Network Working Group P. Saint-Andre
Internet-Draft Jabber Software Foundation
Expires: August 6, 2004 February 6, 2004
Transporting Presence Information Data Format (PIDF) over the
Extensible Messaging and Presence Protocol (XMPP)
draft-saintandre-xmpp-pidf-00
Status of this Memo
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Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document defines how to send information encoded in the CPIM
Presence Information Data Format (PIDF) over the Extensible Messaging
and Presence Protocol (XMPP).
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Discussion Venue . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
Normative References . . . . . . . . . . . . . . . . . . . . . 5
Informative References . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . 7
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1. Introduction
The Presence Information Data Format ([PIDF]) defines a common
presence data format for presence protocols that conform to the
Common Profile for Presence ([CPP]), enabling presence information to
be transferred across CPP-compliant protocol boundaries without
modification, with attendant benefits for security and performance.
Because the syntax for PIDF is XML [XML], it should be
straightforward to send PIDF data over the Extensible Messaging and
Presence Protocol [XMPP-CORE], since XMPP is simply an XML streaming
protocol. This memo defines a mechanism for encapsulating PIDF data
within an "extended namespace" contained in an XMPP presence stanza.
1.1 Terminology
This document inherits terminology defined in [PIDF], [XMPP-CORE],
and [XMPP-IM].
The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119 [TERMS].
1.2 Discussion Venue
The author welcomes discussion and comments related to the topics
presented in this document. The preferred forum is the
<xmppwg@jabber.org> mailing list, for which archives and subscription
information are available at <http://www.jabber.org/cgi-bin/mailman/
listinfo/xmppwg/>.
2. Protocol
The PIDF format is defined in [PIDF]. Briefly, the XML namespace
name is 'urn:ietf:params:xml:ns:pidf', the root element is <presence/
>, the <presence/> element must possess an 'entity' attribute, and
the <presence/> element may contain any number of <tuple/> child
elements specying information about an entity.
The recommended method for encapsulating PIDF data within an XMPP
presence stanza is by including the PIDF <presence/> element as a
child of the XMPP <presence/> stanza. Although it may appear that
this is potentially confusing, the inclusion of the
'urn:ietf:params:xml:ns:pidf' namespace ensures that PIDF data is
kept separate from XMPP presence data (in accordance with
[XML-NAMES]). The following is a simple example of encapsulating
PIDF data within an "extended namespace" in XMPP:
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A basic example of PIDF over XMPP:
<presence from='romeo@example.net/orchard' xml:lang='en'>
<show>dnd</show>
<status>Wooing Juliet</status>
<presence xmlns='urn:ietf:params:xml:ns:pidf'
entity='pres:romeo@example.net'>
<tuple id='orchard'>
<status>
<basic>open</basic>
</status>
</tuple>
</presence>
</presence>
Because base PIDF data does not encapsulate any additional
information over and above XMPP presence stanzas, there is little
point to including it in native XMPP systems when it is not encrypted
(obviously, encrypting PIDF data can help to ensure end-to-end
encryption of presence information, as described in [XMPP-E2E]). The
power of PIDF in the context of XMPP derives from extensions thereto,
such as the rich presence formats described in [RPID] and the
geographical location formats described in [GEOLOC]. Any such
extension to PIDF can be included in an XMPP presence stanza, since,
according to the definition of "extended namespaces" in [XMPP-IM],
the format of such extended data is defined by the extension rather
than by the base XMPP specification itself. Thus the ability to
include PIDF data and PIDF data extensions in XMPP enables XMPP-aware
applications to include any PIDF-compatible data that is currently
defined or that may be defined in the future. Naturally, there is no
guarantee that all XMPP entities will be able to understand such PIDF
data, and entities that do not understand the data MUST ignore it;
however, this memo at least defines a mechanism for including PIDF
data, which XMPP applications are encouraged to implement if they
desire to make use of PIDF data extensions for rich presence,
geographical location, and other kinds of presence-related
information.
3. IANA Considerations
This document requires no action on the part of the IANA.
4. Security Considerations
Detailed security considerations for XMPP are given in XMPP Core
[XMPP-CORE].
Normative References
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[CPP] Peterson, J., "Common Profile for Presence (CPP)",
draft-ietf-impp-pres-04 (work in progress), August 2003.
[PIDF] Fujimoto, S., Sugano, H., Klyne, G., Bateman, A., Carr, W.
and J. Peterson, "Presence Information Data Format
(PIDF)", draft-ietf-impp-cpim-pidf-08 (work in progress),
May 2003.
[TERMS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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", draft-ietf-xmpp-core-22 (work in
progress), January 2004.
[XMPP-E2E]
Saint-Andre, P., "End-to-End Object Encryption in the
Extensible Messaging and Presence Protocol (XMPP)",
draft-ietf-xmpp-e2e-07 (work in progress), December 2003.
[XMPP-IM] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Instant Messaging and Presence",
draft-ietf-xmpp-im-21 (work in progress), January 2004.
Informative References
[GEOLOC] Peterson, J., "A Presence-based GEOPRIV Location Object
Format", draft-ietf-geopriv-pidf-lo-00 (work in progress),
January 2004.
[RPID] Schulzrinne, H., "RPID -- Rich Presence Information Data
Format", draft-ietf-simple-rpid-00 (work in progress), July
2003.
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Author's Address
Peter Saint-Andre
Jabber Software Foundation
EMail: stpeter@jabber.org
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