SIMPLE WG M. Lonnfors Internet-Draft E. Leppanen Expires: August 25, 2005 Nokia H. Khartabil Telio J. Urpalainen Nokia Research Center February 21, 2005 Presence Information Data format (PIDF) Extension for Partial Presence draft-ietf-simple-partial-pidf-format-03 Status of this Memo This document is an Internet-Draft and is subject to all provisions of Section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 25, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract The Presence Information Document Format (PIDF) specifies the Lonnfors, et al. Expires August 25, 2005 [Page 1] Internet-Draft Partial PIDF February 2005 baseline XML based format for describing presence information. One of the characteristic of the PIDF is that document always needs to carry all presence information available for the presentity. In some environments where low bandwidth and high latency links can exist it is often beneficial to limit the amount of information that is transported over the network. This document introduces a new MIME type which enables transporting of only changed parts of the PIDF based presence information. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Structure of partial PIDF documents . . . . . . . . . . . . 3 3.1 'version' attribute . . . . . . . . . . . . . . . . . . . 4 3.2 'entity' attribute . . . . . . . . . . . . . . . . . . . . 4 4. Usage of 'application/pidf-diff+xml' . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . 5 5.1 Content-type registration for 'application/pidf-diff+xml' . . . . . . . . . . . . . . . 5 5.2 URN sub-namespace registration for 'urn:ietf:params:xml:ns:pidf-diff' . . . . . . . . . . . . 6 5.3 XML Schema Registration . . . . . . . . . . . . . . . . . 7 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. Interoperability Considerations . . . . . . . . . . . . . . 12 9. Security Considerations . . . . . . . . . . . . . . . . . . 12 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 12 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 11.1 Normative references . . . . . . . . . . . . . . . . . . 12 11.2 Informative references . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . 15 Lonnfors, et al. Expires August 25, 2005 [Page 2] Internet-Draft Partial PIDF February 2005 1. Introduction The Presence Information Document Format (PIDF) specifies the baseline XML based format for describing presence information. One of the characteristic of the PIDF is that document always needs to carry all presence information available for the presentity. In some environments where low bandwidth and high latency links can exist it is often beneficial to limit the amount of information that is transported over the network. This document introduces a new MIME-Type 'application/pidf-diff+xml' which enables transporting of only changed parts of the PIDF based presence information. 2. Conventions In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and indicate requirement levels for compliant implementations. This memo makes use of the vocabulary defined in RFC2778 [2]. In addition, the following terms are defined: Full presence document: A presence document that contains all the presentity's presence information that is available to a particular watcher. Partial presence document: A presence document that represents a fragment of the full presence document. A partial presence documents can only be understood in the context of the full presence document, i.e., a partial presence document modifies a local copy of the full presence document. A document with MIME type 'application/pidf-diff+xml' represents a partial presence document. 3. Structure of partial PIDF documents The mechanism for implementing the partial PIDF requires defining a new MIME type which is named as 'application/pidf-diff+xml'. The data format includes XML Schema types described in [7]. The patch operation elements: , or defined according to the patch operation XML Schema types will allow changing the fragments of the local copy of the full presence document. As the names imply the element is used to add new content and element is used to update the existing content whereas Lonnfors, et al. Expires August 25, 2005 [Page 3] Internet-Draft Partial PIDF February 2005 element is used to remove some content. In addition to patch operation elements the data format consists of some additional parameters. The 'version' attribute within the document root node contains a sequence number that is progressively incremented by one between subsequent document updates i.e. a more recent document update has a higher 'version' value than the previous one. This is used to ensure consistent updates as the recipient of the document can use the 'version' attribute value to properly order received documents. Implementations using this document format must follow guidelines specified in the PIDF [3]. Specifically, the XML document MUST be well formed and SHOULD be valid. Presence documents MUST be based on XML 1.0 and MUST be encoded using UTF-8. This specification makes use of XML namespaces for identifying presence documents and document fragments. The namespace URI for elements defined by this specification is a URN [4], using the namespace identifier 'ietf' specified in RFC 2648 [5] and extended by RFC3688 [6]. This URN is: urn:ietf:params:xml:ns:pidf-diff 3.1 'version' attribute Every presence document compliant with this specification contains a 'version' attribute in the element. 3.2 'entity' attribute Every presence document compliant with this specification MAY contain an 'entity' attribute in the root document node. It's content MUST then be the same than that of the full presence document. 4. Usage of 'application/pidf-diff+xml' The partial presence document SHOULD only contain those elements or attributes that have changed. However, when there are a lot of queued changes it may be desirable to send the full presence document content instead. How this will be done in practice is beyond the scope of this document. This document format allows to use the root node selector i.e. "presence" which actually contains the full content of the presence document as there can only be one root node in any valid XML document. It should be noted that it is still impossible to create a new document with this format, i.e. first the full presence document has to be sent with the PIDF format and then only patches are sent with this pidf-diff format. Lonnfors, et al. Expires August 25, 2005 [Page 4] Internet-Draft Partial PIDF February 2005 5. IANA Considerations This memo calls for IANA to: o register a new XML namespace URN per [6]. o register a new content type 'application/pidf-diff+xml' per RFC2048 [10]. o register a new XML Schema URN per [6]. 5.1 Content-type registration for 'application/pidf-diff+xml' MIME media type name: application MIME subtype name: pidf-diff+xml Mandatory parameters: none Optional parameters: charset Indicates the character encoding of enclosed XML. Default is UTF-8. Encoding considerations: Uses XML, which can employ 8-bit characters, depending on the character encoding used. See RFC 3023 [8], section 3.2. Security considerations: This content type is designed to carry presence data, which may be considered private information. Appropriate precautions should be adopted to limit disclosure of this information. Please refer to [[[RFCXXXX]]] security considerations section for more information. Interoperability considerations: none Published specification: [[[RFCXXXX]]] Applications which use this media type: SIP-based presence systems Additional information: Magic Number: None File Extension: .xml Macintosh file type code: "TEXT" Lonnfors, et al. Expires August 25, 2005 [Page 5] Internet-Draft Partial PIDF February 2005 Personal and email address for further information: Mikko Lonnfors, mikko.lonnfors@nokia.com Intended usage: LIMITED USE Author/Change controller: This specification is a work item of the IETF SIMPLE working group, with mailing list address . 5.2 URN sub-namespace registration for 'urn:ietf:params:xml:ns:pidf-diff' URI: urn:ietf:params:xml:ns:pidf-diff Description: This is the XML namespace for XML elements defined by [[[RFCXXXX]]] to describe the 'application/pidf-diff+xml' content type for partial PIDF. Registrant Contact: IETF, SIMPLE working group, Mikko Lonnfors, XML: BEGIN PIDF extension for partial PIDF

Namespace for PIDF extension for partial notifications

urn:ietf:params:xml:ns:pidf-diff

See RFCXXXX.

END Lonnfors, et al. Expires August 25, 2005 [Page 6] Internet-Draft Partial PIDF February 2005 5.3 XML Schema Registration This section registers a new XML Schema. URI: urn:ietf:params:xml:schema:pidf-diff Registrant Contact: IETF, SIMPLE working group, Mikko Lonnfors, 6. Examples An 'application/pidf+xml' document that contains full state information: open assistant true false true tel:09012345678 open im:pep@example.com Lonnfors, et al. Expires August 25, 2005 [Page 7] Internet-Draft Partial PIDF February 2005 closed meeting http://example.com/~pep/ http://example.com/~pep/icon.gif http://example.com/~pep/card.vcd sip:pep@example.com Full state presence document An 'application/pidf-diff+xml' document that contains four example updates: Lonnfors, et al. Expires August 25, 2005 [Page 8] Internet-Draft Partial PIDF February 2005 open mailto:pep@example.com This is a new tuple inserted between the last tuple and person element open 0.7 An updated local composition presence document after applying the patches: open assistant Lonnfors, et al. Expires August 25, 2005 [Page 9] Internet-Draft Partial PIDF February 2005 true false true tel:09012345678 open im:pep@example.com open http://example.com/~pep/ http://example.com/~pep/icon.gif http://example.com/~pep/card.vcd sip:pep@example.com open mailto:pep@example.com This is a new tuple inserted between the last tuple and person element Lonnfors, et al. Expires August 25, 2005 [Page 10] Internet-Draft Partial PIDF February 2005 Full state presence document 7. XML Schema The XML schema for the 'application/pidf-diff+xml' data format. The included schema "xcap-patch-opers.xsd" is defined in [7]. Lonnfors, et al. Expires August 25, 2005 [Page 11] Internet-Draft Partial PIDF February 2005 8. Interoperability Considerations Systems compliant with CPP [9] will not be by default able to use this specification. However, this will not cause any interoperability problems because all endpoints and gateways must support the default MIME type (application/pidf+xml) regardless if they support this specification. Thus if a gateway or another end point does not understand this specification it will not be used. Other CPP compliant (other than SIP based) systems can also support this specification if they have a mechanism to indicate support for it. If they do it is possible to build a gateway which will preserve end-to-end integrity with usage of partial PIDF. 9. Security Considerations Presence information may contain highly sensitive information about the presentities. The protocol used to distribute it SHOULD ensure privacy, message integrity and authentication. Furthermore, the protocol should provide access controls which restrict who can see who else's presence information. All security considerations identified for PIDF [3] apply unchanged for this document. 10. Acknowledgments The authors would like to thank Jose Costa-Requena, Jyrki Aarnos, Jonathan Rosenberg, Dean Willis, Miguel Garcia, Kriztian Kiss, Ben Cambell, Robert Sparks, Anders kristenssen and Aki Niemi for their valuable comments and contributions. 11. References 11.1 Normative references [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Day, M., Rosenberg, J. and H. Sugano, "A Model for Presence and Instant Messaging", RFC 2778, February 2000. [3] Sugano, H., "CPIM presence information data format", RFC 3863, May 2003. [4] Moats, R., "URN syntax", RFC 2141, May 1997. [5] Moats, R., "A URN namespace for IETF documents", RFC 2648, Aug. 1999. Lonnfors, et al. Expires August 25, 2005 [Page 12] Internet-Draft Partial PIDF February 2005 [6] Mealling, M., "The IETF XML Registry", RFC 3688, BCP 81, January 2004. [7] Urpalainen, J., "The Extensible Markup Language (XML) Configuration Access Protocol (XCAP) Patch Operations", draft-urpalainen-simple-xcap-patch-ops-00, February 2005. 11.2 Informative references [8] Murata, M., "XML media types", RFC 3023, January 2001. [9] Peterson, J., "Common Profile for Presence (CPP)", RFC 3859. [10] Freed, N., Klensin, J. and J. Postel, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, November 1996. [11] Rosenberg, J., "A Data Model for Presence", draft-ietf-simple-presence-data-model-01 (work in progress), October 2004. [12] Schulzrinne, H., Gurbani, V., Kyzivat, P. and J. Rosenberg, "RPID: Rich Presence Extensions to the Presence Information Data Format (PIDF)", draft-ietf-simple-rpid-04 (work in progress), October 2004. [13] Schulzrinne, H., "CIPID: Contact Information in Presence Information Data Format", draft-ietf-simple-cipid-03 (work in progress), July 2004. Authors' Addresses Mikko Lonnfors Nokia Itamerenkatu 11-13 00180 Helsinki Finland Phone: +358 71 8008000 Email: mikko.lonnfors@nokia.com Lonnfors, et al. Expires August 25, 2005 [Page 13] Internet-Draft Partial PIDF February 2005 Eva Leppanen Nokia P.O BOX 785 Tampere Finland Phone: +358 7180 77066 Email: eva-maria.leppanen@nokia.com Hisham Khartabil Telio P.O. Box 1203 Vika Oslo Norway Phone: +47 2167 3544 Email: hisham.khartabil@telio.no Jari Urpalainen Nokia Research Center Itamerenkatu 11-13 00180 Helsinki Finland Phone: +358 7180 37686 Email: jari.urpalainen@nokia.com Lonnfors, et al. 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Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Lonnfors, et al. Expires August 25, 2005 [Page 15]