path: root/doc/rfc/rfc2652.txt

Network Working Group                                          J. Allen
Request for Comments: 2652                         WebTV Networks, Inc.
Category: Standards Track                                   M. Mealling
                                                Network Solutions, Inc.
                                                            August 1999


     MIME Object Definitions for the Common Indexing Protocol (CIP)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

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

Abstract

   The Common Indexing Protocol (CIP) is used to pass indexing
   information from server to server in order to facilitate query
   routing. The protocol is comprised of several MIME objects being
   passed from server to server. This document describes the definitions
   of those objects as well as the methods and requirements needed to
   define a new index type.

1. Introduction

   The Common Indexing Protocol (CIP) is used to pass indexes between
   servers that combine multiple indexes and/or route queries based on
   those indexes. The overall framework for the protocol is specified in
   the CIP Framework document [FRAMEWORK]. This document should be read
   within the context of that document as there are fundamental concepts
   contained in the framework that are not fully explained here.

   Since there are several different ways to index a given database
   there will be multiple types of indexes to pass.  These indexes may
   have different transport requirements, different ways of specifying
   parameters, and different referral rules. These different
   requirements are handled by encapsulating the indexes within MIME
   wrappers in order to have a standardized way to specify those
   different parameters.





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   Appendix A contains the actual MIME [RFC2046] registration templates
   sent to the IANA for registration [RFC2048].

   This document uses language like SHOULD and SHALL that have special
   meaning as specified in "Key words for use in RFCs to Indicate
   Requirement Levels" [RFC2119].

2.0 CIP Transactions

   Messages passed by CIP implementations over reliable transport
   mechanisms fall into three categories: requests, responses and
   results. All requests result in either a response or a result. A
   result sent in response to a request must be interpreted as a
   successful operation.

   Requests, responses and results are formatted as MIME [RFC2046]
   messages. The specific MIME types involved are defined below.

   As with all MIME objects, CIP messages may be wrapped in a security
   multipart package to provide authentication and privacy. The security
   policy with respect to all messages is implementation defined, when
   not explicitly discussed below. CIP implementors are strongly urged
   to allow server administrators maximum configurability to secure
   their servers against maliciously sent anonymous CIP messages. In
   general, operations which can permanently change the server's state
   in a harmful way should only take place upon receipt of a properly
   signed message from a trusted CIP peer or administrator. Implementors
   should provide appropriate auditing capabilities so that both
   successful and failed requests can be tracked by the server
   administrator.

   Since these MIME objects can and will be sent over several different
   protocols, body termination is specified by the transfer protocol.
   New protocols are encouraged to use SMTP [RFC821] style body
   termination.

   Finally, since MIME objects can specify their own encoding, the
   line-breaks contained within each body are defined by the encoding.
   Thus, instead of specifying them as carriage-return and/or linefeed,
   the identifier <linebreak> is used. Linebreaks in the headers and
   separating the body from the headers follow existing standards.










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2.1 Common syntactic definitions

   There are certain syntactic elements common to all of the CIP
   transactions. These include type, DSI and the Base-URI.

2.1.1 The "application/index" MIME type tree

   Due to requirements in RFC2048 concerning objects that have the same
   type but different syntaxes, CIP objects will use the
   application/index tree but include "facets" [RFC2048] which extend it
   as other types have done with respect to global elements and vendor
   specific enhancements. Thus the tree is divided up into the following
   branches:

      application/index.cmd._command_
      application/index.response
      application/index.obj._type_
      application/index.vnd._xxx_

      _command_ is a command as specified here. It contains commands and
      their arguments.

      _type_ identifies what type of CIP index object is contained
      within the body. It is unique among all other reserved types.
      Reserved types are those previously documented by other CIP index
      object specifications, according to standard IETF processes.

      _xxx_ is an identifier specified by a vendor for use by that
      vendor in operations specifically to do with indexes.

   All of the above identifiers follow the rules in RFC2048 for valid
   MIME types. In addition commands, responses and types are limited by
   this document to consist of from 1 to 20 characters from the set [a-
   zA-Z0-9-]; that is, all upper and lower case letters, all digits, and
   the ASCII minus character (decimal 45). Though type names may be
   specified case sensitively, they must be compared and otherwise
   processed case insensitively.

   Appendix A contains the registration template for the
   application/index tree.

2.1.2 DSI

   A dataset identifier is an identifier chosen from any part of the
   ISO/CCITT OID space. The DSI uniquely identifies a given dataset
   among all datasets indexed by CIP.





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   As currently defined, OID's are an unbounded sequence of unbounded
   integers. While this creates an infinite numbering space, it presents
   problems for implementors dealing with machines with finite
   resources. To ease implementation, this document specifies an ASCII
   encoding of the OID, and specifies limits which make implementation
   easier.

   For the purposes of interchange in CIP messages, an OID must conform
   to the following rules:

      dsi          = integer *( "." integer)
      integer      = all-digits / (one-to-nine *all-digits)
      one-to-nine  = "1" / "2" / "3" / "4" / "5" / "6" / "7" /
                     "8" / "9"
      all-digits   = "0" / one-to-nine

   Under no circumstances shall the total length of the resulting string
   exceed 255 characters. OID's which cannot, due to their length,
   conform to these rules must not be used as CIP dataset identifiers.

   An implementation must not attempt to parse the individual integers
   unless it is prepared to handle arbitrary-length integers. Treating
   the DSI as anything other than an opaque string of US-ASCII
   characters is not recommended.

   Two CIP DSI's are considered to match if both conform to the above
   rules and every number matches.

2.1.3. Base-URI

   CIP index objects carry base-URI's to facilitate referral generation
   based on the index object. The base-URI parameter carries a
   whitespace-delimited list of URL's. URL's are defined in RFC-1738.
   The exact rules are as follows:

      base-uri    = genericurl *( 1*whitespace genericurl )
      whitespace  = "<space>" (decimal 32) /
                    "<tab>"   (decimal 9)  /
                    "<cr>"    (decimal 13) /
                    "<lf>"    (decimal 10)
      genericurl = { as specified in RFC-1738, section 5 }

2.2 Response format

   All requests must be followed by a response code, except in the cases
   where a return path is unavailable.

   The definition for this MIME type is:



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      MIME type name:          application
      MIME subtype name:       index.response
      Required parameters:      code
      Optional parameters:     charset
      Security considerations: (See Section 4)

   The code parameter contains a 3 digit return code that denotes the
   status of the last command.

   The format of the body is such that the first line is interpreted as
   the comment corresponding to the code. As with most response codes
   this comment is intended for human consumption and may not exist and
   must not be depended on by the protocol. Subsequent lines in the body
   are reserved for each response to define.  In the case where the
   comment is not given the first must be an empty line.

      body = comment linebreak payload
      comment = { any text }
      linebreak = (decimal 13) (decimal 10)
      payload = { any text }

   The charset parameter has its normal MIME meaning. Below are several
   examples:

   [begin MIME]
   Content-type: application/index.response; code=220

   CIP Server v1.0 ready!<linebreak>
   [end MIME]

   [begin MIME]
   Content-type: application/index.response; code=500

   MIME formatting problem<linebreak>
   [end MIME]

   [begin MIME]
   Content-type: application/index.response; code=520

   <linebreak>
   [end MIME]

   While the responses described in this document do not utilize the
   rest of the lines in the body of a response implementors should take
   care to not disallow it in the future. A good example would be a
   message specifying that a poll request did not contain required
   attributes. This message might look like this:




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   [begin MIME]
   Content-type: application/index.response; code=502

   Request is missing required CIP attributes
   Missing-Attribute: attribute1
   Missing-Attribute: attribute2
   Missing-Attribute: attribute3
   [end MIME]

   The meaning of the various digits in the response codes is discussed
   in RFC-821, Appendix E.

   See Appendix B for a list of the valid response codes.

2.3 Command format

   A CIP command either initiates an index transfer, interrogates the
   state of the receiver-CIP (or the server's participation in the
   mesh), or changes the state of the server (or the server's place in
   the mesh).

   CIP commands are sent as a MIME message of type
   "application/index.cmd._command_". The definition for this MIME type
   tree follows:

      MIME type name:          application
      MIME subtype name:       index.cmd._command_
      Optional parameters:     type, dsi
      Security considerations: (See Section 4)

   The format of the body is defined by each command. A general
   attribute/value pair orientation is preserved throughout the
   following specified commands. Those developing future command should
   attempt to maintain that orientation but are not required to do so.

   In the following sections, the server's response for each possible
   value for "command" is defined. Note that the parameters listed as
   optional above are only optional with respect to the generic MIME
   form. The optional parameters are only optional with respect to MIME
   parsing. If one or more of the parameters needed to fulfill a command
   is missing, a response code of 502 is returned.

   Extra optional parameters which are unrecognized must be silently
   ignored.







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2.3.1 No-operation

      Command Name:        application/index.cmd.noop
      Required parameters: (none)

   A CIP command with the "command" parameter set to "noop" must be
   acknowledged with response type code 200 (command OK, no response
   forthcoming).

   This command must not require a signed MIME object. Implementations
   should accept commands which have been validly signed.

   Example:

   [begin MIME]
   Content-type: application/index.cmd.noop

   [end MIME]

   Note the lack of a body but how the <linebreak> pair is still
   preserved after the Content-type header.

2.3.2 Poll

      Request Name:        application/index.cmd.poll
      Required parameters: type, dsi

   The "poll" command is used by a poller to request the transfer of an
   index object. It requires the following parameters:

      type:      The index object type requested
      dsi:       The dataset which the index should cover

   If there are no index objects available for a given DSI, or the
   receiver-CIP does not support a given index object type, the
   receiver-CIP must respond with response code 200, (successful, no
   response forthcoming).  Otherwise, the response code must be 201
   (successful, response is forthcoming).

   The security policy for polling commands is wholly implementation
   defined. Implementations may be configured to accept or reject
   anonymous poll commands.

   Example:

   [begin MIME]
   Content-type: application/index.cmd.poll; type="simple";
           dsi= "1.3.5.7.9"



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   Template: contact name address phone<linebreak>
   Start-time: Fri May 30 14:25:30 EDT 1997<linebreak>
   End-time: Sat May 31 14:25:30 EDT 1997<linebreak>
   [end MIME]

2.3.3 DataChanged

      Request Name:        application/index.cmd.datachanged
      Required parameters: type, dsi

   The "datachanged" command is used by a pollee to notify a poller that
   the data within an index has changed. It requires the following
   parameters:

      type:      The index object type requested
      dsi:       The dataset which the index should cover

   If there are no index objects available for a given DSI, or the
   receiver-CIP does not support a given index object type, the
   receiver-CIP must respond with response code 200, (successful, no
   response forthcoming).  Otherwise, the response code must be 201
   (successful, response is forthcoming).

   The body of a DataChanged command is formatted as a simple set of
   attribute value pairs following the rules of RFC822. The actual
   attributes and values allowed are defined by the index type
   specification.

   The security policy for DataChanged commands is wholly implementation
   defined. Implementations may be configured to accept or reject
   anonymous DataChanged commands.

   Example:

   [begin MIME]
   Content-type: application/index.cmd.datachanged;
           type="simple"; dsi= "1.3.5.7.9"<linebreak>

   Time-of-latest-change: Fri May 30 14:25:30 EDT 1997<linebreak>
   Time-of-message-generation: Fri May 30 14:25:30 EDT 1997<linebreak>
   Host-Name: cip.rwhois.net<linebreak>
   Host-Port: 4322<linebreak>
   Protocol: RWhois2.0<linebreak>
   [end MIME]







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2.3.4 Additional Requests

   The requests specified above are those required to implement a simple
   mesh. It is expected that other requests will be developed to handle
   issues of mesh-management and statistics gathering requests. At this
   point this is an area of additional work. Specifically more work is
   needed in the area of mesh management as meshes will tend to be
   organized around the characteristics of their index type.

2.4. Index Object format

   In reply to the "poll" command, a server may choose to send one or
   more index objects. Regardless of the number of index objects
   returned, the response must take the form of a MIME multipart/mixed
   message. Each part must itself be a MIME object of type
   "application/index.obj._type_". The definition for this type follows:

      MIME type name:          application
      MIME subtype name:       index.obj._type_
      Required parameters:     dsi, base-uri
      Optional parameters:     none
      Security considerations: (See Section 4)

      As previously described, each index object is of a particular
      type.  This type is specified in the MIME subtype name since some
      types may have a different syntax.

      The required parameters are to be used as follows:

      DSI:       The DSI is a string which globally uniquely identifies
                 the dataset from which the index was created.

      base-URI:  One or more URI's will form the base of any referrals
                 created based upon this index object.

3. Index Type Definition Requirements

   Because of the need for application domain specific indices, CIP
   index objects are abstract; they must be defined by a separate
   specification. The basic protocols for moving index objects are
   widely applicable, but the specific design of the index, and the
   structure of the mesh of servers which pass a particular type of
   index is dependent on the application domain. While companion
   documents will describe index objects, there is a set of base
   requirements and questions those documents must address. This is to
   ensure that the base assumptions that the CIP protocol makes about
   its indexes are actually expressible within the index.




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   Since each type is a MIME type all its own, registration of new types
   follows the standard registration policies specified in RFC2048.

3.1 Type specific requests

   Any index type definition must address the type specific bodies of
   the Poll and DataChanged requests. All parameters included in the
   body must be specified.

3.2 The index.obj parameters

3.2.1 Type

   See the above definitions for allowed values for type.

   A new name must be assigned when any changes to the document
   describing the index object type are not completely backwards
   compatible.

3.2.2 DSI

   Another attribute is the "DSI", or Dataset Identifier, which uniquely
   identifies the dataset from which the index was created. The index
   specification should define the policies for how the DSI is
   generated. This includes the concept of what a data-set means for the
   given index.

3.2.3. Base-URI

   An attribute of the index object which is crucial for generating
   referrals is the "Base-URI". The URI (or URI's) contained in this
   attribute form the basis of any referrals generated based on this
   index block. The URI is also used as input during the index
   aggregation process to constrain the possible types of aggregation.
   This use of the Base-URI is used to deal with meshes that support
   multiple protocols.

   Thus, an index specification should define how the Base-URI applies
   to the underlying index and how it is changed during the aggregation
   process.











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3.3 Aggregation

   All index object specifications must address the issue of
   aggregation.  This is the method by which an index server takes two
   or more indexes and combines them into one index to be passed on. It
   is not required that a given index-type aggregate. If it does not it
   must explicitly address the reasons why and what affect that has on
   scalability.

   If a given index does aggregate, the algorithm for that aggregation
   must be given. It must also address how that algorithm affects mesh
   organization and scalability.

   Index object document authors should remember that any kind of
   aggregation should be performed without compromising the ability to
   correctly route queries while avoiding excessive numbers of missed
   results. The acceptable likelihood of false negatives must be
   established on a per-application-domain basis, and is controlled by
   the granularity of the index and the aggregation rules defined for it
   by the particular specification.

   Nothing in these documents specifically disallows aggregation rules
   that deal with different index object types. This type of
   heterogeneous mesh is difficult to formulate at best and thus is not
   covered by these documents. If document authors wish to attempt such
   a mesh they should be aware that it is considered an ill understood
   concept that contains many pitfalls for the mesh builder.

3.4 Referral Generation Semantics

   Since the method by which a client navigates the mesh is by
   referrals, the document must address how a given access protocol
   generates a referral from the index. Authors should pay particular
   attention to the case where an index is accessed by different
   protocols and the interaction between them. For example, an index
   that supports referrals being generated for both RWhois and LDAP must
   understand that one uses a Distinguished Name while the other
   doesn't. The impacts of these differences on the referral should be
   clear.

3.5 Matching Semantics

   In order to generate a referral the decision of whether or not to do
   so must be handled by the access protocol. The semantics surrounding
   this decision have a large impact on the efficiency of searches as
   well as the requirements on aggregation. Thus, index specification
   authors must be very clear about how a match is determined.




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3.6 Security Considerations

   As is customary with Internet protocol documentation, a brief review
   of security implications of the proposed object must be included.
   This section may need to do little more than echo the considerations
   expressed in this document's Security Considerations section.

3.7 Optional Coverage

   Because indexing algorithms, stop-lists, and data reduction
   technologies are considered by some index object designers to be
   proprietary, it is not necessary to discuss the process used to
   derive indexing information from a body of source material. When
   proprietary indexing technologies are used in a public mesh, all CIP
   servers in the mesh should be able to parse the index object (and
   perform aggregation operations, if necessary), though not all of them
   need to be able to create these proprietary indices from source data.

   Thus, index object designers may choose to remain silent on the
   algorithms used for the generation of indices, as long as they
   adequately document how to participate in a mesh of servers passing
   these proprietary indices.

   Designers should also seriously consider including useful examples of
   source data, the generated index, and the expected results from
   example matches. When the aggregation algorithm is complex, it is
   recommended that a table showing two indices and the resultant
   aggregate index be included.

4. Security Considerations

   Security considerations come into play in at least the following two
   scenarios.  Indexing information can leak undesirable amounts of
   proprietary information, unless carefully controlled. At a more
   fundamental level, the CIP protocol itself requires external security
   services to operate in a safe manner. Both topics are covered below.

4.1 Secure Indexing

   CIP is designed to index all kinds of data. Some of this data might
   be considered valuable, proprietary, or even highly sensitive by the
   data maintainer. Take, for example, a human resources database.
   Certain bits of data, in moderation, can be very helpful for a
   company to make public. However, the database in its entirety is a
   very valuable asset, which the company must protect. Much experience
   has been gained in the directory service community over the years as
   to how best to walk this fine line between completely revealing the
   database and making useful pieces of it available.



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   Another example where security becomes a problem is for a data
   publisher who would like to participate in a CIP mesh. The data that
   publisher creates and manages is the prime asset of the company.
   There is a financial incentive to participate in a CIP mesh, since
   exporting indices of the data will make it more likely that people
   will search your database. (Making profit off of the search activity
   is left as an exercise to the entrepreneur.) Once again, the index
   must be designed carefully to protect the database while providing a
   useful synopsis of the data.

   One of the basic premises of CIP is that data providers will be
   willing to provide indices of their data to peer indexing servers.
   Unless they are carefully constructed, these indices could constitute
   a threat to the security of the database. Thus, security of the data
   must be a prime consideration when developing a new index object
   type. The risk of reverse engineering a database based only on the
   index exported from it must be kept to a level consistent with the
   value of the data and the need for fine-grained indexing.

   Since CIP is encoded as MIME objects, MIME security solutions should
   be used whenever possible. Specifically when dealing with security
   between index servers.

4.2 Protocol Security

   CIP protocol exchanges, taking the form of MIME messages, can be
   secured using any technology available for securing MIME objects. In
   particular, use of RFC-1847's Security Multiparts are recommended.  A
   solid application of RFC-1847 using widely available encryption
   software is PGP/MIME, RFC-2016. Implementors are encouraged to
   support PGP/MIME, as it is the first viable application of the MIME
   Security Multiparts architecture. As other technologies become
   available, they may be incorporated into the CIP mesh.

   If an incoming request does not have a valid signature, it must be
   considered anonymous for the purposes of access control. Servers may
   choose to allow certain requests from anonymous peers, especially
   when the request cannot cause permanent damage to the local server.
   In particular, answering anonymous poll requests encourages index
   builders to poll a server, making the server's resources better
   known.

   The explicit security policy with respect to incoming requests is
   outside the scope of this specification. Implementors are free to
   accept or reject any request based on the security attributes of the
   incoming message. When a request is rejected due to authentication
   reasons, a response code from the 530 series must be issued.




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Acknowledgments

   Thanks to the many helpful members of the FIND working group for
   discussions leading to this specification.

   Specific acknowledgment is given to Jeff Allen formerly of Bunyip
   Information Systems. His original version of these documents helped
   enormously in crystallizing the debate and consensus. Most of the
   actual text in this document was originally authored by Jeff.

Authors' Addresses

   Jeff R. Allen
   246 Hawthorne St.
   Palo Alto, CA 94301

   EMail: jeff.allen@acm.org


   Michael Mealling
   Network Solutions, Inc.
   505 Huntmar Park Drive
   Herndon, VA 22070

   Phone: +1-703-742-0400
   EMail: michael.mealling@RWhois.net

References

   [FRAMEWORK]  Allen, J. and M. Mealling, "The Architecture of the
                Common Indexing Protocol (CIP)", RFC 2651, August 1999.

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

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

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

   [RFC821]     Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC
                821, August 1992.






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Appendix A: Media Type Registration Templates

   The following templates have been registered with the IANA:

Index tree

   To: ietf-types@iana.org
   Subject: Registration of MIME media type tree application/index

   MIME media type name: application

   MIME subtype name: index

   Required parameters: none

   Optional parameters: none

   Encoding considerations: none

   Security considerations:

      Security considerations come into play in at least the following
      two scenarios.  Indexing information can leak undesirable amounts
      of proprietary information, unless carefully controlled. At a more
      fundamental level, the CIP protocol itself requires external
      security services to operate in a safe manner. Both topics are
      covered below.

   Interoperability considerations:

   Published specification:

      RFC 2652

   Applications which use this media type:

      This media type is used to contain information about indices and
      how they inter-operate to form meshes of index servers.

   Additional information:

      This media type is not a standalone type. It is the top level of a
      tree similar to the vnd or prs trees specified in Section 2.1 of
      RFC2048. There are four specified branches to this tree:
            application/index.cmd
            application/index.response
            application/index.obj
            application/index.vnd



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      Each of these branches is a tree in its own right with types
      registered below them. See those registrations for more
      information on the types allowed below those branches.


   Person & email address to contact for further information:

   Intended usage: LIMITED USE

   Author/Change controller:

Command tree

   To: ietf-types@iana.org
   Subject: Registration of MIME media type application/index.cmd

   MIME media type name: application

   MIME subtype name: index.cmd

   Required parameters: none

   Optional parameters: none

   Encoding considerations: none

   Security considerations:

      Security considerations come into play in at least the following
      two scenarios.  Indexing information can leak undesirable amounts
      of proprietary information, unless carefully controlled. At a more
      fundamental level, the CIP protocol itself requires external
      security services to operate in a safe manner. Both topics are
      covered below.

   Interoperability considerations:

      Implementors should handle unknown commands gracefully.

   Published specification:

      RFC 2652









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   Applications which use this media type:

      This media type is the top of a tree of media types that express
      commands between hosts that exchange indices for the purpose of
      routing referrals.

   Additional information:

      This media type is not a standalone type. It is the top of a tree
      similar to the vnd and prs trees specified in Section 2.1 of
      RFC2048. Types registered within this tree are limited to being
      commands as specified in the document(s) referenced in the
      "Published specifications" section.

   Person & email address to contact for further information:

   Intended usage: LIMITED USE

   Author/Change controller:

Response tree

   To: ietf-types@iana.org
   Subject: Registration of MIME media type application/index.response

   MIME media type name: application

   MIME subtype name: index.response

   Required parameters: code

   Optional parameters: none

   Encoding considerations: none

   Security considerations:

      Security considerations come into play in at least the following
      two scenarios.  Indexing information can leak undesirable amounts
      of proprietary information, unless carefully controlled. At a more
      fundamental level, the CIP protocol itself requires external
      security services to operate in a safe manner. Both topics are
      covered below.

   Interoperability considerations:

      Implementors should handle unknown responses gracefully.




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RFC 2652               MIME Definitions for CIP              August 1999


   Published specification:

      RFC 2652

   Applications which use this media type:

      This media type is used to encode responses to CIP commands passed
      between hosts that exchange indices for the purpose of routing
      referrals.

   Additional information:

      This media type _is_ a standalone type. The code parameter
      contains the specific response code as specified by Appendix B of
      the specification document.

   Person & email address to contact for further information:

   Intended usage: LIMITED USE

   Author/Change controller:

Index Object tree

   To: ietf-types@iana.org
   Subject: Registration of MIME media type application/index.obj

   MIME media type name: application

   MIME subtype name: index.obj

   Required parameters: type, dsi, base-uri

   Optional parameters: none

   Encoding considerations: none

   Security considerations:

      Security considerations come into play in at least the following
      two scenarios.  Indexing information can leak undesirable amounts
      of proprietary information, unless carefully controlled. At a more
      fundamental level, the CIP protocol itself requires external
      security services to operate in a safe manner. Both topics are
      covered below.






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RFC 2652               MIME Definitions for CIP              August 1999


   Interoperability considerations:

      Implementors should handle unknown index objects according to
      rules specified in the published specification.

   Published specification:

      RFC 2652

   Applications which use this media type:

      This media type is the top of a tree of media types that express
      indexes that are exchanged between hosts that operate within a
      referral mesh.

   Additional information:

      This media type is not a standalone type. It is the top of a tree
      similar to the vnd and prs trees specified in Section 2.1 of
      RFC2048. Types registered within this tree are limited to being
      representations of indexes that contain some summary of the data
      found in some database and is used to generate referrals as
      specified in the above specified publication.

   Person & email address to contact for further information:

   Intended usage: LIMITED USE

   Author/Change controller:

Vendor tree

   To: ietf-types@iana.org
   Subject: Registration of MIME media type application/index.vnd

   MIME media type name: application

   MIME subtype name: index.vnd

   Required parameters: none

   Optional parameters: none

   Encoding considerations: none







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RFC 2652               MIME Definitions for CIP              August 1999


   Security considerations:

      Security considerations come into play in at least the following
      two scenarios.  Indexing information can leak undesirable amounts
      of proprietary information, unless carefully controlled. At a more
      fundamental level, the CIP protocol itself requires external
      security services to operate in a safe manner. Both topics are
      covered below.

   Interoperability considerations:

      Implementors should handle unknown objects gracefully.

   Published specification:

      RFC 2652

   Applications which use this media type:

      This media type is the top of a tree of media types that express
      vendor specific extensions to the framework specified in the
      published specifications.

   Additional information:

      This media type is not a standalone type. It is the top of a tree
      similar to the vnd and prs trees specified in Section 2.1 of
      RFC2048. Types registered within this tree are limited to being
      vendor specific extensions to the CIP framework as specified in
      the publications. Any registrations within this tree are still
      limited to dealing with indexes, meshes and referrals.

   Person & email address to contact for further information:

   Intended usage: LIMITED USE

Appendix B: Response Codes

   The meaning of the various digits in the response codes is discussed
   in RFC-821, Appendix E.

   The following response codes are defined for use by CIPv3 servers.
   Implementors must use these exact codes; undefined codes should be
   interpreted by CIP servers as fatal protocol errors.  Instead of
   defining new codes for unforeseen situations, implementors must adapt
   one of the given codes. The implementation should attach a useful
   alternative comment to the reused response code.




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RFC 2652               MIME Definitions for CIP              August 1999


      Code    Suggested description text
              Sender-CIP action
      --------------------------------------------------------
      220     Initial server banner message

      300     Requested CIP version accepted
              Continue with CIP transaction, in the specified
              version.

      222     Connection closing (in response to sender-CIP close)
              Done with transaction.

      200     MIME request received and processed
              Expect no output, continue session (or close)

      201     MIME request received and processed, output follows
              Read a response, delimited by SMTP-style message
              delimiter.

      400     Temporarily unable to process request
              Retry at a later time. May be used to indicate
              that the server does not currently have the
              resources available to accept an index.

      500     Bad MIME message format
              Retry with correctly formatted MIME request.

      501     Unknown or missing request in application/index.cmd
              Retry with correct CIP command.

      502     Request is missing required CIP attributes
              Retry with correct CIP attributes.

      520     Aborting connection for some unexpected reason
              Retry and/or alert local administrator.

      530     Request requires valid signature
              Sign the request, if possible, and retry.
              Otherwise, report problem to the administrator.

      531     Request has invalid signature
              Report problem to the administrator.


      532     Cannot check signature
              Alert local administrator, who should cooperate with
              remote administrator to diagnose and resolve the
              problem. (Probably missing a public key.)



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RFC 2652               MIME Definitions for CIP              August 1999


5.  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.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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