Protocol (IPP): Page Overrides",
              October 2003, <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ipppageoverride10-20031031-5100.6.pdf>.

   [PWG5100.7]
              Hastings, T. and P. Zehler, "Standard for The Internet
              Printing Protocol (IPP): Job Extensions", October 2003,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippjobext10-20031031-5100.7.pdf>.

   [PWG5100.8]
              Carney, D. and H. Lewis, "Standard for Internet Printing
              Protocol (IPP): "-actual" attributes", March 2003,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippactuals10-20030313-5100.8.pdf>.

   [PWG5100.9]
              McDonald, I. and C. Whittle, "Internet Printing Protocol
              (IPP): Printer State Extensions v1.0", July 2009,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-ippstate10-20090731-5100.9.pdf>.

   [PWG5101.1]
              Sweet, M., Bergman, R., and T. Hastings, "PWG Media
              Standardized Names 2.0 (MSN2)", March 2013,
              <http://ftp.pwg.org/pub/pwg/candidates/
              cs-pwgmsn20-20130328-5101.1.pdf>.




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   [RFC20]    Cerf, V., "ASCII format for network interchange", STD 80,
              RFC 20, DOI 10.17487/RFC0020, October 1969,
              <http://www.rfc-editor.org/info/rfc20>.

   [RFC793]   Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <http://www.rfc-editor.org/info/rfc793>.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <http://www.rfc-editor.org/info/rfc1035>.

   [RFC1951]  Deutsch, P., "DEFLATE Compressed Data Format Specification
              version 1.3", RFC 1951, DOI 10.17487/RFC1951, May 1996,
              <http://www.rfc-editor.org/info/rfc1951>.

   [RFC1952]  Deutsch, P., "GZIP file format specification version 4.3",
              RFC 1952, DOI 10.17487/RFC1952, May 1996,
              <http://www.rfc-editor.org/info/rfc1952>.

   [RFC1977]  Schryver, V., "PPP BSD Compression Protocol", RFC 1977,
              DOI 10.17487/RFC1977, August 1996,
              <http://www.rfc-editor.org/info/rfc1977>.

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              DOI 10.17487/RFC2046, November 1996,
              <http://www.rfc-editor.org/info/rfc2046>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
              DOI 10.17487/RFC2818, May 2000,
              <http://www.rfc-editor.org/info/rfc2818>.

   [RFC3196]  Hastings, T., Manros, C., Zehler, P., Kugler, C., and H.
              Holst, "Internet Printing Protocol/1.1: Implementor's
              Guide", RFC 3196, DOI 10.17487/RFC3196, November 2001,
              <http://www.rfc-editor.org/info/rfc3196>.

   [RFC3380]  Hastings, T., Herriot, R., Kugler, C., and H. Lewis,
              "Internet Printing Protocol (IPP): Job and Printer Set
              Operations", RFC 3380, DOI 10.17487/RFC3380,
              September 2002, <http://www.rfc-editor.org/info/rfc3380>.




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   [RFC3510]  Herriot, R. and I. McDonald, "Internet Printing
              Protocol/1.1: IPP URL Scheme", RFC 3510,
              DOI 10.17487/RFC3510, April 2003,
              <http://www.rfc-editor.org/info/rfc3510>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of
              ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629,
              November 2003, <http://www.rfc-editor.org/info/rfc3629>.

   [RFC3805]  Bergman, R., Lewis, H., and I. McDonald, "Printer MIB v2",
              RFC 3805, DOI 10.17487/RFC3805, June 2004,
              <http://www.rfc-editor.org/info/rfc3805>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <http://www.rfc-editor.org/info/rfc3986>.

   [RFC3995]  Herriot, R. and T. Hastings, "Internet Printing Protocol
              (IPP): Event Notifications and Subscriptions", RFC 3995,
              DOI 10.17487/RFC3995, March 2005,
              <http://www.rfc-editor.org/info/rfc3995>.

   [RFC3996]  Herriot, R., Hastings, T., and H. Lewis, "Internet
              Printing Protocol (IPP): The 'ippget' Delivery Method for
              Event Notifications", RFC 3996, DOI 10.17487/RFC3996,
              March 2005, <http://www.rfc-editor.org/info/rfc3996>.

   [RFC3998]  Kugler, C., Lewis, H., and T. Hastings, Ed., "Internet
              Printing Protocol (IPP): Job and Printer Administrative
              Operations", RFC 3998, DOI 10.17487/RFC3998, March 2005,
              <http://www.rfc-editor.org/info/rfc3998>.

   [RFC5051]  Crispin, M., "i;unicode-casemap - Simple Unicode Collation
              Algorithm", RFC 5051, DOI 10.17487/RFC5051, October 2007,
              <http://www.rfc-editor.org/info/rfc5051>.

   [RFC5234]  Crocker, D., Ed., and P. Overell, "Augmented BNF for
              Syntax Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <http://www.rfc-editor.org/info/rfc5234>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <http://www.rfc-editor.org/info/rfc5246>.





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   [RFC5646]  Phillips, A., Ed., and M. Davis, Ed., "Tags for
              Identifying Languages", BCP 47, RFC 5646,
              DOI 10.17487/RFC5646, September 2009,
              <http://www.rfc-editor.org/info/rfc5646>.

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, DOI 10.17487/RFC6838, January 2013,
              <http://www.rfc-editor.org/info/rfc6838>.

   [RFC7230]  Fielding, R., Ed., and J. Reschke, Ed., "Hypertext
              Transfer Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <http://www.rfc-editor.org/info/rfc7230>.

   [RFC7472]  McDonald, I. and M. Sweet, "Internet Printing Protocol
              (IPP) over HTTPS Transport Binding and the 'ipps' URI
              Scheme", RFC 7472, DOI 10.17487/RFC7472, March 2015,
              <http://www.rfc-editor.org/info/rfc7472>.

   [RFC7612]  Fleming, P. and I. McDonald, "Lightweight Directory Access
              Protocol (LDAP): Schema for Printer Services", RFC 7612,
              DOI 10.17487/RFC7612, June 2015,
              <http://www.rfc-editor.org/info/rfc7612>.

   [RFC7616]  Shekh-Yusef, R., Ed., Ahrens, D., and S. Bremer, "HTTP
              Digest Access Authentication", RFC 7616,
              DOI 10.17487/RFC7616, September 2015,
              <http://www.rfc-editor.org/info/rfc7616>.

   [RFC7617]  Reschke, J., "The 'Basic' HTTP Authentication Scheme",
              RFC 7617, DOI 10.17487/RFC7617, September 2015,
              <http://www.rfc-editor.org/info/rfc7617>.

   [RFC8010]  Sweet, M. and I. McDonald, "Internet Printing
              Protocol/1.1: Encoding and Transport", RFC 8010,
              DOI 10.17487/RFC8010, January 2017,
              <http://www.rfc-editor.org/info/rfc8010>.













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11.2.  Informative References

   [HTPP]     Barnett, J., Carter, K., and R. deBry, "Internet Print
              Protocol Proposal: HTPP -- Hypertext Print Protocol
              (HTPP/1.0 Initial Draft)", October 1996,
              <ftp://ftp.pwg.org/pub/pwg/ipp/historic/htpp/
              overview.ps.gz>.

   [IANA-CS]  IANA, "Registry of Coded Character Sets",
              <http://www.iana.org/assignments/character-sets/>.

   [IANA-MT]  IANA, "Media Types",
              <http://www.iana.org/assignments/media-types/>.

   [IANA-PEN]
              IANA, "Private Enterprise Numbers",
              <http://www.iana.org/assignments/enterprise-numbers/>.

   [ISO32000] "Document management -- Portable document format --
              Part 1: PDF 1.7", July 2008, <http://www.adobe.com/
              devnet/acrobat/pdfs/PDF32000_2008.pdf>.

   [LDPA]     Isaacson, S., Taylor, D., MacKay, M., Zehler, P.,
              Hastings, T., and C. Manros, "LDPA - Lightweight Document
              Printing Application", Proposed Internet-Draft,
              October 1996, <ftp://ftp.pwg.org/pub/pwg/ipp/
              historic/ldpa/ldpa8.pdf.gz>.

   [P1387.4]  Kirk, M., "POSIX Systems Administration - Part 4: Printing
              Interfaces, POSIX 1387.4 D8", 1998.

   [PSIS]     Herriot, R., Ed., "X/Open: A Printing System
              Interoperability Specification (PSIS)", August 1995.

   [PWG-IPP-WG]
              IEEE-ISTO Printer Working Group, "Internet Printing
              Protocol Workgroup", <http://www.pwg.org/ipp>.

   [RFC959]   Postel, J. and J. Reynolds, "File Transfer Protocol",
              STD 9, RFC 959, DOI 10.17487/RFC0959, October 1985,
              <http://www.rfc-editor.org/info/rfc959>.

   [RFC1179]  McLaughlin, L., "Line printer daemon protocol", RFC 1179,
              DOI 10.17487/RFC1179, August 1990,
              <http://www.rfc-editor.org/info/rfc1179>.






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   [RFC1738]  Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
              Resource Locators (URL)", RFC 1738, DOI 10.17487/RFC1738,
              December 1994, <http://www.rfc-editor.org/info/rfc1738>.

   [RFC2565]  Herriot, R., Ed., Butler, S., Moore, P., and R. Turner,
              "Internet Printing Protocol/1.0: Encoding and Transport",
              RFC 2565, DOI 10.17487/RFC2565, April 1999,
              <http://www.rfc-editor.org/info/rfc2565>.

   [RFC2566]  deBry, R., Hastings, T., Herriot, R., Isaacson, S., and P.
              Powell, "Internet Printing Protocol/1.0: Model and
              Semantics", RFC 2566, DOI 10.17487/RFC2566, April 1999,
              <http://www.rfc-editor.org/info/rfc2566>.

   [RFC2567]  Wright, F., "Design Goals for an Internet Printing
              Protocol", RFC 2567, DOI 10.17487/RFC2567, April 1999,
              <http://www.rfc-editor.org/info/rfc2567>.

   [RFC2568]  Zilles, S., "Rationale for the Structure of the Model and
              Protocol for the Internet Printing Protocol", RFC 2568,
              DOI 10.17487/RFC2568, April 1999,
              <http://www.rfc-editor.org/info/rfc2568>.

   [RFC2569]  Herriot, R., Ed., Hastings, T., Jacobs, N., and J. Martin,
              "Mapping between LPD and IPP Protocols", RFC 2569,
              DOI 10.17487/RFC2569, April 1999,
              <http://www.rfc-editor.org/info/rfc2569>.

   [RFC2579]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Textual Conventions for SMIv2",
              STD 58, RFC 2579, DOI 10.17487/RFC2579, April 1999,
              <http://www.rfc-editor.org/info/rfc2579>.

   [RFC2978]  Freed, N. and J. Postel, "IANA Charset Registration
              Procedures", BCP 19, RFC 2978, DOI 10.17487/RFC2978,
              October 2000, <http://www.rfc-editor.org/info/rfc2978>.

   [RFC3239]  Kugler, C., Lewis, H., and T. Hastings, "Internet Printing
              Protocol (IPP): Requirements for Job, Printer, and Device
              Administrative Operations", RFC 3239,
              DOI 10.17487/RFC3239, February 2002,
              <http://www.rfc-editor.org/info/rfc3239>.

   [RFC3997]  Hastings, T., Ed., deBry, R., and H. Lewis, "Internet
              Printing Protocol (IPP): Requirements for IPP
              Notifications", RFC 3997, DOI 10.17487/RFC3997,
              March 2005, <http://www.rfc-editor.org/info/rfc3997>.




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   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,
              DOI 10.17487/RFC4122, July 2005,
              <http://www.rfc-editor.org/info/rfc4122>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <http://www.rfc-editor.org/info/rfc5226>.

   [RFC6068]  Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto'
              URI Scheme", RFC 6068, DOI 10.17487/RFC6068, October 2010,
              <http://www.rfc-editor.org/info/rfc6068>.

   [RFC7525]  Sheffer, Y., Holz, R., and P. Saint-Andre,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525,
              May 2015, <http://www.rfc-editor.org/info/rfc7525>.

   [SWP]      Moore, P. and S. Butler, "Simple Web Printing (SWP/1.0)",
              May 1997, <ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/
              swp9705.pdf>.




























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Appendix A.  Formats for IPP Registration Proposals

   In order to propose an IPP extension for registration, the proposer
   must submit an application to IANA by email to "iana@iana.org" or by
   filling out the appropriate form on the IANA web pages
   (http://www.iana.org).  This section specifies the required
   information and the formats for proposing registrations of extensions
   to IPP as provided in Section 7 for:

   1.  attributes

   2.  type2 'keyword' attribute values

   3.  type2 'enum' attribute values

   4.  operations

   5.  status-code values

A.1.  Attribute Registration

   Type of registration: attribute

   Proposed keyword name of this attribute:

   Types of attributes (Document Description, Document Status, Document
   Template, Event Notifications, Job Description, Job Status, Job
   Template, Operation, Printer Description, Printer Status,
   Subscription Description, Subscription Status, Subscription
   Template):

   Operations to be used if the attribute is an operation attribute:

   Object (Document, Job, Printer, Subscription, etc. if bound to an
   object):

   Attribute syntax(es) (include '1setOf' and range; see Section 5.2):

   If attribute syntax is 'keyword' or 'enum', is it type1 or type2?

   If this is a Printer attribute, MAY the value returned depend on
   "document-format"?  (See Section 7.2.)

   If this is a Job Template attribute, how does its specification
   depend on the value of the "multiple-document-handling" attribute?






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   Specification of this attribute (follow the style of Section 5.2):

   Name of proposer:

   Email address of proposer:

   Note: For attributes, the IPP Designated Expert will be the point of
   contact and change controller for the approved registration
   specification, if any maintenance of the registration specification
   is needed.

A.2.  type2 'keyword' Attribute Value Registration

   Type of registration: type2 keyword attribute value

   Name of attribute to which this keyword specification is to be added:

   Proposed keyword name of this 'keyword' value:

   Specification of this 'keyword' value (follow the style of
   Section 5.1.4):

   Name of proposer:

   Email address of proposer:

   Note: For type2 keywords, the Designated Expert will be the point of
   contact and change controller for the approved registration
   specification, if any maintenance of the registration specification
   is needed.

A.3.  type2 'enum' Attribute Value Registration

   Type of registration: type2 enum attribute value

   Name of attribute to which this enum specification is to be added:

   Keyword symbolic name of this enum value:

   Numeric value (to be assigned by the IPP Designated Expert in
   consultation with IANA):

   Specification of this enum value (follow the style of Section 5.1.5):

   Name of proposer:

   Email address of proposer:




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   Note: For type2 enums, the Designated Expert will be the point of
   contact and change controller for the approved registration
   specification, if any maintenance of the registration specification
   is needed.

A.4.  Operation Registration

   Type of registration: operation

   Proposed name of this operation:

   Numeric "operation-id" value according to Section 5.4.15 (to be
   assigned by the IPP Designated Expert in consultation with IANA):

   Object Target (Document, Job, Printer, Subscription, etc. that
   operation is upon):

   Specification of this operation (follow the style of Section 4):

   Name of proposer:

   Email address of proposer:

   Note: For operations, the IPP Designated Expert will be the point of
   contact and change controller for the approved registration
   specification, if any maintenance of the registration specification
   is needed.

A.5.  Status-Code Registration

   Type of registration: status-code

   Keyword symbolic name of this status-code value:

   Numeric value (to be assigned by the IPP Designated Expert in
   consultation with IANA):

   Operations that this status-code can be used with:

   Specification of this status-code (follow the style of Appendix B):

   Name of proposer:

   Email address of proposer:







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   Note: For status-code values, the Designated Expert will be the point
   of contact and change controller for the approved registration
   specification, if any maintenance of the registration specification
   is needed.

Appendix B.  Status-Code Values and Suggested Status-Code Messages

   This section defines status-code enum keywords and values that are
   used to provide semantic information on the results of an operation
   request.  Each operation response MUST include a status-code.  The
   response MAY also contain a status message that provides a short
   textual description of the status.  The status-code is intended for
   use by automata, and the status message is intended for the human
   End User.

   The prefix of the status keyword defines the class of response as
   follows:

   "informational" - Request received, continuing process

   "successful" - The action was successfully received, understood, and
   accepted

   "redirection" - Further action is taken in order to complete the
   request

   "client-error" - The request contains bad syntax or cannot be
   fulfilled

   "server-error" - The IPP object failed to fulfill an apparently valid
   request

   As with type2 enums, IPP status-code values are extensible.
   Regardless of whether all status-code values are recognized, IPP
   Clients MUST understand the class of any status-code, as indicated by
   the prefix, and treat any unrecognized response as being equivalent
   to the first status-code of that class, with the exception that an
   unrecognized response MUST NOT be cached.  For example, if an
   unrecognized status-code of 'client-error-xxx-yyy' is received by the
   Client, it can safely assume that there was something wrong with its
   request and treat the response as if it had received a
   'client-error-bad-request' status-code.  The name of the enum is the
   suggested status message for US English.

   See [PWG5100.19] for guidelines on presenting status messages to
   End Users.





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   The status-code values range from 0x0000 to 0x7fff.  The value ranges
   for each status-code class are as follows:

   "successful" - 0x0000 to 0x00ff

   "informational" - 0x0100 to 0x01ff

   "redirection" - 0x0300 to 0x03ff

   "client-error" - 0x0400 to 0x04ff

   "server-error" - 0x0500 to 0x05ff

   The top half (128 values) of each range (0x0n80 to 0x0nff, for n = 0
   to 5) is reserved for vendor use within each status-code class.
   Values 0x0600 to 0x7fff are reserved for future assignment by
   Standards Track documents and MUST NOT be used.

B.1.  Status-Code Values

   Each status-code is described below.  Appendix B.2 contains a table
   that indicates which status-code values apply to which operations.
   The Implementor's Guides [RFC3196] [PWG5100.19] provide guidance for
   processing IPP attributes for all operations, including status-code
   values.

B.1.1.  Informational

   This class of status-code values indicates a provisional response and
   is to be used for informational purposes only.

   There are no values defined in this document for this class of
   status-code values.

B.1.2.  Successful Status-Code Values

   This class of status-code values indicates that the Client's request
   was successfully received, understood, and accepted.

B.1.2.1.  successful-ok (0x0000)

   The request has succeeded, and no request attributes were substituted
   or ignored.  In the case of a response to a Job Creation request, the
   'successful-ok' status-code indicates that the request was
   successfully received and validated, and that the Job object has been
   created; it does not indicate that the Job has been processed.  The
   transition of the Job object into the 'completed' state is the only
   indicator that the Job has been printed.



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B.1.2.2.  successful-ok-ignored-or-substituted-attributes (0x0001)

   The request has succeeded, but some supplied (1) attributes were
   ignored or (2) unsupported values were substituted with supported
   values or were ignored in order to perform the operation without
   rejecting it.  Unsupported attributes, attribute syntaxes, or values
   MUST be returned in the Unsupported Attributes group of the response
   for all operations.  There is an exception to this rule for the query
   operations Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes
   for the "requested-attributes" operation attribute only.  When the
   supplied values of the "requested-attributes" operation attribute are
   requesting attributes that are not supported, the IPP object SHOULD
   return the "requested-attributes" operation attribute in the
   Unsupported Attributes group of the response (with the unsupported
   values only).  See Sections 4.1.7 and 4.2.1.2.

B.1.2.3.  successful-ok-conflicting-attributes (0x0002)

   The request has succeeded, but some supplied attribute values
   conflicted with the values of other supplied attributes.  Either
   (1) these conflicting values were substituted with (supported) values
   or (2) the attributes were removed in order to process the Job
   without rejecting it.  Attributes or values that conflict with other
   attributes and have been substituted or ignored MUST be returned in
   the Unsupported Attributes group of the response for all operations
   as supplied by the Client.  See Sections 4.1.7 and 4.2.1.2.

B.1.3.  Redirection Status-Code Values

   This class of status-code values indicates that further action needs
   to be taken to fulfill the request.

   There are no values defined in this document for this class of
   status-code values.

B.1.4.  Client Error Status-Code Values

   This class of status-code values is intended for cases in which the
   Client seems to have erred.  The IPP object SHOULD return a message
   containing an explanation of the error situation and whether it is a
   temporary or permanent condition.










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B.1.4.1.  client-error-bad-request (0x0400)

   The request could not be understood by the IPP object due to
   malformed syntax (such as the value of a fixed-length attribute whose
   length does not match the prescribed length for that attribute -- see
   the Implementor's Guides [RFC3196] [PWG5100.19]).  The IPP
   application SHOULD NOT repeat the request without modifications.

B.1.4.2.  client-error-forbidden (0x0401)

   The IPP object understood the request but is refusing to fulfill it.
   Additional authentication information or authorization credentials
   will not help, and the request SHOULD NOT be repeated.  This
   status-code is commonly used when the IPP object does not wish to
   reveal exactly why the request has been refused or when no other
   response is applicable.

B.1.4.3.  client-error-not-authenticated (0x0402)

   The request requires user authentication.  The IPP Client can repeat
   the request with suitable authentication information.  If the request
   already included authentication information, then this status-code
   indicates that authorization has been refused for those credentials.
   If this response contains the same challenge as the prior response
   and the user agent has already attempted authentication at least
   once, then the response message can contain relevant diagnostic
   information.  This status-code reveals more information than
   'client-error-forbidden'.

B.1.4.4.  client-error-not-authorized (0x0403)

   The requester is not authorized to perform the request.  Additional
   authentication information or authorization credentials will not
   help, and the request SHOULD NOT be repeated.  This status-code is
   used when the IPP object wishes to reveal that the authentication
   information is understandable; however, the requester is explicitly
   not authorized to perform the request.  This status-code reveals more
   information than 'client-error-forbidden' and
   'client-error-not-authenticated'.

B.1.4.5.  client-error-not-possible (0x0404)

   This status-code is used when the request is for something that
   cannot happen.  For example, there might be a request to cancel a Job
   that has already been canceled or aborted by the system.  The IPP
   Client SHOULD NOT repeat the request.





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B.1.4.6.  client-error-timeout (0x0405)

   The Client did not produce a request within the time that the IPP
   object was prepared to wait.  For example, a Client issued a
   Create-Job operation and then, after a long period of time, issued a
   Send-Document operation; this error status-code was returned in
   response to the Send-Document request (see Section 4.3.1).  The IPP
   object might have been forced to clean up resources that had been
   held for the waiting additional Documents.  The IPP object was forced
   to close the Job, since the Client took too long.  The Client
   SHOULD NOT repeat the request without modifications.

B.1.4.7.  client-error-not-found (0x0406)

   The IPP object has not found anything matching the request URI.  No
   indication is given of whether the condition is temporary or
   permanent.  For example, a Client with an old reference to a Job
   (a URI) tries to cancel the Job; however, in the meantime the Job
   might have been completed and all record of it at the Printer has
   been deleted.  This status-code, 'client-error-not-found', is
   returned indicating that the referenced Job cannot be found.  This
   error status-code is also used when a Client supplies a URI as a
   reference to the Document data in either a Print-URI or Send-URI
   operation but the Document cannot be found.

   In practice, an IPP application should avoid a "not found" situation
   by first querying and presenting a list of valid Printer URIs and Job
   URIs to the End User.

B.1.4.8.  client-error-gone (0x0407)

   The requested object is no longer available, and no forwarding
   address is known.  This condition should be considered permanent.
   Clients with link-editing capabilities should delete references to
   the request URI after user approval.  If the IPP object does not know
   or has no facility to determine whether or not the condition is
   permanent, the status-code 'client-error-not-found' should be used
   instead.

   This response is primarily intended to assist the task of maintenance
   by notifying the recipient that the resource is intentionally
   unavailable and that the IPP object Administrator desires that remote
   links to that resource be removed.  It is not necessary to mark all
   permanently unavailable resources as "gone" or to keep the mark for
   any length of time -- that is left to the discretion of the IPP
   object Administrator and/or Printer implementation.





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B.1.4.9.  client-error-request-entity-too-large (0x0408)

   The IPP object is refusing to process a request because the request
   entity is larger than the IPP object is willing or able to process.
   An IPP Printer returns this status-code when it limits the size of
   Print Jobs and it receives a Print Job that exceeds that limit or
   when the attributes are so many that their encoding causes the
   request entity to exceed IPP object capacity.

B.1.4.10.  client-error-request-value-too-long (0x0409)

   The IPP object is refusing to service the request because one or more
   of the Client-supplied attributes have a variable-length value that
   is longer than the maximum length specified for that attribute.  The
   IPP object might not have sufficient resources (memory, buffers,
   etc.) to process (even temporarily), interpret, and/or ignore a value
   larger than the maximum length.  Another use of this error code is
   when the IPP object supports the processing of a large value that is
   less than the maximum length, but during the processing of the
   request as a whole, the object can pass the value onto some other
   system component that is not able to accept the large value.  For
   more details, see the Implementor's Guides [RFC3196] [PWG5100.19].

   Note: For attribute values that are URIs, this rare condition is only
   likely to occur when a Client has improperly submitted a request with
   long query information (e.g., an IPP application allows an End User
   to enter an invalid URI), when the Client has descended into a URI
   "black hole" of redirection (e.g., a redirected URI prefix that
   points to a suffix of itself), or when the IPP object is under attack
   by a Client attempting to exploit security holes present in some IPP
   objects using fixed-length buffers for reading or manipulating the
   request URI.

B.1.4.11.  client-error-document-format-not-supported (0x040a)

   The IPP object is refusing to service the request because the
   Document data is in a format, as specified in the "document-format"
   operation attribute, that is not supported by the Printer.  This
   error is returned independent of the Client-supplied
   "ipp-attribute-fidelity" attribute.  The Printer MUST return this
   status-code, even if there are other Job Template attributes that are
   not supported as well, since this error is a bigger problem than with
   Job Template attributes.  See Sections 4.1.6.1, 4.1.7, and 4.2.1.1.








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B.1.4.12.  client-error-attributes-or-values-not-supported (0x040b)

   In a Job Creation request, if the Printer does not support one or
   more attributes, attribute syntaxes, or attribute values supplied in
   the request and the Client supplied the "ipp-attribute-fidelity"
   operation attribute with the 'true' value, the Printer MUST return
   this status-code.  The Printer MUST also return in the Unsupported
   Attributes group all the attributes and/or values supplied by the
   Client that are not supported.  See Section 4.1.7.  Examples would be
   if the request indicates 'iso-a4' media but that media type is not
   supported by the Printer, or if the Client supplies a Job Template
   attribute and the attribute itself is not even supported by the
   Printer.  If the "ipp-attribute-fidelity" attribute is 'false', the
   Printer MUST ignore or substitute values for unsupported Job Template
   attributes and values rather than reject the request and return this
   status-code.

   For any operation where a Client requests attributes (such as a
   Get-Jobs, Get-Printer-Attributes, or Get-Job-Attributes operation),
   if the IPP object does not support one or more of the requested
   attributes, the IPP object simply ignores the unsupported requested
   attributes and processes the request as if they had not been
   supplied, rather than returning this status-code.  In this case,
   the IPP object MUST return the
   'successful-ok-ignored-or-substituted-attributes' status-code and
   SHOULD return the unsupported attributes as values of the
   "requested-attributes" operation attribute in the Unsupported
   Attributes group (see Appendix B.1.2.2).

B.1.4.13.  client-error-uri-scheme-not-supported (0x040c)

   The scheme of the Client-supplied URI in a Print-URI or a Send-URI
   operation is not supported.  See Sections 4.1.6.1 and 4.1.7.

B.1.4.14.  client-error-charset-not-supported (0x040d)

   For any operation, if the IPP Printer does not support the charset
   supplied by the Client in the "attributes-charset" operation
   attribute, the Printer MUST reject the operation and return this
   status-code, and any 'text' or 'name' attributes using the 'utf-8'
   charset (Section 4.1.4.1).  See Sections 4.1.6.1 and 4.1.7.










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B.1.4.15.  client-error-conflicting-attributes (0x040e)

   The request is rejected because some attribute values conflicted with
   the values of other attributes that this document does not permit to
   be substituted or ignored.  The Printer MUST also return in the
   Unsupported Attributes group the conflicting attributes supplied by
   the Client.  See Sections 4.1.7 and 4.2.1.2.

B.1.4.16.  client-error-compression-not-supported (0x040f)

   The IPP object is refusing to service the request because the
   Document data, as specified in the "compression" operation attribute,
   is compressed in a way that is not supported by the Printer.  This
   error is returned independent of the Client-supplied
   "ipp-attribute-fidelity" attribute.  The Printer MUST return this
   status-code, even if there are other Job Template attributes that are
   not supported as well, since this error is a bigger problem than with
   Job Template attributes.  See Sections 4.1.6.1, 4.1.7, and 4.2.1.1.

B.1.4.17.  client-error-compression-error (0x0410)

   The IPP object is refusing to service the request because the
   Document data cannot be decompressed when using the algorithm
   specified by the "compression" operation attribute.  This error is
   returned independent of the Client-supplied "ipp-attribute-fidelity"
   attribute.  The Printer MUST return this status-code, even if there
   are Job Template attributes that are not supported as well, since
   this error is a bigger problem than with Job Template attributes.
   See Sections 4.1.7 and 4.2.1.1.

B.1.4.18.  client-error-document-format-error (0x0411)

   The IPP object is refusing to service the request because the Printer
   encountered an error in the Document data while interpreting it.
   This error is returned independent of the Client-supplied
   "ipp-attribute-fidelity" attribute.  The Printer MUST return this
   status-code, even if there are Job Template attributes that are not
   supported as well, since this error is a bigger problem than with Job
   Template attributes.  See Sections 4.1.7 and 4.2.1.1.

B.1.4.19.  client-error-document-access-error (0x0412)

   The IPP object is refusing to service the Print-URI or Send-URI
   request because the Printer encountered an access error while
   attempting to validate the accessibility of, or access to, the
   Document data specified in the "document-uri" operation attribute.
   The Printer MAY also return a specific Document access error code
   using the "document-access-error" operation attribute (see



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   Section 4.1.6.4).  This error is returned independent of the
   Client-supplied "ipp-attribute-fidelity" attribute.  The Printer MUST
   return this status-code, even if there are Job Template attributes
   that are not supported as well, since this error is a bigger problem
   than with Job Template attributes.  See Sections 4.1.6.1 and 4.1.7.

B.1.5.  Server Error Status-Code Values

   This class of status-code values indicates cases in which the IPP
   object is aware that it has erred or is incapable of performing the
   request.  The IPP object SHOULD include a message containing an
   explanation of the error situation, and whether it is a temporary or
   permanent condition.

B.1.5.1.  server-error-internal-error (0x0500)

   The IPP object encountered an unexpected condition that prevented it
   from fulfilling the request.  This error status-code differs from
   'server-error-temporary-error' in that it implies a more permanent
   type of internal error.  It also differs from
   'server-error-device-error' in that it implies an unexpected
   condition (unlike a paper-jam or out-of-toner problem, which is
   undesirable but expected).  This error status-code indicates that
   intervention by a knowledgeable human is probably required.

B.1.5.2.  server-error-operation-not-supported (0x0501)

   The IPP object does not support the functionality required to fulfill
   the request.  This is the appropriate response when the IPP object
   does not recognize an operation or is not capable of supporting it.
   See Sections 4.1.6.1 and 4.1.7.

B.1.5.3.  server-error-service-unavailable (0x0502)

   The IPP object is currently unable to handle the request due to
   temporary overloading or due to maintenance of the IPP object.  The
   implication is that this is a temporary condition that will be
   alleviated after some delay.  If known, the length of the delay can
   be indicated in the message.  If no delay is given, the IPP
   application should handle the response as it would for a
   'server-error-temporary-error' response.  If the condition is more
   permanent, the 'client-error-gone' or 'client-error-not-found' error
   status-code could be used.








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B.1.5.4.  server-error-version-not-supported (0x0503)

   The IPP object does not support or refuses to support the IPP version
   that was supplied as the value of the "version-number" operation
   parameter in the request.  The IPP object is indicating that it is
   unable or unwilling to complete the request using the same major and
   minor version number as supplied in the request, other than with this
   error message.  The error response SHOULD contain a "status-message"
   attribute (see Section 4.1.6.2) describing why that version is not
   supported and what other versions are supported by that IPP object.
   See Sections 4.1.6.1, 4.1.7, and 4.1.8.

   The error response MUST identify in the "version-number" operation
   parameter the closest version number that the IPP object does
   support.  For example, if a Client supplies version '1.0' and an
   IPP/1.1 object supports version '1.0', then it responds with
   version '1.0' in all responses to such a request.  If the IPP/1.1
   object does not support version '1.0', then it should accept the
   request and respond with version '1.1' or can reject the request and
   respond with this error code and version '1.1'.  If a Client supplies
   version '1.2', the IPP/1.1 object should accept the request and
   return version '1.1' or can reject the request and respond with this
   error code and version '1.1'.  See Sections 4.1.8 and 5.3.14.

B.1.5.5.  server-error-device-error (0x0504)

   A Printer error, such as a paper jam, occurs while the IPP object
   processes a Print or send operation.  The response contains the true
   Job status (the values of the "job-state" and "job-state-reasons"
   attributes).  Additional information can be returned in the OPTIONAL
   "job-state-message" attribute value or in the OPTIONAL status message
   that describes the error in more detail.  This error status-code is
   only returned in situations where the Printer is unable to accept the
   Job Creation request because of such a device error.  For example, if
   the Printer is unable to spool and can only accept one Job at a time,
   the reason it might reject a Job Creation request is that the Printer
   currently has a paper jam.  In many cases, however, where the Printer
   can accept the request even though the Printer has some error
   condition, the 'successful-ok' status-code will be returned.  In such
   a case, the Client would look at the returned Job object attributes
   or later query the Printer to determine its state and state reasons.










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B.1.5.6.  server-error-temporary-error (0x0505)

   A temporary error such as a buffer-full write error, a memory
   overflow (i.e., the Document data exceeds the memory of the Printer),
   or a disk-full condition, occurs while the IPP Printer processes an
   operation.  The Client MAY try the unmodified request again at some
   later point in time with an expectation that the temporary internal
   error condition has been cleared.  Alternatively, as an
   implementation option, a Printer MAY delay the response until the
   temporary condition is cleared so that no error is returned.

B.1.5.7.  server-error-not-accepting-jobs (0x0506)

   This is a temporary error indicating that the Printer is not
   currently accepting Jobs because the Administrator has set the value
   of the Printer's "printer-is-accepting-jobs" attribute to 'false' (by
   means outside the scope of this IPP/1.1 document).

B.1.5.8.  server-error-busy (0x0507)

   This is a temporary error indicating that the Printer is too busy
   processing Jobs and/or other requests.  The Client SHOULD try the
   unmodified request again at some later point in time with an
   expectation that the temporary busy condition will have been cleared.

B.1.5.9.  server-error-job-canceled (0x0508)

   This is an error indicating that the Job has been canceled by an
   Operator or the system while the Client was transmitting the data to
   the IPP Printer.  If a "job-id" attribute and a "job-uri" attribute
   had been created, then they are returned in the Print-Job,
   Send-Document, or Send-URI response as usual; otherwise, no "job-id"
   and "job-uri" attributes are returned in the response.

B.1.5.10.  server-error-multiple-document-jobs-not-supported (0x0509)

   The IPP object does not support multiple Documents per Job, and a
   Client attempted to supply Document data with a second Send-Document
   or Send-URI operation.












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B.2.  Status-Code Values for IPP Operations

   PJ = Print-Job, PU = Print-URI, CJ = Create-Job, SD = Send-Document,
   SU = Send-URI, V = Validate-Job, GA = Get-Job-Attributes and
   Get-Printer-Attributes, GJ = Get-Jobs, C = Cancel-Job

                                                  IPP Operations
   IPP Status Keyword                       PJ PU CJ SD SU V GA GJ C
   ------------------                       -- -- -- -- -- - -- -- -
   successful-ok                            x  x  x  x  x  x x  x  x
   successful-ok-ignored-or-substituted-    x  x  x  x  x  x x  x  x
        attributes
   successful-ok-conflicting-attributes     x  x  x  x  x  x x  x  x
   client-error-bad-request                 x  x  x  x  x  x x  x  x
   client-error-forbidden                   x  x  x  x  x  x x  x  x
   client-error-not-authenticated           x  x  x  x  x  x x  x  x
   client-error-not-authorized              x  x  x  x  x  x x  x  x
   client-error-not-possible                x  x  x  x  x  x x  x  x
   client-error-timeout                              x  x
   client-error-not-found                   x  x  x  x  x  x x  x  x
   client-error-gone                        x  x  x  x  x  x x  x  x
   client-error-request-entity-too-large    x  x  x  x  x  x x  x  x
   client-error-request-value-too-long      x  x  x  x  x  x x  x  x
   client-error-document-format-not-        x  x     x  x  x x
        supported
   client-error-attributes-or-values-not-   x  x  x  x  x  x x  x  x
        supported
   client-error-uri-scheme-not-supported       x        x
   client-error-charset-not-supported       x  x  x  x  x  x x  x  x
   client-error-conflicting-attributes      x  x  x  x  x  x x  x  x
   client-error-compression-not-supported   x  x     x  x  x
   client-error-compression-error           x  x     x  x
   client-error-document-format-error       x  x     x  x
   client-error-document-access-error          x        x
   server-error-internal-error              x  x  x  x  x  x x  x  x
   server-error-operation-not-supported        x  x  x  x
   server-error-service-unavailable         x  x  x  x  x  x x  x  x
   server-error-version-not-supported       x  x  x  x  x  x x  x  x
   server-error-device-error                x  x  x  x  x
   server-error-temporary-error             x  x  x  x  x
   server-error-not-accepting-jobs          x  x  x        x
   server-error-busy                        x  x  x  x  x  x x  x  x
   server-error-job-canceled                x        x  x
   server-error-multiple-document-jobs-              x  x
          not-supported






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   HJ = Hold-Job, RJ = Release-Job, RS = Restart-Job,
   PP = Pause-Printer, RP = Resume-Printer, PJ = Purge-Jobs

                                            IPP Operations (cont.)
   IPP Status Keyword                       HJ RJ RS PP RP PJ
   ------------------                       -- -- -- -- -- --
   successful-ok                            x  x  x  x  x  x
   successful-ok-ignored-or-substituted-    x  x  x  x  x  x
        attributes
   successful-ok-conflicting-attributes     x  x  x  x  x  x
   client-error-bad-request                 x  x  x  x  x  x
   client-error-forbidden                   x  x  x  x  x  x
   client-error-not-authenticated           x  x  x  x  x  x
   client-error-not-authorized              x  x  x  x  x  x
   client-error-not-possible                x  x  x  x  x  x
   client-error-timeout
   client-error-not-found                   x  x  x  x  x  x
   client-error-gone                        x  x  x  x  x  x
   client-error-request-entity-too-large    x  x  x  x  x  x
   client-error-request-value-too-long      x  x  x  x  x  x
   client-error-document-format-not-
        supported
   client-error-attributes-or-values-not-   x  x  x  x  x  x
        supported
   client-error-uri-scheme-not-supported
   client-error-charset-not-supported       x  x  x  x  x  x
   client-error-conflicting-attributes      x  x  x  x  x  x
   client-error-compression-not-supported
   client-error-compression-error
   client-error-document-format-error
   client-error-document-access-error
   server-error-internal-error              x  x  x  x  x  x
   server-error-operation-not-supported     x  x  x  x  x  x
   server-error-service-unavailable         x  x  x  x  x  x
   server-error-version-not-supported       x  x  x  x  x  x
   server-error-device-error
   server-error-temporary-error             x  x  x  x  x  x
   server-error-not-accepting-jobs
   server-error-busy                        x  x  x  x  x  x
   server-error-job-canceled
   server-error-multiple-document-jobs-
          not-supported









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Appendix C.  Processing IPP Attributes

   When submitting a Print Job to a Printer, the IPP Model allows a
   Client to supply operation and Job Template attributes along with the
   Document data.  These Job Template attributes in the Job Creation
   request affect the rendering, production, and finishing of the
   Documents in the Job.  Similar types of instructions can also be
   contained in the Document data itself.  In addition, the Printer has
   a set of attributes that describe what rendering and finishing
   processes are supported by that Printer.  This model, which allows
   for flexibility and power, also introduces the potential that
   Client-supplied attributes can conflict with either:

   o  what the implementation is capable of realizing (i.e., what the
      Printer supports), or

   o  the instructions embedded within the Document data itself.

   The following sections describe how these two types of conflicts are
   handled in the IPP Model.

C.1.  Fidelity

   If there is a conflict between what the Client requests and what a
   Printer supports, the Client can request one of two possible
   conflict-handling mechanisms:

   1)  either reject the Job, since the Job cannot be processed exactly
       as specified, or

   2)  allow the Printer to make any changes necessary to proceed with
       processing the Job the best it can.

   In the first case, the Client is indicating the following to the
   Printer: "Print the Job exactly as specified with no exceptions, and
   if that can't be done, don't even bother printing the Job at all."
   In the second case, the Client is indicating the following to the
   Printer: "It is more important to make sure the Job is printed rather
   than be processed exactly as specified; just make sure the Job is
   printed even if some Client-supplied attributes need to be changed or
   ignored."

   The IPP Model accounts for this situation by introducing an
   "ipp-attribute-fidelity" attribute.







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   In a Job Creation request, "ipp-attribute-fidelity" is a boolean
   operation attribute that MAY be supplied by the Client.  The value
   'true' indicates that total fidelity to Client-supplied Job Template
   attributes and values is required.  The Client is requesting that the
   Job be printed exactly as specified, and if that is not possible,
   then the Job MUST be rejected rather than processed incorrectly.  The
   value 'false' indicates that a reasonable attempt to print the Job is
   acceptable.  If a Printer does not support some of the
   Client-supplied Job Template attributes or values, the Printer MUST
   ignore or replace them with supported values.  The Printer can choose
   to substitute the default value associated with that attribute or use
   some other supported value that is similar to the unsupported
   requested value.  For example, if a Client supplies a "media" value
   of 'na_letter_8.5x11in', the Printer can choose to substitute
   'iso_a4_210x297mm' rather than a default value of
   'na_personal_3.625x6.5in'.  If the Client does not supply the
   "ipp-attribute-fidelity" attribute, the Printer assumes a value of
   'false'.

   Each Printer implementation MUST support both types of "fidelity"
   printing (that is, whether the Client supplies a value of 'true' or
   'false'):

   o  If the Client supplies 'false' or does not supply the attribute,
      the Printer MUST always accept the request by ignoring unsupported
      Job Template attributes and by substituting unsupported values of
      supported Job Template attributes with supported values.

   o  If the Client supplies 'true', the Printer MUST reject the request
      if the Client supplies unsupported Job Template attributes.

   Since a Client can always query a Printer to find out exactly what is
   and is not supported, "ipp-attribute-fidelity" set to 'false' is
   useful when:

   1)  The End User uses a command line interface to request attributes
       that might not be supported.

   2)  In a GUI context, if the End User expects the Job might be moved
       to another Printer and prefers a suboptimal result to nothing
       at all.

   3)  The End User just wants something reasonable in lieu of nothing
       at all.







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C.2.  Page Description Language (PDL) Override

   If there is a conflict between the value of an IPP Job Template
   attribute and a corresponding instruction in the Document data, the
   value of the IPP attribute SHOULD take precedence over the Document
   instruction.  Consider the case where a previously formatted file of
   Document data is sent to an IPP Printer.  In this case, if the Client
   supplies any attributes at Job submission time, the Client desires
   that those attributes override the embedded instructions.  Consider
   the case where a previously formatted Document has embedded in it
   commands to load 'iso-a4' media.  However, the Document is passed to
   an End User that only has access to a Printer with 'na-letter' media
   loaded.  That End User most likely wants to submit that Document to
   an IPP Printer with the "media" Job Template attribute set to
   'na-letter'.  Attributes supplied at Job submission time should take
   precedence over the embedded PDL instructions.  However, until
   companies that supply Document data interpreters allow a way for
   external IPP attributes to take precedence over embedded Job
   production instructions, a Printer might not be able to support the
   semantics that IPP attributes override the embedded instructions.

   The IPP Model accounts for this situation by introducing a
   "pdl-override-supported" attribute that describes the Printer's
   capabilities to override instructions embedded in the PDL data
   stream.  The value of the "pdl-override-supported" attribute is
   configured by means outside the scope of this IPP/1.1 document.

   This REQUIRED Printer attribute takes on the following values:

   o  'attempted': This value indicates that the Printer attempts to
      make the IPP attribute values take precedence over embedded
      instructions in the Document data; however, there is no guarantee.

   o  'not-attempted': This value indicates that the Printer makes no
      attempt to make the IPP attribute values take precedence over
      embedded instructions in the Document data.

   At Job processing time, an implementation that supports the value of
   'attempted' might do one of several different actions:

   1)  Generate an Output-Device-specific command sequence to realize
       the feature represented by the IPP attribute value.

   2)  Parse the Document data itself and replace the conflicting
       embedded instruction with a new embedded instruction that matches
       the intent of the IPP attribute value.





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   3)  Indicate to the Printer that external supplied attributes take
       precedence over embedded instructions and then pass the external
       IPP attribute values to the Document data interpreter.

   4)  Anything else that allows for the semantics that IPP attributes
       override embedded Document data instructions.

   Since 'attempted' does not offer any type of guarantee, even though a
   given Printer might not do a very "good" job of attempting to ensure
   that IPP attributes take a higher precedence over instructions
   embedded in the Document data, it would still be a conforming
   implementation.

   At Job processing time, an implementation that supports the value of
   'not-attempted' might do one of the following actions:

   1)  Simply prepend the Document data with the PDL instruction that
       corresponds to the Client-supplied PDL attribute, such that if
       the Document data also has the same PDL instruction it will
       override what the Printer prepended.  In other words, this
       implementation is using the same implementation semantics for the
       Client-supplied IPP attributes as for the Printer defaults.

   2)  Parse the Document data and replace the conflicting embedded
       instruction with a new embedded instruction that approximates,
       but does not match, the semantic intent of the IPP attribute
       value.

   Note: The "ipp-attribute-fidelity" attribute applies to the Printer's
   ability to either accept or reject other unsupported Job Template
   attributes.  In other words, if "ipp-attribute-fidelity" is set to
   'true', a Job is accepted if and only if the Client-supplied Job
   Template attributes and values are supported by the Printer.  Whether
   these attributes actually affect the processing of the Job when the
   Document data contains embedded instructions depends on the ability
   of the Printer to override the instructions embedded in the Document
   data with the semantics of the IPP attributes.  If the Document data
   attributes can be overridden ("pdl-override-supported" set to
   'attempted'), the Printer makes an attempt to use the IPP attributes
   when processing the Job.  If the Document data attributes cannot be
   overridden ("pdl-override-supported" set to 'not-attempted'), the
   Printer makes no attempt to override the embedded Document data
   instructions with the IPP attributes when processing the Job, and
   hence, the IPP attributes can fail to affect the Job processing and
   output when the corresponding instruction is embedded in the
   Document data.





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C.3.  Using Job Template Attributes during Document Processing

   The Printer uses some of the Job's Job Template attributes during the
   processing of the Document data associated with that Job.  These
   include, but are not limited to, "orientation-requested",
   "number-up", "sides", "media", and "copies".  The processing of each
   Document in a Job object MUST follow the steps below.  These steps
   are intended only to identify when and how attributes are to be used
   in processing Document data; any alternative steps that accomplish
   the same effect can be used to implement this specification document.

   1.  Using the Client-supplied "document-format" attribute or some
       form of Document format detection algorithm (if the value of
       "document-format" is not specific enough), determine whether the
       Document data has already been formatted for printing.  If the
       Document data has been formatted, then go to step 2.  Otherwise,
       the Document data MUST be formatted.  The formatting detection
       algorithm is implementation defined and is not specified by this
       document.  The formatting of the Document data uses the
       "orientation-requested" attribute to determine how the formatted
       print data should be placed on an Input Page; see Section 5.2.10
       for details.

   2.  The Document data is a set of Input Pages in a known media type.
       The "page-ranges" attribute is used to select, as specified in
       Section 5.2.7, a sub-sequence of the pages in the print-stream
       that are to be processed and imaged.

   3.  The input for this step is a sequence of Input Pages.  This step
       is controlled by the "number-up" attribute.  If the value of
       "number-up" is N, then during the processing of the Input Pages
       each N Input Pages are positioned, as specified in Section 5.2.9,
       to create a single Impression.  If a given Document does not have
       N more Input Pages, then the completion of the Impression is
       controlled by the "multiple-document-handling" attribute as
       described in Section 5.2.4; when the value of this attribute is
       'single-document' or 'single-document-new-sheet', the Input Pages
       of Document data from subsequent Documents are used to complete
       the Impression.

   The size (scaling), position (translation), and rotation of the Input
   Pages on the Impression are implementation defined.  Note that during
   this process the Input Pages can be rendered to a form suitable for
   placing on the Impression; this rendering is controlled by the values
   of the "printer-resolution" and "print-quality" attributes as
   described in Sections 5.2.12 and 5.2.13.  In the case where N = 1,
   the Impression is nearly the same as the Input Page; the differences




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   would only be in the size, position, and rotation of the Input Page
   and/or any decoration, such as a frame for the page, that is added by
   the implementation.

   1.  The collection of Impressions is placed, in sequence, onto sides
       of the Media Sheets.  This placement is controlled by the "sides"
       attribute and the orientation of the Input Page, as described in
       Section 5.2.8.  The orientation of the Input Pages affects the
       orientation of the Impression; for example, if "number-up" equals
       2, then, typically, two portrait Input Pages become one landscape
       Impression.  Note that the placement of Impressions onto Media
       Sheets is also controlled by the "multiple-document-handling"
       attribute as described in Section 5.2.4.

   2.  The "copies" and "multiple-document-handling" attributes are used
       to determine how many copies of each Media Sheet are printed and
       in what order.  See Sections 5.2.4 and 5.2.5 for details.

   3.  When the correct number of copies are created, the Media Sheets
       are finished according to the values of the "finishings"
       attribute as described in Section 5.2.6.  Note that sometimes
       finishing processes can require manual intervention to perform
       the finishing processes on the copies, especially uncollated
       copies.  This document allows any or all of the processing steps
       to be performed automatically or manually, at the discretion of
       the Printer.

Appendix D.  Generic Directory Schema

   This section defines a generic schema for an entry in a directory
   service.  Implementations of this schema are defined by "Lightweight
   Directory Access Protocol (LDAP): Schema for Printer Services"
   [RFC7612] and "IPP Everywhere" [PWG5100.14].  A directory service is
   a means by which service users can locate service providers.  In IPP
   environments, this means that IPP Printers can be registered (either
   automatically or with the help of an Administrator) as entries of
   type Printer in the directory using an implementation-specific
   mechanism such as entry attributes, entry type fields, specific
   branches, etc.  Directory Clients can search or browse for entries of
   type Printer.  Clients use the directory service to find entries
   based on naming, organizational contexts, or filtered searches on
   attribute values of entries.  For example, a Client can find all
   Printers in the "Local Department" context.  Authentication and
   authorization are also often part of a directory service so that an
   Administrator can place limits on End Users so that they are only
   allowed to find entries to which they have certain access rights.
   IPP itself does not require any specific directory service protocol
   or provider.



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   Note: Some directory implementations allow for the notion of
   "aliasing".  That is, one directory entry object can appear as
   multiple directory entry objects with different names for each
   object.  In each case, each alias refers to the same directory entry
   object, which refers to a single IPP Printer.

   The generic schema is a subset of IPP Printer Job Template and
   Printer Description attributes (Sections 5.2 and 5.4).  These
   attributes are identified as either RECOMMENDED or OPTIONAL for the
   directory entry itself.  This conformance labeling is NOT the same
   conformance labeling applied to the attributes of IPP Printer
   objects.  The conformance labeling in this appendix is intended to
   apply to directory templates and to IPP Printer implementations that
   subscribe by adding one or more entries to a directory.  RECOMMENDED
   attributes SHOULD be associated with each directory entry.  OPTIONAL
   attributes MAY be associated with the directory entry (if known or
   supported).  In addition, all directory entry attributes SHOULD
   reflect the current attribute values for the corresponding Printer.

   As much as possible, the names of attributes in directory schema and
   entries SHOULD be the same as the IPP Printer attribute names as
   shown.

   In order to bridge between the directory service and the IPP Printer,
   one of the RECOMMENDED directory entry attributes is the Printer's
   "printer-uri-supported" attribute.  The directory Client queries the
   "printer-uri-supported" attribute (or its equivalent) in the
   directory entry, and then the IPP Client addresses the IPP Printer
   using one of its URIs.  The "uri-security-supported" attribute
   identifies the protocol (if any) used to secure a channel.

   The attributes in Table 23 define the generic schema for directory
   entries of type Printer.

   +------------------------------------+-------------+----------------+
   | Attribute                          | Conformance | Section        |
   +------------------------------------+-------------+----------------+
   | charset-supported                  | OPTIONAL    | Section 5.4.18 |
   +------------------------------------+-------------+----------------+
   | color-supported                    | RECOMMENDED | Section 5.4.26 |
   +------------------------------------+-------------+----------------+
   | compression-supported              | RECOMMENDED | Section 5.4.32 |
   +------------------------------------+-------------+----------------+
   | document-format-supported          | RECOMMENDED | Section 5.4.22 |
   +------------------------------------+-------------+----------------+
   | finishings-supported               | OPTIONAL    | Section 5.2.6  |





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   +------------------------------------+-------------+----------------+
   | generated-natural-language-        | OPTIONAL    | Section 5.4.20 |
   | supported                          |             |                |
   +------------------------------------+-------------+----------------+
   | ipp-versions-supported             | RECOMMENDED | Section 5.4.14 |
   +------------------------------------+-------------+----------------+
   | media-supported                    | RECOMMENDED | Section 5.2.11 |
   +------------------------------------+-------------+----------------+
   | multiple-document-jobs-supported   | OPTIONAL    | Section 5.4.16 |
   +------------------------------------+-------------+----------------+
   | number-up-supported                | OPTIONAL    | Section 5.2.9  |
   +------------------------------------+-------------+----------------+
   | pages-per-minute-color             | OPTIONAL    | Section 5.4.37 |
   +------------------------------------+-------------+----------------+
   | pages-per-minute                   | OPTIONAL    | Section 5.4.36 |
   +------------------------------------+-------------+----------------+
   | print-quality-supported            | OPTIONAL    | Section 5.2.13 |
   +------------------------------------+-------------+----------------+
   | printer-info                       | OPTIONAL    | Section 5.4.6  |
   +------------------------------------+-------------+----------------+
   | printer-location                   | RECOMMENDED | Section 5.4.5  |
   +------------------------------------+-------------+----------------+
   | printer-make-and-model             | RECOMMENDED | Section 5.4.9  |
   +------------------------------------+-------------+----------------+
   | printer-more-info                  | OPTIONAL    | Section 5.4.7  |
   +------------------------------------+-------------+----------------+
   | printer-name                       | RECOMMENDED | Section 5.4.4  |
   +------------------------------------+-------------+----------------+
   | printer-resolution-supported       | OPTIONAL    | Section 5.2.12 |
   +------------------------------------+-------------+----------------+
   | printer-uri-supported              | RECOMMENDED | Section 5.4.1  |
   +------------------------------------+-------------+----------------+
   | sides-supported                    | RECOMMENDED | Section 5.2.8  |
   +------------------------------------+-------------+----------------+
   | uri-authentication-supported       | RECOMMENDED | Section 5.4.2  |
   +------------------------------------+-------------+----------------+
   | uri-security-supported             | RECOMMENDED | Section 5.4.3  |
   +------------------------------------+-------------+----------------+

                 Table 23: Attributes in Directory Entries











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Acknowledgements

   The authors would like to acknowledge the following individuals for
   their contributions to the original IPP/1.1 specifications:

   Roger deBry, Tom Hastings (original RFC 2911 editor), Robert Herriot,
   Scott A. Isaacson, Kirk Ocke, Patrick Powell, and Peter Zehler

Authors' Addresses

   Michael Sweet
   Apple Inc.
   1 Infinite Loop
   MS 111-HOMC
   Cupertino, CA  95014
   United States of America

   Email: msweet@apple.com


   Ira McDonald
   High North, Inc.
   PO Box 221
   Grand Marais, MI  49839
   United States of America

   Phone: +1 906-494-2434
   Email: blueroofmusic@gmail.com























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