path: root/doc/rfc/rfc2565.txt

Network Working Group                                    R. Herriot, Ed.
Request for Comments: 2565                             Xerox Corporation
Category: Experimental                                         S. Butler
                                                         Hewlett-Packard
                                                                P. Moore
                                                               Microsoft
                                                               R. Turner
                                                              Sharp Labs
                                                              April 1999


         Internet Printing Protocol/1.0: Encoding and Transport

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

IESG Note

   This document defines an Experimental protocol for the Internet
   community.  The IESG expects that a revised version of this protocol
   will be published as Proposed Standard protocol.  The Proposed
   Standard, when published, is expected to change from the protocol
   defined in this memo.  In particular, it is expected that the
   standards-track version of the protocol will incorporate strong
   authentication and privacy features, and that an "ipp:" URL type will
   be defined which supports those security measures.  Other changes to
   the protocol are also possible.  Implementors are warned that future
   versions of this protocol may not interoperate with the version of
   IPP defined in this document, or if they do interoperate, that some
   protocol features may not be available.

   The IESG encourages experimentation with this protocol, especially in
   combination with Transport Layer Security (TLS) [RFC 2246], to help
   determine how TLS may effectively be used as a security layer for
   IPP.








Herriot, et al.               Experimental                      [Page 1]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


Abstract

   This document is one of a set of documents, which together describe
   all aspects of a new Internet Printing Protocol (IPP). IPP is an
   application level protocol that can be used for distributed printing
   using Internet tools and technologies. This document defines the
   rules for encoding IPP operations and IPP attributes into a new
   Internet mime media type called "application/ipp".  This document
   also defines the rules for transporting over HTTP a message body
   whose Content-Type is "application/ipp".

   The full set of IPP documents includes:

      Design Goals for an Internet Printing Protocol [RFC2567]
      Rationale for the Structure and Model and Protocol for the
      Internet Printing Protocol [RFC2568]
      Internet Printing Protocol/1.0: Model and Semantics [RFC2566]
      Internet Printing Protocol/1.0: Encoding and Transport (this
      document)
      Internet Printing Protocol/1.0: Implementer's Guide [ipp-iig]
      Mapping between LPD and IPP Protocols [RFC2569]

   The document, "Design Goals for an Internet Printing Protocol", takes
   a broad look at distributed printing functionality, and it enumerates
   real-life scenarios that help to clarify the features that need to be
   included in a printing protocol for the Internet. It identifies
   requirements for three types of users: end users, operators, and
   administrators. It calls out a subset of end user requirements that
   are satisfied in IPP/1.0. Operator and administrator requirements are
   out of scope for version 1.0.

   The document, "Rationale for the Structure and Model and Protocol for
   the Internet Printing Protocol", describes IPP from a high level
   view, defines a roadmap for the various documents that form the suite
   of IPP specifications, and gives background and rationale for the
   IETF working group's major decisions.

   The document, "Internet Printing Protocol/1.0: Model and Semantics",
   describes a simplified model with abstract objects, their attributes,
   and their operations that are independent of encoding and transport.
   It introduces a Printer and a Job object. The Job object optionally
   supports multiple documents per Job. It also addresses security,
   internationalization, and directory issues.

   This document "Internet Printing Protocol/1.0: Implementer's Guide",
   gives advice to implementers of IPP clients and IPP objects.





Herriot, et al.               Experimental                      [Page 2]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   The document "Mapping between LPD and IPP Protocols" gives some
   advice to implementers of gateways between IPP and LPD (Line Printer
   Daemon) implementations.

Table of Contents

   1. Introduction.....................................................4
   2. Conformance Terminology..........................................4
   3. Encoding of  the Operation Layer.................................4
      3.1  Picture of the Encoding.....................................5
      3.2  Syntax of Encoding..........................................7
      3.3  Version-number..............................................9
      3.4  Operation-id................................................9
      3.5  Status-code.................................................9
      3.6  Request-id..................................................9
      3.7  Tags.......................................................10
         3.7.1 Delimiter Tags.........................................10
         3.7.2 Value Tags.............................................11
      3.8  Name-Length................................................13
      3.9  (Attribute) Name...........................................13
      3.10 Value Length...............................................16
      3.11 (Attribute) Value..........................................16
      3.12 Data.......................................................18
   4. Encoding of Transport Layer.....................................18
   5. Security Considerations.........................................19
      5.1  Using IPP with SSL3........................................19
   6. References......................................................20
   7. Authors' Addresses..............................................22
   8. Other Participants:.............................................24
   9. Appendix A: Protocol Examples...................................25
      9.1  Print-Job Request..........................................25
      9.2  Print-Job Response (successful)............................26
      9.3  Print-Job Response (failure)...............................27
      9.4  Print-Job Response (success with attributes ignored).......28
      9.5  Print-URI Request..........................................30
      9.6  Create-Job Request.........................................31
      9.7  Get-Jobs Request...........................................31
      9.8  Get-Jobs Response..........................................32
   10. Appendix C: Registration of MIME Media Type Information for
       "application/ipp"..............................................35
   11. Full Copyright Statement.......................................37










Herriot, et al.               Experimental                      [Page 3]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


1. Introduction

   This document contains the rules for encoding IPP operations and
   describes two layers: the transport layer and the operation layer.

   The transport layer consists of an  HTTP/1.1 request or response. RFC
   2068 [RFC2068] describes HTTP/1.1. This document specifies the HTTP
   headers that an IPP implementation supports.

   The operation layer consists of  a message body in an HTTP request or
   response.  The document "Internet Printing Protocol/1.0: Model and
   Semantics" [RFC2566] defines the semantics of such a message body and
   the supported values. This document specifies the encoding of an IPP
   operation. The aforementioned document [RFC2566] is henceforth
   referred to as the "IPP model document"

2. Conformance Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "MAY", and  "OPTIONAL" in this document are to be
   interpreted as described in RFC 2119 [RFC2119].

3. Encoding of  the Operation Layer

   The operation layer MUST contain a single operation request or
   operation response.  Each request or response consists of a sequence
   of values and attribute groups. Attribute groups consist of a
   sequence of attributes each of which is a name and value.  Names and
   values are ultimately sequences of octets

   The encoding consists of octets as the most primitive type. There are
   several types built from octets, but three important types are
   integers, character strings and octet strings, on which most other
   data types are built. Every character string in this encoding MUST be
   a sequence of characters where the characters are associated with
   some charset and some natural language. A character string MUST be in
   "reading order" with the first character in the value (according to
   reading order) being the first character in the encoding. A character
   string whose associated charset is US-ASCII whose associated natural
   language is US English is henceforth called a US-ASCII-STRING. A
   character string whose associated charset and natural language are
   specified in a request or response as described in the model document
   is henceforth called a LOCALIZED-STRING. An octet string MUST be in
   "IPP model document order" with the first octet in the value
   (according to the IPP model document order) being the first octet in
   the encoding Every integer in this encoding MUST be encoded as a
   signed integer using two's-complement binary encoding with big-endian
   format (also known as "network order" and "most significant byte



Herriot, et al.               Experimental                      [Page 4]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   first"). The number of octets for an integer MUST be 1, 2 or 4,
   depending on usage in the protocol.  Such one-octet integers,
   henceforth called SIGNED-BYTE, are used for the version-number and
   tag fields. Such two-byte integers, henceforth called SIGNED-SHORT
   are used for the operation-id, status-code and length fields. Four
   byte integers, henceforth called SIGNED-INTEGER, are used for values
   fields and the sequence number.

   The following two sections present the operation layer in two ways

      - informally through pictures and description
      - formally through Augmented Backus-Naur Form (ABNF), as specified
        by RFC 2234 [RFC2234]

3.1 Picture of the Encoding

   The encoding for an operation request or response consists of:

  -----------------------------------------------
  |                  version-number             |   2 bytes  - required
  -----------------------------------------------
  |               operation-id (request)        |
  |                      or                     |   2 bytes  - required
  |               status-code (response)        |
  -----------------------------------------------
  |                   request-id                |   4 bytes  - required
  -----------------------------------------------------------
  |               xxx-attributes-tag            |   1 byte  |
  -----------------------------------------------           |-0 or more
  |             xxx-attribute-sequence          |   n bytes |
  -----------------------------------------------------------
  |              end-of-attributes-tag          |   1 byte   - required
  -----------------------------------------------
  |                     data                    |   q bytes  - optional
  -----------------------------------------------

   The xxx-attributes-tag and xxx-attribute-sequence represents four
   different values of "xxx", namely, operation, job, printer and
   unsupported. The xxx-attributes-tag and an xxx-attribute-sequence
   represent attribute groups in the model document. The xxx-
   attributes-tag identifies the attribute group and the xxx-attribute-
   sequence contains the attributes.

   The expected sequence of  xxx-attributes-tag and xxx-attribute-
   sequence is specified in the IPP model document for each operation
   request and operation response.





Herriot, et al.               Experimental                      [Page 5]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   A request or response SHOULD contain each xxx-attributes-tag defined
   for that request or response even if there are no attributes except
   for the unsupported-attributes-tag which SHOULD be present only if
   the unsupported-attribute-sequence is non-empty. A receiver of a
   request MUST be able to process as equivalent empty attribute groups:

     a) an xxx-attributes-tag with an empty xxx-attribute-sequence,
     b) an expected but missing xxx-attributes-tag.

   The data is omitted from some operations, but the end-of-attributes-
   tag is present even when the data is omitted. Note, the xxx-
   attributes-tags and end-of-attributes-tag are called 'delimiter-
   tags'. Note: the xxx-attribute-sequence, shown above may consist of 0
   bytes, according to the rule below.

   An xxx-attributes-sequence consists of zero or more compound-
   attributes.

  -----------------------------------------------
  |              compound-attribute             |   s bytes - 0 or more
  -----------------------------------------------

   A compound-attribute consists of an attribute with a single value
   followed by zero or more additional values.

   Note: a 'compound-attribute' represents a single attribute in the
   model document.  The 'additional value' syntax is for attributes with
   2 or more values.

   Each attribute consists of:

  -----------------------------------------------
  |                   value-tag                 |   1 byte
  -----------------------------------------------
  |               name-length  (value is u)     |   2 bytes
  -----------------------------------------------
  |                     name                    |   u bytes
  -----------------------------------------------
  |              value-length  (value is v)     |   2 bytes
  -----------------------------------------------
  |                     value                   |   v bytes
  -----------------------------------------------









Herriot, et al.               Experimental                      [Page 6]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   An additional value consists of:

  -----------------------------------------------------------
  |                   value-tag                 |   1 byte  |
  -----------------------------------------------           |
  |            name-length  (value is 0x0000)   |   2 bytes |
  -----------------------------------------------           |-0 or more
  |              value-length (value is w)      |   2 bytes |
  -----------------------------------------------           |
  |                     value                   |   w bytes |
  -----------------------------------------------------------

   Note: an additional value is like an attribute whose name-length is 0.

   From the standpoint of a parsing loop, the encoding consists of:

  -----------------------------------------------
  |                  version-number             |   2 bytes  - required
  -----------------------------------------------
  |               operation-id (request)        |
  |                      or                     |   2 bytes  - required
  |               status-code (response)        |
  -----------------------------------------------
  |                   request-id                |   4 bytes  - required
  -----------------------------------------------------------
  |        tag (delimiter-tag or value-tag)     |   1 byte  |
  -----------------------------------------------           |-0 or more
  |           empty or rest of attribute        |   x bytes |
  -----------------------------------------------------------
  |              end-of-attributes-tag          |   2 bytes  - required
  -----------------------------------------------
  |                     data                    |   y bytes  - optional
  -----------------------------------------------

   The value of the tag determines whether the bytes following the
   tag are:

      - attributes
      - data
      - the remainder of a single attribute where the tag specifies the
        type of the value.

3.2 Syntax of Encoding

   The syntax below is ABNF [RFC2234] except 'strings of literals' MUST
   be case sensitive. For example 'a' means lower case  'a' and not
   upper case 'A'.   In addition, SIGNED-BYTE and SIGNED-SHORT fields
   are represented as '%x' values which show their range of values.



Herriot, et al.               Experimental                      [Page 7]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


  ipp-message = ipp-request / ipp-response
  ipp-request = version-number operation-id request-id
           *(xxx-attributes-tag  xxx-attribute-sequence)
           end-of-attributes-tag data
  ipp-response = version-number status-code request-id
           *(xxx-attributes-tag xxx-attribute-sequence)
           end-of-attributes-tag data
  xxx-attribute-sequence = *compound-attribute

  xxx-attributes-tag = operation-attributes-tag / job-attributes-tag /
        printer-attributes-tag / unsupported-attributes-tag

  version-number = major-version-number minor-version-number
  major-version-number = SIGNED-BYTE  ; initially %d1
  minor-version-number = SIGNED-BYTE  ; initially %d0

  operation-id = SIGNED-SHORT    ; mapping from model defined below
  status-code = SIGNED-SHORT  ; mapping from model defined below
  request-id = SIGNED-INTEGER ; whose value is > 0

  compound-attribute = attribute *additional-values
  attribute = value-tag name-length name value-length value
  additional-values = value-tag zero-name-length value-length value

  name-length = SIGNED-SHORT    ; number of octets of 'name'
  name = LALPHA *( LALPHA / DIGIT / "-" / "_" / "." )
  value-length = SIGNED-SHORT  ; number of octets of 'value'
  value = OCTET-STRING

  data = OCTET-STRING

  zero-name-length = %x00.00           ; name-length of 0
  operation-attributes-tag =  %x01             ; tag of 1
  job-attributes-tag   =  %x02                 ; tag of 2
  printer-attributes-tag =  %x04               ; tag of 4
  unsupported-attributes-tag =  %x05          ; tag of 5
  end-of-attributes-tag = %x03                 ; tag of 3
  value-tag = %x10-FF

  SIGNED-BYTE = BYTE
  SIGNED-SHORT = 2BYTE
  SIGNED-INTEGER = 4BYTE
  DIGIT = %x30-39    ;  "0" to "9"
  LALPHA = %x61-7A   ;  "a" to "z"
  BYTE = %x00-FF
  OCTET-STRING = *BYTE





Herriot, et al.               Experimental                      [Page 8]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   The syntax allows an xxx-attributes-tag to be present when the xxx-
   attribute-sequence that follows is empty. The syntax is defined this
   way to allow for the response of Get-Jobs where no attributes are
   returned for some job-objects.  Although it is RECOMMENDED that the
   sender not send an xxx-attributes-tag if there are no attributes
   (except in the Get-Jobs response just mentioned), the receiver MUST
   be able to decode such syntax.

3.3 Version-number

   The version-number MUST consist of a major and minor version-number,
   each of which MUST be represented by a SIGNED-BYTE. The protocol
   described in this document MUST have a major version-number of 1
   (0x01) and a minor version-number of  0 (0x00).  The ABNF for these
   two bytes MUST be %x01.00.

3.4 Operation-id

   Operation-ids are defined as enums in the model document. An
   operation-ids enum value MUST be encoded as a SIGNED-SHORT.

   Note: the values 0x4000 to 0xFFFF are reserved for private
   extensions.

3.5 Status-code

   Status-codes are defined as enums in the model document. A status-
   code enum value MUST be encoded as a SIGNED-SHORT.

   The status-code is an operation attribute in the model document. In
   the protocol, the status-code is in a special position, outside of
   the operation attributes.

   If an IPP status-code is returned, then the HTTP Status-Code MUST be
   200 (successful-ok).  With any other HTTP Status-Code value, the HTTP
   response MUST NOT contain an IPP message-body, and thus no IPP
   status-code is returned.

3.6 Request-id

   The request-id allows a client to match a response with a request.
   This mechanism is unnecessary in HTTP, but may be useful when
   application/ipp entity bodies are used in another context.

   The request-id in a response MUST be the value of the request-id
   received in the corresponding request.  A client can set the
   request-id in each request to a unique value or a constant value,
   such as 1, depending on what the client does with the request-id



Herriot, et al.               Experimental                      [Page 9]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   returned in the response. The value of the request-id MUST be greater
   than zero.

3.7 Tags

   There are two kinds of tags:

      - delimiter tags: delimit major sections of the protocol, namely
        attributes and data
      - value tags: specify the type of each attribute value

3.7.1 Delimiter Tags

   The following table specifies the values for the delimiter tags:

      Tag Value (Hex)   Delimiter

      0x00              reserved
      0x01              operation-attributes-tag
      0x02              job-attributes-tag
      0x03              end-of-attributes-tag
      0x04              printer-attributes-tag
      0x05              unsupported-attributes-tag
      0x06-0x0e         reserved for future delimiters
      0x0F              reserved for future chunking-end-of-attributes-
                         tag

   When an xxx-attributes-tag occurs in the protocol, it MUST mean that
   zero or more following attributes up to the next delimiter tag are
   attributes belonging to group xxx as defined in the model document,
   where xxx is operation, job, printer, unsupported.

   Doing substitution for xxx in the above paragraph, this means the
   following. When an operation-attributes-tag occurs in the protocol,
   it MUST mean that the zero or more following attributes up to the
   next delimiter tag are operation attributes as defined in the model
   document.  When an job-attributes-tag occurs in the protocol, it MUST
   mean that the zero or more following attributes up to the next
   delimiter tag are job attributes or job template attributes as
   defined in the model document.  When a printer-attributes-tag occurs
   in the protocol, it MUST mean that the zero or more following
   attributes up to the next delimiter tag are printer attributes as
   defined in the model document. When an unsupported-attributes-tag
   occurs in the protocol, it MUST mean that the zero or more following
   attributes up to the next delimiter tag are unsupported attributes as
   defined in the model document.





Herriot, et al.               Experimental                     [Page 10]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   The operation-attributes-tag and end-of-attributes-tag MUST each
   occur exactly once in an operation. The operation-attributes-tag MUST
   be the first tag delimiter, and the end-of-attributes-tag MUST be the
   last tag delimiter. If the operation has a document-content group,
   the document data in that group MUST follow the end-of-attributes-
   tag.

   Each of the  other three  xxx-attributes-tags defined above is
   OPTIONAL in an operation and each MUST occur at most once in an
   operation, except for job-attributes-tag in a Get-Jobs response which
   may occur zero or more times.

   The order and presence of delimiter tags for each operation request
   and each operation response MUST be that defined in the model
   document. For further details, see section 3.9 "(Attribute) Name" and
   section 9 "Appendix A: Protocol Examples".

   A Printer MUST treat the reserved delimiter tags differently from
   reserved value tags so that the Printer knows that there is an entire
   attribute group that it doesn't understand as opposed to a single
   value that it doesn't understand.

3.7.2 Value Tags

   The remaining tables show values for the value-tag, which is the
   first octet of  an attribute. The value-tag specifies the type of the
   value of the attribute. The following table specifies the "out-of-
   band" values for the value-tag.

      Tag Value (Hex) Meaning

      0x10            unsupported
      0x11            reserved for future 'default'
      0x12            unknown
      0x13            no-value

      Tag Value (Hex) Meaning

      0x14-0x1F       reserved for future "out-of-band" values.

   The "unsupported" value MUST be used in the attribute-sequence of an
   error response for those attributes which the printer does not
   support.  The "default" value is reserved for future use of setting
   value back to their default value. The "unknown" value is used for
   the value of a supported attribute when its value is temporarily
   unknown.  The "no-value" value is used for a supported attribute to
   which




Herriot, et al.               Experimental                     [Page 11]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   no value has been assigned, e.g. "job-k-octets-supported" has no
   value if an implementation supports this attribute, but an
   administrator has not configured the printer to have a limit.

   The following table specifies the integer values for the value-tag:

      Tag Value (Hex)  Meaning

      0x20             reserved
      0x21             integer
      0x22             boolean
      0x23             enum
      0x24-0x2F        reserved for future integer types

   NOTE: 0x20 is reserved for "generic integer" if it should ever be
   needed.

   The following table specifies the octetString values for the value-
   tag:

      Tag Value (Hex)  Meaning

      0x30             octetString with an  unspecified format
      0x31             dateTime
      0x32             resolution
      0x33             rangeOfInteger
      0x34             reserved for collection (in the future)
      0x35             textWithLanguage
      0x36             nameWithLanguage
      0x37-0x3F        reserved for future octetString types

   The following table specifies the character-string values for the
   value-tag:

      Tag Value (Hex)  Meaning

      0x40             reserved
      0x41             textWithoutLanguage
      0x42             nameWithoutLanguage
      0x43             reserved
      0x44             keyword
      0x45             uri
      0x46             uriScheme
      0x47             charset
      0x48             naturalLanguage






Herriot, et al.               Experimental                     [Page 12]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


      Tag Value (Hex)  Meaning

      0x49             mimeMediaType
      0x4A-0x5F        reserved for future character string types

   NOTE: 0x40 is reserved for "generic character-string" if it should
   ever be needed.

   NOTE:  an attribute value always has a type, which is explicitly
   specified by its tag; one such tag value is "nameWithoutLanguage".
   An attribute's name has an implicit type, which is keyword.

   The values 0x60-0xFF are reserved for future types. There are no
   values allocated for private extensions. A new type MUST be
   registered via the type 2 registration process [RFC2566].

   The tag 0x7F is reserved for extending types beyond the 255 values
   available with a single byte. A tag value of 0x7F MUST signify that
   the first 4 bytes of the value field are interpreted as the tag
   value.  Note, this future extension doesn't affect parsers that  are
   unaware of this special tag. The tag is like any other unknown tag,
   and the value length specifies the length of a value which contains a
   value that the parser treats atomically.  All these 4 byte tag values
   are currently unallocated except that the values 0x40000000-
   0x7FFFFFFF are reserved for experimental use.

3.8 Name-Length

   The name-length field MUST consist of a SIGNED-SHORT. This field MUST
   specify the number of octets in the name field which follows the
   name-length field, excluding the two bytes of the name-length field.

   If a name-length field has a value of zero, the following name field
   MUST be empty, and the following value MUST be treated as an
   additional value for the preceding attribute. Within an attribute-
   sequence, if two attributes have the same name, the first occurrence
   MUST be ignored. The zero-length name is the only mechanism for
   multi-valued attributes.

3.9 (Attribute) Name

   Some operation elements are called parameters in the model document
   [RFC2566]. They MUST be encoded in a special position and they MUST
   NOT appear as an operation attributes.  These parameters are:

      - "version-number": The parameter  named "version-number" in the
        IPP model document MUST become the "version-number" field in the
        operation layer request or response.



Herriot, et al.               Experimental                     [Page 13]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


      - "operation-id": The parameter named "operation-id" in the IPP
        model document MUST become the "operation-id" field in the
        operation layer request.
      - "status-code": The parameter named "status-code" in the IPP
        model document MUST become the "status-code" field in the
        operation layer response.
      - "request-id": The parameter named "request-id" in the IPP model
        document MUST become the "request-id" field in the operation
        layer request or response.

   All Printer and Job objects are identified by a Uniform Resource
   Identifier (URI) [RFC2396] so that they can be persistently and
   unambiguously referenced.  The notion of a URI is a useful concept,
   however, until the notion of URI is more stable (i.e.,  defined more
   completely and deployed more widely), it is expected that the URIs
   used for IPP objects will actually be URLs [RFC1738]  [RFC1808].
   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.

   Some operation elements are encoded twice, once as the request-URI on
   the HTTP Request-Line and a second time as a REQUIRED operation
   attribute in the application/ipp entity.  These attributes are the
   target URI for the operation:

      - "printer-uri": When the target is a printer and the transport is
        HTTP or HTTPS (for SSL3 [ssl]), the target printer-uri defined
        in each operation in the IPP model document MUST be an operation
        attribute called "printer-uri" and it MUST also be specified
        outside of  the operation layer as the request-URI on the
        Request-Line at the HTTP level.
      - "job-uri": When the target is a job and the transport is HTTP or
        HTTPS (for SSL3), the target job-uri of each operation in the
        IPP model document MUST be an operation attribute called "job-
        uri" and it MUST also be specified outside of  the operation
        layer as the request-URI on the Request-Line at the HTTP level.

   Note: The target URI is included twice in an operation referencing
   the same IPP object, but the two URIs NEED NOT be literally
   identical. One can be a relative URI and the other can be an absolute
   URI.  HTTP/1.1 allows clients to generate and send a relative URI
   rather than an absolute URI.  A relative URI identifies a resource
   with the scope of the HTTP server, but does not include scheme, host
   or port.  The following statements characterize how URLs should be
   used in the mapping of IPP onto HTTP/1.1:






Herriot, et al.               Experimental                     [Page 14]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


      1. Although potentially redundant, a client MUST supply the target
         of the operation both as an operation attribute and as a URI at
         the HTTP layer.  The rationale for this decision is to maintain
         a consistent set of rules for mapping application/ipp to
         possibly many communication layers, even where URLs are not
         used as the addressing mechanism in the transport layer.
      2. Even though these two URLs might not be literally identical
         (one being relative and the other being absolute), they MUST
         both reference the same IPP object.
      3. The URI in the HTTP layer is either relative or absolute and is
         used by the HTTP server to route the HTTP request to the
         correct resource relative to that HTTP server.  The HTTP server
         need not be aware of the URI within the operation request.
      4. Once the HTTP server resource begins to process the HTTP
         request, it might get the reference to the appropriate IPP
         Printer object from either the HTTP URI (using to the context
         of the HTTP server for relative URLs) or from the URI within
         the operation request; the choice is up to the implementation.
      5. HTTP URIs can be relative or absolute, but the target URI in
         the operation MUST be an absolute URI.

   The model document arranges the remaining attributes into groups for
   each operation request and response. Each such group MUST be
   represented in the protocol by an xxx-attribute-sequence preceded by
   the appropriate xxx-attributes-tag (See the table below and section 9
   "Appendix A:  Protocol Examples"). In addition, the order of these
   xxx-attributes-tags and xxx-attribute-sequences in the protocol MUST
   be the same as in the model document, but the order of attributes
   within each xxx-attribute-sequence MUST be unspecified. The table
   below maps the model document group name to xxx-attributes-sequence:

   Model Document Group           xxx-attributes-sequence

   Operation Attributes           operations-attributes-sequence
   Job Template Attributes        job-attributes-sequence
   Job Object Attributes          job-attributes-sequence
   Unsupported Attributes         unsupported-attributes-sequence
   Requested Attributes           job-attributes-sequence
   Get-Job-Attributes)
   Requested Attributes           printer-attributes-sequence
   Get-Printer-Attributes)
   Document Content               in a special position as described
                                  above

   If an operation contains attributes from more than one job object
   (e.g.  Get-Jobs response), the attributes from each job object MUST
   be in a separate job-attribute-sequence, such that the attributes




Herriot, et al.               Experimental                     [Page 15]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   from the ith job object are in the ith job-attribute-sequence. See
   Section 9 "Appendix A: Protocol Examples" for table showing the
   application of the rules above.

3.10 Value Length

   Each attribute value MUST be preceded by a SIGNED-SHORT, which MUST
   specify the number of octets in the value which follows this length,
   exclusive of the two bytes specifying the length.

   For any of the types represented by binary signed integers, the
   sender MUST encode the value in exactly four octets.

   For any of the types represented by character-strings, the sender
   MUST encode the value with all the characters of the string and
   without any padding characters.

   If a value-tag contains an "out-of-band" value, such as
   "unsupported", the value-length MUST be 0 and the value empty. The
   value has no meaning when the value-tag has an "out-of-band" value.
   If a client receives a response with a nonzero value-length in this
   case, it MUST ignore the value field. If a printer receives a request
   with a nonzero value-length in this case, it MUST reject the request.

3.11 (Attribute) Value

   The syntax types and most of the details of their representation are
   defined in the IPP model document. The table below augments the
   information in the model document, and defines the syntax types from
   the model document in terms of the 5 basic types defined in section 3
   "Encoding of the Operation Layer". The 5 types are US-ASCII-STRING,
   LOCALIZED-STRING, SIGNED-INTEGER, SIGNED-SHORT, SIGNED-BYTE, and
   OCTET-STRING.

Syntax of Attribute  Encoding
Value

textWithoutLanguage, LOCALIZED-STRING.
nameWithoutLanguage

textWithLanguage     OCTET_STRING consisting of 4 fields:
                       a) a SIGNED-SHORT which is the number of octets
                          in the following field
                       b) a value of type natural-language,
                       c) a SIGNED-SHORT which is the number of octets
                          in the following field,
                       d) a value of type textWithoutLanguage.




Herriot, et al.               Experimental                     [Page 16]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


                      The length of a textWithLanguage value MUST be 4
                      + the value of field a + the value of field c.

nameWithLanguage     OCTET_STRING consisting of 4 fields:
                       a) a SIGNED-SHORT which is the number of octets
                          in the following field
                       b) a value of type natural-language,
                       c) a SIGNED-SHORT which is the number of octets
                          in the following field
                       d) a value of type nameWithoutLanguage.

                      The length of a nameWithLanguage value MUST be 4
                      + the value of field a + the value of field c.

charset,             US-ASCII-STRING.
naturalLanguage,
mimeMediaType,
keyword, uri, and
uriScheme

boolean              SIGNED-BYTE  where 0x00 is 'false' and 0x01 is
                      'true'.

Syntax of Attribute  Encoding
Value


integer and enum     a SIGNED-INTEGER.

dateTime             OCTET-STRING consisting of eleven octets whose
                      contents are defined by "DateAndTime" in RFC
                      2579 [RFC2579].

resolution           OCTET_STRING consisting of nine octets of  2
                      SIGNED-INTEGERs followed by a SIGNED-BYTE. The
                      first SIGNED-INTEGER contains the value of cross
                      feed direction resolution. The second SIGNED-
                      INTEGER contains the value of feed direction
                      resolution. The SIGNED-BYTE contains the units
                      value.

rangeOfInteger       Eight octets consisting of 2 SIGNED-INTEGERs.
                      The first SIGNED-INTEGER contains the lower
                      bound and the second SIGNED-INTEGER contains the
                      upper  bound.






Herriot, et al.               Experimental                     [Page 17]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


1setOf  X            Encoding according to the rules for an attribute
                      with more than 1 value.  Each value X is encoded
                      according to the rules for encoding its type.

octetString          OCTET-STRING

   The type of the value in the model document determines the encoding
   in the value and the value of the value-tag.

3.12 Data

   The data part MUST include any data required by the operation

4. Encoding of Transport Layer

   HTTP/1.1 [RFC2068] is the transport layer for this protocol.

   The operation layer has been designed with the assumption that the
   transport layer contains the following information:

      - the URI of the target job or printer operation
      - the total length of the data in the operation layer, either as a
        single length or as a sequence of chunks each with a length.

   It is REQUIRED that a printer implementation support HTTP over the
   IANA assigned Well Known Port 631 (the IPP default port), though a
   printer implementation may support HTTP over some other port as well.
   In addition, a printer may have to support another port for privacy
   (See Section 5 "Security Considerations").

   Note: even though port 631 is the IPP default, port 80 remains the
   default for an HTTP URI.  Thus a URI for a printer using port 631
   MUST contain an explicit port, e.g. "http://forest:631/pinetree".  An
   HTTP URI for IPP with no explicit port implicitly reference port 80,
   which is consistent with the rules for HTTP/1.1. Each HTTP operation
   MUST use the POST method where the request-URI is the object target
   of the operation, and where the "Content-Type" of the message-body in
   each request and response MUST be "application/ipp". The message-body
   MUST contain the operation layer and MUST have the syntax described
   in section 3.2 "Syntax of Encoding". A client implementation MUST
   adhere to the rules for a client described for HTTP1.1 [RFC2068]. A
   printer (server) implementation MUST adhere the rules for an origin
   server described for HTTP1.1 [RFC2068].

   An IPP server sends a response for each request that it receives.  If
   an IPP server detects an error, it MAY send a response before it has
   read the entire request.  If the HTTP layer of the IPP server
   completes processing the HTTP headers successfully, it MAY send an



Herriot, et al.               Experimental                     [Page 18]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   intermediate response, such as "100 Continue", with no IPP data
   before sending the IPP response.  A client MUST expect such a variety
   of responses from an IPP server. For further information on HTTP/1.1,
   consult the HTTP documents [RFC2068].

5. Security Considerations

   The IPP Model document defines an IPP implementation with "privacy"
   as one that implements Secure Socket Layer Version 3 (SSL3).  Note:
   SSL3 is not an IETF standards track specification. SSL3 meets the
   requirements for IPP security with regards to features such as mutual
   authentication and privacy (via encryption). The IPP Model document
   also outlines IPP-specific security considerations and should be the
   primary reference for security implications with regards to the IPP
   protocol itself.

   The IPP Model document defines an IPP implementation with
   "authentication" as one that implements the standard way for
   transporting IPP messages within HTTP 1.1. These include the security
   considerations outlined in the HTTP 1.1 standard document [RFC2068]
   and Digest Access Authentication extension [RFC2069].

   The current HTTP infrastructure supports HTTP over TCP port 80. IPP
   server implementations MUST offer IPP services using HTTP over the
   IANA assigned Well Known Port 631 (the IPP default port). IPP server
   implementations may support other ports, in addition to this port.

   See further discussion of IPP security concepts in the model document
   [RFC2566].

5.1 Using IPP with SSL3

   An assumption is that the URI for a secure IPP Printer object has
   been found by means outside the IPP printing protocol, via a
   directory service, web site or other means.

   IPP provides a transparent connection to SSL by calling the
   corresponding URL (a https URI connects by default to port 443).
   However, the following functions can be provided to ease the
   integration of IPP with SSL during implementation:

      connect (URI), returns a status

         "connect" makes an https call and returns the immediate status
         of the connection as returned by SSL to the user. The status
         values are explained in section 5.4.2 of the SSL document
         [ssl].




Herriot, et al.               Experimental                     [Page 19]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


         A session-id may also be retained to later resume a session.
         The SSL handshake protocol may also require the cipher
         specifications supported by the client, key length of the
         ciphers, compression methods, certificates, etc. These should
         be sent to the server and hence should be available to the IPP
         client (although as part of administration features).

      disconnect (session)

         to disconnect a particular session.

         The session-id available from the "connect" could be used.

      resume (session)

         to reconnect using a previous session-id.

   The availability of this information as administration features are
   left for implementers, and need not be specified at this time.

6. References

   [RFC2278] Freed, N. and J. Postel, "IANA Charset Registration
             Procedures", BCP 19, RFC 2278, January 1998.

   [dpa]     ISO/IEC 10175 Document Printing Application (DPA), June
             1996.

   [iana]    IANA Registry of Coded Character Sets:
             ftp://ftp.isi.edu/in-notes/iana/assignments/character-sets.

   [ipp-iig] Hastings, Tom, et al., "Internet Printing Protocol/1.0:
             Implementer's Guide", Work in Progress.

   [RFC2569] Herriot, R., Hastings, T., Jacobs, N. and J. Martin,
             "Mapping between LPD and IPP Protocols", RFC 2569, April
             1999.

   [RFC2566] deBry, R., Hastings, T., Herriot, R., Isaacson, S. and P.
             Powell, "Internet Printing Protocol/1.0: Model and
             Semantics", RFC 2566, April 1999.

   [RFC2565] Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet
             Printing Protocol/1.0: Encoding and Transport", RFC 2565,
             April 1999.






Herriot, et al.               Experimental                     [Page 20]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   [RFC2568] Zilles, S., "Rationale for the Structure and Model and
             Protocol for the Internet Printing Protocol", RFC 2568,
             April 1999.

   [RFC2567] Wright, D., "Design Goals for an Internet Printing
             Protocol", RFC 2567, April 1999.

   [RFC822]  Crocker, D., "Standard for the Format of ARPA Internet Text
             Messages", STD 11, RFC 822, August 1982.

   [RFC1123] Braden, R., "Requirements for Internet Hosts - Application
             and Support", STD 3, RFC 1123, October 1989.

   [RFC1179] McLaughlin, L. III, (editor), "Line Printer Daemon
             Protocol" RFC 1179, August 1990.

   [RFC2223] Postel, J. and J. Reynolds, "Instructions to RFC Authors",
             RFC 2223, October 1997.

   [RFC1738] Berners-Lee, T., Masinter, L. and M. McCahill, "Uniform
             Resource Locators (URL)", RFC 1738, December 1994.

   [RFC1759] Smith, R., Wright, F., Hastings, T., Zilles, S. and J.
             Gyllenskog, "Printer MIB", RFC 1759, March 1995.

   [RFC1766] Alvestrand, H., " Tags for the Identification of
             Languages", RFC 1766, March 1995.

   [RFC1808] Fielding, R., "Relative Uniform Resource Locators", RFC
             1808, June 1995.

   [RFC2579] McCloghrie, K., Perkins, D. and J. Schoenwaelder, "Textual
             Conventions for SMIv2", STD 58, RFC 2579, April 1999.

   [RFC2046] Freed, N. and N. Borenstein, Multipurpose Internet Mail
             Extensions (MIME) Part Two: Media Types", RFC 2046,
             November 1996.

   [RFC2048] Freed, N., Klensin J. and J. Postel.  Multipurpose Internet
             Mail Extension (MIME) Part Four: Registration Procedures",
             BCP 13, RFC 2048, November 1996.

   [RFC2068] Fielding, R., Gettys, J., Mogul, J., Frystyk, H. and T.
             Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC
             2068, January 1997.






Herriot, et al.               Experimental                     [Page 21]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   [RFC2069] Franks, J., Hallam-Baker, P., Hostetler, J., Leach, P.,
             Luotonen, A., Sink, E. and L. Stewart, "An Extension to
             HTTP: Digest Access Authentication", RFC 2069, January
             1997.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2184] Freed, N. and K. Moore, "MIME Parameter Value and Encoded
             Word Extensions: Character Sets, Languages, and
             Continuations", RFC 2184, August 1997.

   [RFC2234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
             Specifications: ABNF", RFC 2234. November 1997.

   [RFC2396] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
             Resource Identifiers (URI): Generic Syntax", RFC 2396,
             August 1998.

7. Authors' Addresses

   Robert Herriot (Editor)
   Xerox Corporation
   3400 Hillview Ave., Bldg #1
   Palo Alto, CA 94304

   Phone: 650-813-7696
   Fax:  650-813-6860
   EMail: rherriot@pahv.xerox.com


   Sylvan Butler
   Hewlett-Packard
   11311 Chinden Blvd.
   Boise, ID 83714

   Phone: 208-396-6000
   Fax: 208-396-3457
   EMail: sbutler@boi.hp.com












Herriot, et al.               Experimental                     [Page 22]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   Paul Moore
   Microsoft
   One Microsoft Way
   Redmond, WA 98053

   Phone: 425-936-0908
   Fax: 425-93MS-FAX
   EMail: paulmo@microsoft.com


   Randy Turner
   Sharp Laboratories
   5750 NW Pacific Rim Blvd
   Camas, WA 98607

   Phone: 360-817-8456
   Fax: 360-817-8436
   EMail: rturner@sharplabs.com


   IPP Mailing List:  ipp@pwg.org
   IPP Mailing List Subscription:  ipp-request@pwg.org
   IPP Web Page:  http://www.pwg.org/ipp/




























Herriot, et al.               Experimental                     [Page 23]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


8. Other Participants:

   Chuck Adams - Tektronix          Harry Lewis - IBM
   Ron Bergman - Dataproducts       Tony Liao - Vivid Image
   Keith Carter - IBM               David Manchala - Xerox
   Angelo Caruso - Xerox            Carl-Uno Manros - Xerox
   Jeff Copeland - QMS              Jay Martin - Underscore
   Roger deBry - IBM                Larry Masinter - Xerox
   Lee Farrell - Canon              Ira McDonald - High North Inc.
   Sue Gleeson - Digital            Bob Pentecost - Hewlett-Packard
   Charles Gordon - Osicom          Patrick Powell - Astart
                                    Technologies
   Brian Grimshaw - Apple           Jeff Rackowitz - Intermec
   Jerry Hadsell - IBM              Xavier Riley - Xerox
   Richard Hart - Digital           Gary Roberts - Ricoh
   Tom Hastings - Xerox             Stuart Rowley - Kyocera
   Stephen Holmstead                Richard Schneider - Epson
   Zhi-Hong Huang - Zenographics    Shigern Ueda - Canon
   Scott Isaacson - Novell          Bob Von Andel - Allegro Software
   Rich Lomicka - Digital           William Wagner - Digital Products
   David Kellerman - Northlake      Jasper Wong - Xionics
   Software
   Robert Kline - TrueSpectra       Don Wright - Lexmark
   Dave Kuntz - Hewlett-Packard     Rick Yardumian - Xerox
   Takami Kurono - Brother          Lloyd Young - Lexmark
   Rich Landau - Digital            Peter Zehler - Xerox
   Greg LeClair - Epson             Frank Zhao - Panasonic
                                    Steve Zilles - Adobe























Herriot, et al.               Experimental                     [Page 24]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


9. Appendix A: Protocol Examples

9.1 Print-Job Request

   The following is an example of a Print-Job request with job-name,
   copies, and sides specified. The "ipp-attribute-fidelity" attribute
   is set to 'true' so that the print request will fail if the "copies"
   or the "sides" attribute are not supported or their values are not
   supported.

 Octets          Symbolic Value                Protocol field

 0x0100          1.0                           version-number
 0x0002          Print-Job                     operation-id
 0x00000001      1                             request-id
 0x01            start operation-attributes    operation-attributes-tag
 0x47            charset type                  value-tag
 0x0012                                        name-length
 attributes-     attributes-charset            name
 charset
 0x0008                                        value-length
 us-ascii        US-ASCII                      value
 0x48            natural-language type         value-tag
 0x001B                                        name-length
 attributes-     attributes-natural-language   name
 natural-
 language
 0x0005                                        value-length
 en-us           en-US                         value
 0x45            uri type                      value-tag
 0x000B                                        name-length
 printer-uri     printer-uri                   name
 0x001A                                        value-length
 http://forest:  printer pinetree              value
 631/pinetree
 0x42            nameWithoutLanguage type      value-tag
 0x0008                                        name-length
 job-name        job-name                      name
 0x0006                                        value-length
 foobar          foobar                        value
 0x22            boolean type                  value-tag
 0x16                                          name-length
 ipp-attribute-  ipp-attribute-fidelity        name
 fidelity
 0x01                                          value-length
 0x01            true                          value
 0x02            start job-attributes          job-attributes-tag
 0x21            integer type                  value-tag



Herriot, et al.               Experimental                     [Page 25]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 0x0006                                        name-length
 copies          copies                        name
 0x0004                                        value-length
 0x00000014      20                            value
 0x44            keyword type                  value-tag
 0x0005                                        name-length
 sides           sides                         name
 0x0013                                        value-length
 two-sided-      two-sided-long-edge           value
 long-edge
 0x03            end-of-attributes             end-of-attributes-tag
 %!PS...         <PostScript>                  data

9.2 Print-Job Response (successful)

   Here is an example of a successful Print-Job response to the previous
   Print-Job request.  The printer supported the "copies" and "sides"
   attributes and their supplied values.  The status code returned is '
   successful-ok'.

 Octets            Symbolic Value              Protocol field

 0x0100            1.0                         version-number
 0x0000            successful-ok               status-code
 0x00000001        1                           request-id
 0x01              start operation-attributes  operation-attributes-tag
 0x47              charset type                value-tag
 0x0012                                        name-length
 attributes-       attributes-charset          name
 charset
 0x0008                                        value-length
 us-ascii          US-ASCII                    value
 0x48              natural-language type       value-tag
 0x001B                                        name-length
 attributes-       attributes-natural-         name
 natural-language  language
 0x0005                                        value-length
 en-us             en-US                       value
 0x41              textWithoutLanguage type    value-tag
 0x000E                                        name-length
 status-message    status-message              name
 0x000D                                        value-length
 successful-ok     successful-ok               value
 0x02              start job-attributes        job-attributes-tag
 0x21              integer                     value-tag
 0x0006                                        name-length





Herriot, et al.               Experimental                     [Page 26]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 Octets            Symbolic Value              Protocol field

 job-id            job-id                      name
 0x0004                                        value-length
 147               147                         value
 0x45              uri type                    value-tag
 0x0007                                        name-length
 job-uri           job-uri                     name
 0x001E                                        value-length
 http://forest:63  job 123 on pinetree         value
 1/pinetree/123
 0x42              nameWithoutLanguage type    value-tag
 0x0009                                        name-length
 job-state         job-state                   name
 0x0004                                        value-length
 0x0003            pending                     value
 0x03              end-of-attributes           end-of-attributes-tag

9.3 Print-Job Response (failure)

   Here is an example of an unsuccessful Print-Job response to the
   previous Print-Job request. It fails because, in this case, the
   printer does not support the "sides" attribute and because the value
   '20' for the "copies" attribute is not supported. Therefore, no job
   is created, and neither a "job-id" nor a "job-uri" operation
   attribute is returned. The error code returned is 'client-error-
   attributes-or-values-not-supported' (0x040B).

 Octets        Symbolic Value                Protocol field

 0x0100        1.0                           version-number
 0x040B        client-error-attributes-or-   status-code
               values-not-supported
 0x00000001    1                             request-id
 0x01          start operation-attributes    operation-attribute tag
 0x47          charset type                  value-tag
 0x0012                                      name-length
 attributes-   attributes-charset            name
 charset
 0x0008                                      value-length
 us-ascii      US-ASCII                      value
 0x48          natural-language type         value-tag
 0x001B                                      name-length
 attributes-   attributes-natural-language   name
 natural-
 language
 0x0005                                      value-length




Herriot, et al.               Experimental                     [Page 27]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 Octets            Symbolic Value              Protocol field

 en-us         en-US                         value
 0x41          textWithoutLanguage type      value-tag
 0x000E                                      name-length
 status-       status-message                name
 message
 0x002F                                      value-length
 client-error- client-error-attributes-or-   value
 attributes-   values-not-supported
 or-values-
 not-supported
 0x05          start unsupported-attributes  unsupported-attributes tag
 0x21          integer type                  value-tag
 0x0006                                      name-length
 copies        copies                        name
 0x0004                                      value-length
 0x00000014    20                            value
 0x10          unsupported  (type)           value-tag
 0x0005                                      name-length
 sides         sides                         name
 0x0000                                      value-length
 0x03          end-of-attributes             end-of-attributes-tag

9.4 Print-Job Response (success with attributes ignored)

   Here is an example of a successful Print-Job response to a Print-Job
   request like the previous Print-Job request, except that the value of
   'ipp-attribute-fidelity' is false. The print request succeeds, even
   though, in this case, the printer supports neither the "sides"
   attribute nor the value '20' for the "copies" attribute. Therefore, a
   job is created, and both a "job-id" and a "job-uri" operation
   attribute are returned. The unsupported attributes are also returned
   in an Unsupported Attributes Group. The error code returned is '
   successful-ok-ignored-or-substituted-attributes' (0x0001).

 Octets            Symbolic Value              Protocol field

 0x0100            1.0                         version-number
 0x0001            successful-ok-ignored-or-   status-code
                   substituted-attributes
 0x00000001        1                           request-id
 0x01              start operation-attributes  operation-attributes-tag
 0x47              charset type                value-tag
 0x0012                                        name-length
 attributes-       attributes-charset          name
 charset
 0x0008                                        value-length



Herriot, et al.               Experimental                     [Page 28]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 Octets            Symbolic Value              Protocol field

 us-ascii          US-ASCII                    value
 0x48              natural-language type       value-tag
 0x001B                                        name-length
 attributes-       attributes-natural-         name
 natural-language  language
 0x0005                                        value-length
 en-us             en-US                       value
 0x41              textWithoutLanguage type    value-tag
 0x000E                                        name-length
 status-message    status-message              name
 0x002F                                        value-length
 successful-ok-    successful-ok-ignored-or-   value
 ignored-or-       substituted-attributes
 substituted-
 attributes
 0x05              start unsupported-          unsupported-attributes
                   attributes                  tag
 0x21              integer type                value-tag
 0x0006                                        name-length
 copies            copies                      name
 0x0004                                        value-length
 0x00000014        20                          value
 0x10              unsupported  (type)         value-tag
 0x0005                                        name-length
 sides             sides                       name
 0x0000                                        value-length
 0x02              start job-attributes        job-attributes-tag
 0x21              integer                     value-tag
 0x0006                                        name-length
 job-id            job-id                      name
 0x0004                                        value-length
 147               147                         value
 0x45              uri type                    value-tag
 0x0007                                        name-length
 job-uri           job-uri                     name
 0x001E                                        value-length
 http://forest:63  job 123 on pinetree         value
 1/pinetree/123
 0x42              nameWithoutLanguage type    value-tag
 0x0009                                        name-length
 job-state         job-state                   name
 0x0004                                        value-length
 0x0003            pending                     value
 0x03              end-of-attributes           end-of-attributes-tag





Herriot, et al.               Experimental                     [Page 29]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


9.5 Print-URI Request

   The following is an example of Print-URI request with copies and
   job-name parameters:

 Octets         Symbolic Value               Protocol field

 0x0100         1.0                          version-number

 Octets         Symbolic Value               Protocol field
 0x0003         Print-URI                    operation-id
 0x00000001     1                            request-id
 0x01           start operation-attributes   operation-attributes-tag
 0x47           charset type                 value-tag
 0x0012                                      name-length
 attributes-    attributes-charset           name
 charset
 0x0008                                      value-length
 us-ascii       US-ASCII                     value
 0x48           natural-language type        value-tag
 0x001B                                      name-length
 attributes-    attributes-natural-language  name
 natural-
 language
 0x0005                                      value-length
 en-us          en-US                        value
 0x45           uri type                     value-tag
 0x000B                                      name-length
 printer-uri    printer-uri                  name
 0x001A                                      value-length
 http://forest  printer pinetree             value
 :631/pinetree
 0x45           uri type                     value-tag
 0x000C                                      name-length
 document-uri   document-uri                 name
 0x11                                        value-length
 ftp://foo.com  ftp://foo.com/foo            value
 /foo
 0x42           nameWithoutLanguage type     value-tag
 0x0008                                      name-length
 job-name       job-name                     name
 0x0006                                      value-length
 foobar         foobar                       value
 0x02           start job-attributes         job-attributes-tag
 0x21           integer type                 value-tag
 0x0006                                      name-length
 copies         copies                       name
 0x0004                                      value-length



Herriot, et al.               Experimental                     [Page 30]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 0x00000001     1                            value
 0x03           end-of-attributes            end-of-attributes-tag

9.6 Create-Job Request

   The following is an example of Create-Job request with no parameters
   and no attributes:

 Octets         Symbolic Value              Protocol field
 0x0100         1.0                         version-number
 0x0005         Create-Job                  operation-id
 0x00000001     1                           request-id
 0x01           start operation-attributes  operation-attributes-tag
 0x47           charset type                value-tag
 0x0012                                     name-length

 Octets         Symbolic Value              Protocol field
 attributes-    attributes-charset          name
 charset
 0x0008                                     value-length
 us-ascii       US-ASCII                    value
 0x48           natural-language type       value-tag
 0x001B                                     name-length
 attributes-    attributes-natural-language name
 natural-
 language
 0x0005                                     value-length
 en-us          en-US                       value
 0x45           uri type                    value-tag
 0x000B                                     name-length
 printer-uri    printer-uri                 name
 0x001A                                     value-length
 http://forest: printer pinetree            value
 631/pinetree
 0x03           end-of-attributes           end-of-attributes-tag

9.7 Get-Jobs Request

   The following is an example of Get-Jobs request with parameters but
   no attributes:

 Octets           Symbolic Value               Protocol field

 0x0100           1.0                          version-number
 0x000A           Get-Jobs                     operation-id
 0x00000123       0x123                        request-id
 0x01             start operation-attributes   operation-attributes-tag
 0x47             charset type                 value-tag



Herriot, et al.               Experimental                     [Page 31]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 Octets           Symbolic Value               Protocol field

 0x0012                                        name-length
 attributes-      attributes-charset           name
 charset
 0x0008                                        value-length
 us-ascii         US-ASCII                     value
 0x48             natural-language type        value-tag
 0x001B                                        name-length
 attributes-      attributes-natural-language  name
 natural-
 language
 0x0005                                        value-length
 en-us            en-US                        value
 0x45             uri type                     value-tag
 0x000B                                        name-length
 printer-uri      printer-uri                  name
 0x001A                                        value-length
 http://forest:6  printer pinetree             value
 31/pinetree
 0x21             integer type                 value-tag
 0x0005                                        name-length
 limit            limit                        name
 0x0004                                        value-length
 0x00000032       50                           value
 0x44             keyword type                 value-tag
 0x0014                                        name-length
 requested-       requested-attributes         name
 attributes
 0x0006                                        value-length
 job-id           job-id                       value
 0x44             keyword type                 value-tag
 0x0000           additional value             name-length
 0x0008                                        value-length
 job-name         job-name                     value
 0x44             keyword type                 value-tag
 0x0000           additional value             name-length
 0x000F                                        value-length
 document-format  document-format              value
 0x03             end-of-attributes            end-of-attributes-tag

9.8 Get-Jobs Response

   The following is an of Get-Jobs response from previous request with 3
   jobs. The Printer returns no information about the second job
   (because of security reasons):





Herriot, et al.               Experimental                     [Page 32]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 Octets           Symbolic Value                Protocol field

 0x0100           1.0                           version-number
 0x0000           successful-ok                 status-code
 0x00000123       0x123                         request-id (echoed
                                                back)
 0x01             start operation-attributes    operation-attribute-tag
 0x47             charset type                  value-tag
 0x0012                                         name-length
 attributes-      attributes-charset            name
 charset
 0x000A                                         value-length
 ISO-8859-1       ISO-8859-1                    value
 0x48             natural-language type         value-tag
 0x001B                                         name-length
 attributes-      attributes-natural-language   name
 natural-
 language
 0x0005                                         value-length
 en-us            en-US                         value
 0x41             textWithoutLanguage type      value-tag
 0x000E                                         name-length
 status-message   status-message                name
 0x000D                                         value-length
 successful-ok    successful-ok                 value
 0x02             start job-attributes (1st     job-attributes-tag
                  object)
 0x21             integer type                  value-tag
 0x0006                                         name-length
 job-id           job-id                        name
 0x0004                                         value-length
 147              147                           value
 0x36             nameWithLanguage              value-tag
 0x0008                                         name-length
 job-name         job-name                      name
 0x000C                                         value-length
 0x0005                                         sub-value-length
 fr-ca            fr-CA                         value
 0x0003                                         sub-value-length
 fou              fou                           name
 0x02             start job-attributes (2nd     job-attributes-tag
                  object)
 0x02             start job-attributes (3rd     job-attributes-tag
                  object)
 0x21             integer type                  value-tag
 0x0006                                         name-length
 job-id           job-id                        name
 0x0004                                         value-length



Herriot, et al.               Experimental                     [Page 33]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


 Octets           Symbolic Value                Protocol field

 148              148                           value
 0x36             nameWithLanguage              value-tag
 0x0008                                         name-length
 job-name         job-name                      name
 0x0012                                         value-length
 0x0005                                         sub-value-length
 de-CH            de-CH                         value
 0x0009                                         sub-value-length
 isch guet        isch guet                     name
 0x03             end-of-attributes             end-of-attributes-tag







































Herriot, et al.               Experimental                     [Page 34]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


10. Appendix C: Registration of MIME Media Type Information for
    "application/ipp"

   This appendix contains the information that IANA requires for
   registering a MIME media type.  The information following this
   paragraph will be forwarded to IANA to register application/ipp whose
   contents are defined in Section 3 "Encoding of the Operation Layer"
   in this document:

   MIME type name: application

   MIME subtype name: ipp

   A Content-Type of "application/ipp" indicates an Internet Printing
   Protocol message body (request or response). Currently there is one
   version: IPP/1.0, whose syntax is described in Section 3 "Encoding of
   the Operation Layer" of [RFC2565], and whose semantics are described
   in [RFC2566].

   Required parameters:  none

   Optional parameters:  none

   Encoding considerations:

   IPP/1.0 protocol requests/responses MAY contain long lines and ALWAYS
   contain binary data (for example attribute value lengths).

   Security considerations:

   IPP/1.0 protocol requests/responses do not introduce any security
   risks not already inherent in the underlying transport protocols.
   Protocol mixed-version interworking rules in [RFC2566] as well as
   protocol encoding rules in [RFC2565] are complete and unambiguous.

   Interoperability considerations:

   IPP/1.0 requests (generated by clients) and responses (generated by
   servers) MUST comply with all conformance requirements imposed by the
   normative specifications [RFC2566] and [RFC2565]. Protocol encoding
   rules specified in [RFC2565] are comprehensive, so that
   interoperability between conforming implementations is guaranteed
   (although support for specific optional features is not ensured).
   Both the "charset" and "natural-language" of all IPP/1.0 attribute
   values which are a LOCALIZED-STRING  are explicit within IPP protocol
   requests/responses (without recourse to any external information in
   HTTP, SMTP, or other message transport headers).




Herriot, et al.               Experimental                     [Page 35]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


   Published specification:

   [RFC2566] Isaacson, S., deBry, R., Hastings, T., Herriot, R. and P.
             Powell, "Internet Printing Protocol/1.0: Model and
             Semantics" RFC 2566, April 1999.

   [RFC2565] Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet
             Printing Protocol/1.0: Encoding and Transport", RFC 2565,
             April 1999.

   Applications which use this media type:

   Internet Printing Protocol (IPP) print clients and print servers,
   communicating using HTTP/1.1 (see [RFC2565]), SMTP/ESMTP, FTP, or
   other transport protocol. Messages of type "application/ipp" are
   self-contained and transport-independent, including "charset" and
   "natural-language" context for any LOCALIZED-STRING value.

   Person & email address to contact for further information:

   Scott A. Isaacson
   Novell, Inc.
   122 E 1700 S
   Provo, UT 84606

   Phone: 801-861-7366
   Fax: 801-861-4025
   Email: sisaacson@novell.com

   or

   Robert Herriot (Editor)
   Xerox Corporation
   3400 Hillview Ave., Bldg #1
   Palo Alto, CA 94304

   Phone: 650-813-7696
   Fax:  650-813-6860
   EMail: rherriot@pahv.xerox.com












Herriot, et al.               Experimental                     [Page 36]
^L
RFC 2565            IPP/1.0: Encoding and Transport           April 1999


11.  Full Copyright Statement

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
























Herriot, et al.               Experimental                     [Page 37]
^L