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Network Working Group                                        M. LonnforsRequest for Comments: 5262                                         NokiaCategory: Standards Track                                    E. Leppanen                                                              Individual                                                            H. Khartabil                                                      Ericsson Australia                                                           J. Urpalainen                                                                   Nokia                                                          September 2008Presence Information Data Format (PIDF) Extension for Partial PresenceStatus 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.Abstract   The Presence Information Document Format (PIDF) specifies the   baseline XML-based format for describing presence information.  One   of the characteristics of the PIDF is that the 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 transported   information over the network.  This document introduces a new MIME   type that enables transporting of either only the changed parts or   the full PIDF-based presence information.Lonnfors, et al.            Standards Track                     [Page 1]

RFC 5262                      Partial PIDF                September 2008Table of Contents1. Introduction ....................................................22. Conventions .....................................................33. Structure of PIDF Diff Documents ................................33.1. 'version' Attribute ........................................43.2. 'entity' Attribute .........................................44. Usage of 'application/pidf-diff+xml' ............................45. IANA Considerations .............................................5      5.1. URN Sub-Namespace Registration for           'urn:ietf:params:xml:ns:pidf-diff' .........................55.2. application/pidf-diff+xml MIME Type ........................65.3. XML Schema Registration ....................................76. Examples ........................................................87. XML Schema .....................................................118. Interoperability Considerations ................................129. Security Considerations ........................................1310. Internationalization Considerations ...........................1311. Error Handling ................................................1312. Acknowledgments ...............................................1313. References ....................................................1313.1. Normative references .....................................1313.2. Informative references ...................................141.  Introduction   The Presence Information Document Format (PIDF) [RFC3863] specifies   the baseline XML-based format for describing presence information.   One of the characteristics of the PIDF is that the 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 transported   information over the network.   This document introduces a new MIME-Type 'application/pidf-diff+xml',   which enables transporting of either only the changed parts or the   full PIDF based presence information.  The root element of the   document distinguishes whether the partial or full PIDF document   content was transported.      Note: With this new MIME-Type, applications can easily negotiate      the support of partial updates of presence by using the Accept      header.  If PIDF had initially been designed for partial updates,      a new separate MIME-Type would have been unnecessary.Lonnfors, et al.            Standards Track                     [Page 2]

RFC 5262                      Partial PIDF                September 20082.  Conventions   The 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 inRFC 2119 [RFC2119] and   indicate requirement levels for compliant implementations.   This memo makes use of the vocabulary defined inRFC 2778 [RFC2778].   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      document can only be understood in the context of the full      presence document, i.e., a partial presence document modifies a      cached copy of the full presence document.3.  Structure of PIDF Diff Documents   The MIME type 'application/pidf-diff+xml' defines the new content   type for partial PIDF documents.   The XML Schema imports the PIDF [RFC3863] schema so that the full   PIDF document content with the addition of a 'version' attribute can   be transported.  The root element of the document is then   <pidf-full>, and the 'version' attribute information can be included   within it.  Otherwise, the content of <pidf-full> element is exactly   the same as what would have been if 'application/pidf+xml' content   type had been used.  Although the XML Schema also allows using   <presence> as the document root element, it is disallowed from   applications utilizing this document format.   When only the changes of the presence document are transported, the   model described in XML patch operations [RFC5261] is used.  The root   element of the document is then <pidf-diff>.  The patch operation   elements: <add>, <remove>, and <replace> allow changing the partial   content of the cached local copy of the full presence document.  The   <add> element is used to add new content, the <replace> element   updates, and the <remove> element removes existing content.   The optional 'version' attribute within the two possible document   root elements contains a sequence number which is incremented by one   between subsequent document updates, i.e., a more recent document   update has a higher 'version' value than the previous one.  This   number can be used to ensure consistent updates as the recipient ofLonnfors, et al.            Standards Track                     [Page 3]

RFC 5262                      Partial PIDF                September 2008   the document can use the 'version' number to properly order received   documents and to ensure that updates have not been lost.  The usage   of this attribute thus allows "state delta" processing described in   [RFC3265].  Partial notification [RFC5263] uses a similar model.   This number increments independently regardless of whether the   <pidf-full> or the <pidf-diff> content is transported.  In other   words, a single version counter is maintained across <pidf-full> and   <pidf-diff> documents.   Implementations using this document format MUST follow guidelines   specified in the PIDF [RFC3863] and PIDF extension formats, for   example, DataModel [RFC4479], Rich Presence Information Data (RPID)   [RFC4480], and Contact Information in PIDF (CIPID) [RFC4482] MUST   support the usage of the XML schema data type ID   [W3C.REC-xmlschema-2-20041028] of these listed RFCs.  Specifically,   the XML document MUST be well formed and SHOULD be valid.  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 [RFC2141], using the namespace   identifier 'ietf' specified inRFC 2648 [RFC2648] and extended byRFC3688 [RFC3688].  This URN is:   urn:ietf:params:xml:ns:pidf-diff3.1.  'version' Attribute   Every presence document compliant with this specification MAY contain   a 'version' attribute within the <pidf-diff> and <pidf-full> element.3.2.  'entity' Attribute   Every presence document compliant with this specification MAY contain   an 'entity' attribute within the <pidf-diff> element.  Its content, a   presentity URI, MUST then be the same as the 'entity' attribute value   of the <presence> element described in [RFC3863].  The usage of this   presentity URI is described in more detail inSection 3.1 of   [RFC4479].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   changes, the full presence document content can then be transported   instead.Lonnfors, et al.            Standards Track                     [Page 4]

RFC 5262                      Partial PIDF                September 20085.  IANA Considerations   IANA has performed the following actions:   o  registered a new XML namespace URN per [RFC3688].   o  registered a new MIME type 'application/pidf-diff+xml' according      to the procedures ofRFC 4288 [RFC4288] and guidelines inRFC 3023      [RFC3023].   o  registered a new XML Schema according to the procedures ofRFC3688 [RFC3688].5.1.  URN Sub-Namespace Registration for      'urn:ietf:params:xml:ns:pidf-diff'   This specification registers a new XML namespace, as per the   guidelines inRFC 3688 [RFC3688].      URI:      urn:ietf:params:xml:ns:pidf-diff      Description:      This is the XML namespace for XML elements defined byRFC 5262 to      describe the 'application/pidf-diff+xml' content type for partial      PIDF.      Registrant Contact:      IETF, SIMPLE working group, (simple@ietf.org)      Jari Urpalainen, (jari.urpalainen@nokia.com)Lonnfors, et al.            Standards Track                     [Page 5]

RFC 5262                      Partial PIDF                September 2008   XML:   BEGIN   <?xml version="1.0"?>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"     "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">   <html xmlns="http://www.w3.org/1999/xhtml">     <head>       <meta http-equiv="content-type"             content="text/html;charset=iso-8859-1"/>       <title>PIDF extension for partial PIDF</title>     </head>     <body>       <h1>Namespace for PIDF extension for partial           notifications</h1>       <h2>urn:ietf:params:xml:ns:pidf-diff</h2>       <p>See <a href="http://www.rfc-editor.org/rfc/rfc5262.txt">RFC5262</a>.</p>     </body>   </html>   END5.2.  application/pidf-diff+xml MIME Type   MIME media type name: application   MIME subtype name: pidf-diff+xml   Mandatory parameters: none   Optional parameters:   Same as charset parameter of application/xml as specified inRFC 3023   [RFC3023].  Default value is UTF-8.   Encoding considerations:   Same as encoding considerations of application/xml as specified inRFC 3023 [RFC3023].   Security considerations:   SeeSection 10 of RFC 3023 [RFC3023].  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.   Interoperability considerations: none   Published specification:RFC 5262Lonnfors, et al.            Standards Track                     [Page 6]

RFC 5262                      Partial PIDF                September 2008   Applications that use this media type: SIP-based presence systems   Additional information:      Magic Number: None      File Extension: .xml      Macintosh file type code: "TEXT"   Personal and email address for further information: Jari Urpalainen,   jari.urpalainen@nokia.com   Intended usage: LIMITED USE   Restrictions on usage: Presence [RFC3863] based systems.   Author:   This specification is a work item of the IETF SIMPLE working group,   with mailing list address <simple@ietf.org>.   Author/Change controller: the IETF.5.3.  XML Schema Registration   This section calls for IANA to register a new XML Schema, the sole   content of which can be found inSection 7.      URI:      urn:ietf:params:xml:schema:pidf-diff      Registrant Contact:      IETF, SIMPLE working group, <simple@ietf.org>      Jari Urpalainen, <jari.urpalainen@nokia.com>Lonnfors, et al.            Standards Track                     [Page 7]

RFC 5262                      Partial PIDF                September 20086.  Examples   An 'application/pidf-diff+xml' document that contains the full state   presence information:   <?xml version="1.0" encoding="UTF-8"?>   <p:pidf-full xmlns="urn:ietf:params:xml:ns:pidf"          xmlns:p="urn:ietf:params:xml:ns:pidf-diff"          xmlns:r="urn:ietf:params:xml:ns:pidf:rpid"          xmlns:ci="urn:ietf:params:xml:ns:pidf:cipid"          xmlns:c="urn:ietf:params:xml:ns:pidf:caps"          xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"          entity="pres:someone@example.com"          version="567">    <tuple>     <status>      <basic>open</basic>     </status>     <c:servcaps>      <c:audio>true</c:audio>      <c:message>true</c:message>      <c:video>false</c:video>     </c:servcaps>     <contact priority="0.8">tel:09012345678</contact>    </tuple>    <tuple>     <status>      <basic>open</basic>     </status>     <contact priority="1.0">im:pep@example.com</contact>    </tuple>    <tuple>     <status>      <basic>closed</basic>     </status>     <ci:homepage>http://example.com/~pep/</ci:homepage>     <ci:icon>http://example.com/~pep/icon.gif</ci:icon>     <ci:card>http://example.com/~pep/card.vcd</ci:card>     <contact priority="0.9">sip:pep@example.com</contact>    </tuple>    <note xml:lang="en">Full state presence document</note>    <dm:person>     <r:activities>Lonnfors, et al.            Standards Track                     [Page 8]

RFC 5262                      Partial PIDF                September 2008      <r:on-the-phone/>      <r:busy/>     </r:activities>    </dm:person>    <dm:device>     <c:devcaps>      <c:mobility>       <c:supported>        <c:mobile/>       </c:supported>      </c:mobility>     </c:devcaps>     <dm:deviceID>urn:esn:600b40c7</dm:deviceID>    </dm:device>   </p:pidf-full>   An example partial update document with the <pidf-diff> root element:   <?xml version="1.0" encoding="UTF-8"?>   <p:pidf-diff        xmlns="urn:ietf:params:xml:ns:pidf"        xmlns:p="urn:ietf:params:xml:ns:pidf-diff"        xmlns:r="urn:ietf:params:xml:ns:pidf:rpid"        xmlns:d="urn:ietf:params:xml:ns:pidf:data-model"        entity="pres:someone@example.com"        version="568">   <p:add sel="presence/note" pos="before">    <tuple>     <status>      <basic>open</basic>     </status>     <contact priority="0.4">mailto:pep@example.com</contact>     <note xml:lang="en">This is a new tuple inserted          between the last tuple and person element</note>    </tuple>   </p:add>   <p:replace sel="*/tuple[@id='r1230d']/status/basic/text()"      >open</p:replace>   <p:remove sel="*/d:person/r:activities/r:busy" ws="after"/>   <p:replace sel="*/tuple[@id='cg231jcr']/contact/@priority"      >0.7</p:replace>   </p:pidf-diff>Lonnfors, et al.            Standards Track                     [Page 9]

RFC 5262                      Partial PIDF                September 2008   An updated local composition presence document after applying the   patches:   <?xml version="1.0" encoding="UTF-8"?>   <p:pidf-full xmlns="urn:ietf:params:xml:ns:pidf"          xmlns:p="urn:ietf:params:xml:ns:pidf-diff"          xmlns:r="urn:ietf:params:xml:ns:pidf:rpid"          xmlns:ci="urn:ietf:params:xml:ns:pidf:cipid"          xmlns:c="urn:ietf:params:xml:ns:pidf:caps"          xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"          entity="pres:someone@example.com"          version="568">    <tuple>     <status>      <basic>open</basic>     </status>     <c:servcaps>      <c:audio>true</c:audio>      <c:message>true</c:message>      <c:video>false</c:video>     </c:servcaps>     <contact priority="0.8">tel:09012345678</contact>    </tuple>    <tuple>     <status>      <basic>open</basic>     </status>     <contact priority="0.7">im:pep@example.com</contact>    </tuple>    <tuple>     <status>      <basic>open</basic>     </status>     <ci:homepage>http://example.com/~pep/</ci:homepage>     <ci:icon>http://example.com/~pep/icon.gif</ci:icon>     <ci:card>http://example.com/~pep/card.vcd</ci:card>     <contact priority="0.9">sip:pep@example.com</contact>    </tuple>    <tuple>     <status>      <basic>open</basic>     </status>     <contact priority="0.4">mailto:pep@example.com</contact>Lonnfors, et al.            Standards Track                    [Page 10]

RFC 5262                      Partial PIDF                September 2008     <note xml:lang="en">This is a new tuple inserted         between the last tuple and note element</note>    </tuple>    <note xml:lang="en">Full state presence document</note>    <dm:person>     <r:activities>      <r:on-the-phone/>     </r:activities>    </dm:person>    <dm:device>     <c:devcaps>      <c:mobility>       <c:supported>        <c:mobile/>       </c:supported>      </c:mobility>     </c:devcaps>     <dm:deviceID>urn:esn:600b40c7</dm:deviceID>    </dm:device>   </p:pidf-full>7.  XML Schema   The XML schema for the 'application/pidf-diff+xml' data format.  The   included schema "urn:ietf:params:xml:schema:xml-patch-ops" is defined   in [RFC5261], and the PIDF Schema "pidf.xsd" is imported from   [RFC3863].   <?xml version="1.0" encoding="UTF-8"?>   <xsd:schema       targetNamespace="urn:ietf:params:xml:ns:pidf-diff"       xmlns:tns="urn:ietf:params:xml:ns:pidf-diff"       xmlns:pidf="urn:ietf:params:xml:ns:pidf"       xmlns:xsd="http://www.w3.org/2001/XMLSchema"       elementFormDefault="qualified">    <!-- include patch-ops type definitions -->    <xsd:include         schemaLocation="urn:ietf:params:xml:schema:patch-ops"/>    <!-- import PIDF definitions -->    <xsd:import namespace="urn:ietf:params:xml:ns:pidf"                schemaLocation="pidf.xsd"/>Lonnfors, et al.            Standards Track                    [Page 11]

RFC 5262                      Partial PIDF                September 2008    <!-- partial updates -->    <xsd:element name="pidf-diff">     <xsd:complexType>      <xsd:sequence minOccurs="0" maxOccurs="unbounded">       <xsd:choice>        <xsd:element name="add" type="tns:add"/>        <xsd:element name="replace" type="tns:replace"/>        <xsd:element name="remove" type="tns:remove"/>       </xsd:choice>      </xsd:sequence>      <xsd:attribute name="version" type="xsd:unsignedInt"/>      <xsd:attribute name="entity" type="xsd:anyURI"/>     </xsd:complexType>    </xsd:element>    <!-- full PIDF in addition to optional version -->    <xsd:element name="pidf-full">     <xsd:complexType>      <xsd:complexContent>       <xsd:extension base="pidf:presence">        <xsd:attribute name="version" type="xsd:unsignedInt"/>       </xsd:extension>      </xsd:complexContent>     </xsd:complexType>    </xsd:element>   </xsd:schema>8.  Interoperability Considerations   Systems compliant with Common Profile for Presence (CPP) [RFC3859]   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 of if they support this   specification.  Thus, if a gateway or another end point does not   understand this specification it will not be used.  In SIMPLE-based   systems, use of this MIME type is negotiated using SIP content type   negotiation mechanism as specified in partial notification [RFC5263].   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 that will preserve   end-to-end integrity with usage of partial PIDF.Lonnfors, et al.            Standards Track                    [Page 12]

RFC 5262                      Partial PIDF                September 20089.  Security Considerations   All security considerations identified for PIDF [RFC3863] apply   unchanged for this document as presence information may contain   highly sensitive information.  Furthermore, the protocol SHOULD   provide authorization policies what presence information can be given   to which watchers, and when, see [RFC5025].10.  Internationalization Considerations   The PIDF [RFC3863] format is represented in XML that performs all   character processing in terms of the Universal Character Set (UCS).   Conformant XML processors MUST support both UTF-8 and UTF-16   encodings of the UCS.  UTF-8 is the RECOMMENDED encoding of this   partial presence format.   If the character set of the initial <pidf-full> document has been   accepted by a receiving application, it MUST continue to accept the   same character set with the subsequent <pidf-diff> documents.   However, it MUST NOT need to accept a possible character set change.11.  Error Handling   Error conditions MAY be indicated by errors defined in [RFC5261].   This document doesn't define any additional error elements.  If the   'version' or 'entity' attributes have incorrect content, it MAY be   indicated by the <invalid-attribute-value> error element.12.  Acknowledgments   The authors would like to thank Jose Costa-Requena, Jyrki Aarnos,   Jonathan Rosenberg, Dean Willis, Miguel Garcia, Krisztian Kiss, Ben   Cambell, Robert Sparks, Anders Kristenssen, Aki Niemi, Jon Peterson,   Gonzalo Camarillo, Lars Eggert, Lakshminath Dondeti, and Chris Newman   for their valuable comments and contributions.13.  References13.1.  Normative references   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [RFC3863]  Sugano, H., Fujimoto, S., Klyne, G., Bateman, A., Carr,              W., and J. Peterson, "Presence Information Data Format              (PIDF)",RFC 3863, August 2004.Lonnfors, et al.            Standards Track                    [Page 13]

RFC 5262                      Partial PIDF                September 2008   [RFC2141]  Moats, R., "URN Syntax",RFC 2141, May 1997.   [RFC2648]  Moats, R., "A URN Namespace for IETF Documents",RFC 2648,              August 1999.   [RFC3688]  Mealling, M., "The IETF XML Registry",BCP 81,RFC 3688,              January 2004.   [RFC3023]  Murata, M., St. Laurent, S., and D. Kohn, "XML Media              Types",RFC 3023, January 2001.   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and              Registration Procedures",BCP 13,RFC 4288, December 2005.   [RFC4479]  Rosenberg, J., "A Data Model for Presence",RFC 4479, July              2006.   [RFC4480]  Schulzrinne, H., Gurbani, V., Kyzivat, P., and J.              Rosenberg, "RPID: Rich Presence Extensions to the Presence              Information Data Format (PIDF)",RFC 4480, July 2006.   [RFC4482]  Schulzrinne, H., "CIPID: Contact Information for the              Presence Information Data Format",RFC 4482, July 2006.   [RFC5261]  Urpalainen, J., "An Extensible Markup Language (XML) Patch              Operations Framework Utilizing XML Path Language (XPath)              Selectors",RFC 5261, September 2008.   [W3C.REC-xmlschema-2-20041028]              Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes              Second Edition", World Wide Web Consortium Recommendation              REC-xmlschema-2-20041028, October 2004,              <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.13.2.  Informative references   [RFC2778]  Day, M., Rosenberg, J., and H. Sugano, "A Model for              Presence and Instant Messaging",RFC 2778, February 2000.   [RFC3265]  Roach, A., "Session Initiation Protocol (SIP)-Specific              Event Notification",RFC 3265, June 2002.   [RFC3859]  Peterson, J., "Common Profile for Presence (CPP)",RFC3859, August 2004.   [RFC5025]  Rosenberg, J., "Presence Authorization Rules",RFC 5025,              December 2007.Lonnfors, et al.            Standards Track                    [Page 14]

RFC 5262                      Partial PIDF                September 2008   [RFC5263]  Lonnfors, M., "Session Initiation Protocol (SIP) Extension              for Partial Notification of Presence Information",RFC5263, September 2008.Authors' Addresses   Mikko Lonnfors   Nokia   Itamerenkatu 11-13 00180   Helsinki   Finland   Phone: +358 71 8008000   EMail: mikko.lonnfors@nokia.com   Eva Leppanen   Individual   Lempaala   Finland   EMail: eva.leppanen@saunalahti.fi   Hisham Khartabil   Ericsson Australia   P.O. Box 256c   Melbourne, VIC 3001   Australia   EMail: hisham.khartabil@gmail.com   Jari Urpalainen   Nokia   Itamerenkatu 11-13 00180   Helsinki   Finland   Phone: +358 7180 37686   EMail: jari.urpalainen@nokia.comLonnfors, et al.            Standards Track                    [Page 15]

RFC 5262                      Partial PIDF                September 2008Full Copyright Statement   Copyright (C) The IETF Trust (2008).   This document is subject to the rights, licenses and restrictions   contained inBCP 78, and except as set forth therein, the authors   retain all their rights.   This document and the information contained herein are provided on an   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND   THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the procedures with respect to rights in RFC documents can be   found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at   ietf-ipr@ietf.org.Lonnfors, et al.            Standards Track                    [Page 16]