Network Working Group                                     P. Saint-Andre
Request for Comments: 4854                                           XSF
Category: Informational                                       April 2007


             A Uniform Resource Name (URN) Namespace for
 Extensions to the Extensible Messaging and Presence Protocol (XMPP)

Status of This Memo

  This memo provides information for the Internet community.  It does
  not specify an Internet standard of any kind.  Distribution of this
  memo is unlimited.

Copyright Notice

  Copyright (C) The IETF Trust (2007).

Abstract

  This document describes a Uniform Resource Name (URN) namespace for
  uniquely identifying Extensible Markup Language (XML) formats and
  protocols that provide extensions to the Extensible Messaging and
  Presence Protocol (XMPP) and are defined in specifications published
  by the XMPP Standards Foundation (XSF).


























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Table of Contents

  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
  2.  Specification Template  . . . . . . . . . . . . . . . . . . . . 3
  3.  Namespace Considerations  . . . . . . . . . . . . . . . . . . . 6
  4.  Community Considerations  . . . . . . . . . . . . . . . . . . . 6
  5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
  6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
  7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8
    7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 8
    7.2.  Informative References  . . . . . . . . . . . . . . . . . . 8








































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1.  Introduction

  While the Extensible Messaging and Presence Protocol (XMPP), as
  specified in [XMPP-CORE] and [XMPP-IM], provides basic messaging and
  presence functionality, the fact that XMPP is at root a technology
  for streaming Extensible Markup Language [XML] data makes it possible
  to include virtually any structured information within XMPP, as long
  as such information is qualified by appropriate XML namespaces
  [XML-NAMES].  When sent over XMPP, such structured data formats and
  protocols are generally referred to as "XMPP extensions".

  A large number of such XMPP extensions exist.  The main standards
  development organization in which such extensions are defined is the
  XMPP Standards Foundation (XSF) (formerly the Jabber Software
  Foundation), which contributed XMPP to the Internet Standards
  process.  Typically, such extensions are defined within the XSF's
  XMPP Extension Protocol (XEP) specification series.  To date, the XML
  namespaces defined within the Jabber/XMPP community have used names
  of the form "jabber:*" (deprecated since early 2002) and
  "http://jabber.org/protocol/*" (not including names of the form
  "urn:ietf:params:xml:ns:xmpp-*" specified in the XMPP RFCs).
  However, it is desirable that names associated with future XMPP
  extensions be both unique and persistent, which is not necessarily
  the case with names that are also HTTP URLs.  Therefore, in
  accordance with the process defined in [MECHANISMS], this document
  registers a formal namespace identifier (NID) for Uniform Resource
  Names [URN] associated with XMPP extensions published in the XSF's
  XEP series and for XML namespaces registered with the XSF's XMPP
  Registrar function [REGISTRAR].

2.  Specification Template

  Namespace ID:

     The Namespace ID "xmpp" is requested.

  Registration Information:

     Version 1
     Date: 2007-04-27

  Declared Registrant of the Namespace:

     Registering organization
        Organization: XMPP Standards Foundation
        Address: P.O. Box 1641, Denver, CO 80201 USA





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     Designated contact
        Role: XMPP Registrar
        Email: [email protected]

  Declaration of Syntactic Structure:

     The Namespace Specific String (NSS) of all URNs that use the
     "xmpp" NID shall have the following structure:

        urn:xmpp:{ShortName}:{SubName}

     The keywords have the following meaning:

        (1) the "ShortName" is a required US-ASCII string that
        conforms to the URN syntax requirements (see RFC 2141)
        and defines a particular protocol or format that is used
        as an XMPP extension.

        (2) the "SubName" is an optional US-ASCII string that
        conforms to the URN syntax requirements (see RFC 2141)
        and defines a particular subset of the relevant protocol
        or format.

     The XSF's XMPP Registrar function shall be responsible for
     managing the assignment of both "ShortName" and "SubName"
     strings and maintaining a registry of resulting namespaces
     at <http://www.xmpp.org/registrar/namespaces.html>.  The
     XMPP Registrar may also assign URNs in sub-trees below the
     level of the ShortName or SubName as needed for use in various
     XMPP extensions.

  Relevant Ancillary Documentation:

     Information about the XSF's XMPP Registrar function can be
     found at <http://www.xmpp.org/extensions/xep-0053.html>
     and <http://www.xmpp.org/registrar/>.

  Identifier Uniqueness Considerations:

     The XMPP Registrar is already responsible for managing
     the assignment of XML namespace names of the form
     "http://jabber.org/protocol/{ShortName}" and
     "http://jabber.org/protocol/{ShortName}#{SubName}"
     (e.g., "http://jabber.org/protocol/pubsub" and
     "http://jabber.org/protocol/disco#info").  In order to
     assign namespace names in the context of the "xmpp"
     NID, the XMPP Registrar shall simply modify the syntax
     of the namespace names it assigns from



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     "http://jabber.org/protocol/{ShortName}" and
     "http://jabber.org/protocol/{ShortName}#{SubName}" to
     "urn:xmpp:{ShortName}" and "urn:xmpp:{ShortName}:{SubName}".

     The XMPP Registrar shall ensure the uniqueness of all
     XMPP URNs by checking such names against the list of
     existing namespace names, as documented in XEP-0053
     (the controlling specification for the XMPP Registrar
     function).  The XMPP Registrar shall, in all cases, directly
     ensure the uniqueness of the assigned strings and shall
     not assign secondary responsibility for management of any
     sub-trees.  However, the XMPP Registrar may assign URNs
     in sub-trees below the level of the ShortName or SubName
     as needed for use in various XMPP extensions.  The
     resulting URNs shall not be re-assigned.

  Identifier Persistence Considerations:

     The XMPP Registrar shall provide clear documentation of
     the registered uses of the "xmpp" NID in the form of
     XMPP Extension Protocol (XEP) specifications published
     at <http://www.xmpp.org/extensions/>, as well as a
     registry of the namespace names themselves at
     <http://www.xmpp.org/registrar/namespaces.html>.

  Process of Identifier Assignment:

     The XMPP Registrar's processes and procedures for
     identifier assignment are documented in XEP-0053,
     which is the controlling specification for the XMPP
     Registrar function.  In particular, identifiers shall
     be issued only upon advancement of the relevant protocol
     specification to a status of Draft within the standards
     process, followed by the XMPP Standards Foundation (as
     specified in XEP-0001).  The XMPP Registrar shall check
     all identifiers against the list of existing namespace
     names to ensure uniqueness and to encourage relevance
     and memorability.  Assignment of URNs within the "xmpp"
     tree is reserved to the XMPP Standards Foundation,
     specifically to its XMPP Registrar function.

  Process for Identifier Resolution:

     The namespace is not currently listed with a Resolution
     Discovery System (RDS), but nothing about the namespace
     prohibits the future definition of appropriate resolution
     methods or listing with an RDS.




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  Rules for Lexical Equivalence:

     No special considerations; the rules for lexical
     equivalence specified in RFC 2141 apply.

  Conformance with URN Syntax:

     No special considerations.

  Validation Mechanism:

     None specified.

  Scope:

     Global.

3.  Namespace Considerations

  The XMPP Standards Foundation has been developing Internet protocols
  since August 2001 and that work is expected to continue for the
  foreseeable future.  The old-style "jabber:*" namespace names
  originally used in the Jabber open-source community were not proper
  URNs or URIs and thus were deprecated in early 2002.  Since then, the
  namespace names assigned by the XMPP Registrar function of the XMPP
  Standards Foundation have been (equivalent to) specialized HTTP URLs
  whose authority component is "jabber.org".  While that domain is
  currently under the control of the XMPP Standards Foundation, there
  is no guarantee that it will always remain so, thus potentially
  threatening the reliability and permanence of the assigned namespace
  names.  The use of Uniform Resource Names with an appropriate
  Namespace ID will enable the XMPP Standards Foundation to assign
  cleaner, more general, more permanent, more reliable, and more
  controllable namespace names related to the XMPP extensions it
  defines, while keeping the tree of XMPP extensions produced by the
  XMPP Standards Foundation properly separate from the IETF tree used
  to define some of the core XMPP namespaces as well as namespaces
  related to XMPP extensions that may be produced in the future by the
  IETF.

4.  Community Considerations

  The XMPP standards development community will benefit from
  publication of this namespace by having more permanent and reliable
  names for the XML namespaces defined in XMPP Extension Protocol
  specifications produced by the XMPP Standards Foundation.





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  The standards process followed by the XSF is open to contributions
  from any interested individual; such a contribution takes the form of
  a proposal submitted to the XMPP Extensions Editor
  <mailto:[email protected]>, accepted by the XMPP Council
  <http://www.xmpp.org/council/>, and published in the XSF's XMPP
  Extension Protocol (XEP) series at <http://www.xmpp.org/extensions/>.
  Use of the proposed space for a particular XML format or protocol
  extension will be contingent upon advancement of the appropriate
  specification within the XSF's standards process (as documented in
  [XEP]) and issuance of a namespace name within the "xmpp" tree by the
  XMPP Registrar (as documented in [REGISTRAR]).

5.  Security Considerations

  This document introduces no additional security considerations beyond
  those associated with the use and resolution of URNs in general.

6.  IANA Considerations

  This document defines a URN NID registration of "xmpp", which has
  been entered into the IANA registry located at
  <http://www.iana.org/assignments/urn-namespaces>.





























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7.  References

7.1.  Normative References

  [MECHANISMS]  Daigle, L., van Gulik, D., Iannella, R., and P.
                Faltstrom, "Uniform Resource Names (URN) Namespace
                Definition Mechanisms", BCP 66, RFC 3406, October 2002.

  [URN]         Moats, R., "URN Syntax", RFC 2141, May 1997.

7.2.  Informative References

  [REGISTRAR]   Saint-Andre, P., "XMPP Registrar Function", XSF
                XEP 0053, December 2006.

  [XEP]         Saint-Andre, P., "XMPP Extension Protocols", XSF
                XEP 0001, December 2006.

  [XML]         Bray, T., Paoli, J., Sperberg-McQueen, C., and E.
                Maler, "Extensible Markup Language (XML) 1.0 (2nd ed)",
                W3C REC-xml, October 2000,
                <http://www.w3.org/TR/REC-xml>.

  [XML-NAMES]   Bray, T., Hollander, D., and A. Layman, "Namespaces in
                XML", W3C REC-xml-names, January 1999,
                <http://www.w3.org/TR/REC-xml-names>.

  [XMPP-CORE]   Saint-Andre, P., "Extensible Messaging and Presence
                Protocol (XMPP): Core", RFC 3920, October 2004.

  [XMPP-IM]     Saint-Andre, P., "Extensible Messaging and Presence
                Protocol (XMPP): Instant Messaging and Presence",
                RFC 3921, October 2004.

Author's Address

  Peter Saint-Andre
  XMPP Standards Foundation
  P.O. Box 1641
  Denver, CO  80201
  USA

  EMail: [email protected]
  URI:   xmpp:[email protected]







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Full Copyright Statement

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Acknowledgement

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