SIMPLE WG M. Isomaki Internet-Draft Nokia Research Center Expires: April 2, 2004 E. Leppanen Nokia October 3, 2003 An Extensible Markup Language (XML) Configuraion Access Protocol (XCAP) Usage for Publishing Presence Information draft-isomaki-simple-xcap-publish-usage-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 April 2, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document describes a usage of the Extensible Markup Language (XML) Configuration Access Protocol (XCAP) for publishers for manipulating the hard state type of presence information within SIMPLE presence publication framework. Isomaki & Leppanen Expires April 2, 2004 [Page 1] Internet-Draft XCAP Usage for Presence Publishing October 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Application Unique ID . . . . . . . . . . . . . . . . . . . 5 5. Structure of Published Presence Information . . . . . . . . 5 6. Computed Data . . . . . . . . . . . . . . . . . . . . . . . 5 7. Additional Constraints . . . . . . . . . . . . . . . . . . . 5 8. Naming Conventions . . . . . . . . . . . . . . . . . . . . . 5 9. Authorization Policies . . . . . . . . . . . . . . . . . . . 5 10. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . 5 11. Example Document . . . . . . . . . . . . . . . . . . . . . . 6 12. Security Considerations . . . . . . . . . . . . . . . . . . 7 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . 7 13.1 XCAP Application Usage ID . . . . . . . . . . . . . . . . . 7 14. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 7 15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 Normative References . . . . . . . . . . . . . . . . . . . . 8 Informative References . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . 10 Isomaki & Leppanen Expires April 2, 2004 [Page 2] Internet-Draft XCAP Usage for Presence Publishing October 2003 1. Introduction The Session Initiation Protocol (SIP) for Instant Messaging and Presence (SIMPLE) specifications allow a user, called a watcher, to subscribe to another user, called a presentity [6], in order to learn their presence information [7]. The presence information is published by the user, called a publisher. The presence server (PS) and presence agent (PA) have access to the stored presence information. A SIP based mechanism has been specified for publishing soft state type of presence information [13]. However, there is also a need to manage such presence information which neither requires refreshing nor needs definition of the expiry time, e.g., the presence information of a closed communication mean or some other more stabile information. Examples include for instance presentity's e-mail or homepage address. This kind of information is normally managed only when there is a need to change the content. Such information is called hard state type of presence information in this document. XML Configuration Access Protocol (XCAP) [2] allows a client to read, write and modify application configuration data, stored in XML format on a server. The data has no expiration time, so it must be explicitly inserted and deleted. It is possible to manipulate the same data by multiple clients. With these properties XCAP fulfills the requirements of hard state information publishing. Another advantage is that XCAP is used in SIP-based presence systems also for manipulation of presence lists and presence authorization policies. This document defines an XML Configuration Access Protocol (XCAP) application usage for manipulating hard state type of presence information. CPIM PIDF [3] presence document format, which is used for soft state information, is reused for hard state presence in order to make the combination of different types of information easier. Section 3 introduces a framework how XCAP-based hard state presence information publishing is related to soft state publishing done with SIP. XCAP requires application usages to standardize several pieces of information, including an application unique ID (AUID), an XML schema, and various other information. These pieces of information are specified starting from the Section 4. 2. Conventions In this document, the key words 'MUST', 'MUST NOT', 'REQUIRED', Isomaki & Leppanen Expires April 2, 2004 [Page 3] Internet-Draft XCAP Usage for Presence Publishing October 2003 '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. Comprehensive terminology of presence and event state publishing is provided in [13]. 3. Framework The framework for publishing presence state is introduced in [12]. A central part of the framework is the event state compositor element which function is to compose presence information received from serveral sources. The hard state information can be seen as one of the information sources for the compositor to be combined with the soft state information published using SIP PUBLISH [13]. This is illustrated in the figure below. In order to make the combination easier, hard state information uses the same format as soft state information, namely CPIM PIDF and any of its extensions. +---------------+ +------------+ | Event State | | Presence |--> SIP Subscribe | Compositor +---------+ Agent |<-- SIP Notify | | | (PA) | +-------+-------+ +------------+ | | | +---------------+ +--------------^-------------| XCAP server | | | +-------+-------+ | | ^ | SIP Publish | | XCAP Publish | | | +--+--+ +--+--+ +--------+--------------+ | PUA | | PUA | | XCAP presence-publish | | | | | | client | +-----+ +-----+ +-----------------------+ Figure 1: Framework for Publishing How the compositor combines the hard state information with the soft state information to form a coherent presence document is entirely a matter of local policy, and is beyond the scope of this document. Isomaki & Leppanen Expires April 2, 2004 [Page 4] Internet-Draft XCAP Usage for Presence Publishing October 2003 4. Application Unique ID XCAP requires application usages to define a unique application usage ID (AUID) in either the IETF tree or a vendor tree. This specification defines the 'presence-publish' AUID within the IETF tree, via the IANA registration in the Section 13. 5. Structure of Published Presence Information The XML [5] format of the presence information (PIDF) is defined in [3] and its extensions. The PIDF defines the presence information to consist of the root element 'presence' including 'tuples' which contain a mandatory status element, a communication mean specific presence attribute and other markups. Additionally, the presence information can contain other presentity level information outside tuples. The namespace URI for PIDF is defined in [3]. 6. Computed Data There are no computed data on the document beyond those described in the schema. 7. Additional Constraints There are no constraints on the document beyond those described in the XML schemas and [3]. 8. Naming Conventions There are no naming conventions beyond the possible conventions defined in [3] that need to be defined for this application usage. 9. Authorization Policies This application usage does not modify the default XCAP authorization policy, which allows only a user (a publisher) to read, write or modify their own documents. A server can allow privileged users to modify documents that they don't own, but the establishment and indication of such policies is outside the scope of this document. 10. XML Schema The XML schema definition for the presence information can be found from [3] and its extensions. At the time of writing this draft the following extensions have been specified: [10] and [11]. Isomaki & Leppanen Expires April 2, 2004 [Page 5] Internet-Draft XCAP Usage for Presence Publishing October 2003 11. Example Document The following example document defines the default state of the presentity's presence information. In the absence of any published soft state information, this would be the sole input to the compositor forming the presence document. The example document contain PIDF extensions specified in [10] and [11]. I'm available only by e-mail. http://www.example.com/~someone assistant presentity open sip:secretary@example.com assistant Please contact my secretary. presentity Vacation home quiet 2001-10-27T16:49:29Z phone device closed 2001-10-27T16:49:29Z Isomaki & Leppanen Expires April 2, 2004 [Page 6] Internet-Draft XCAP Usage for Presence Publishing October 2003 mail device open mailto:someone@example.com 12. Security Considerations The configuration information defined by this application usage is particularly sensitive. It represents the set of presence information which is delivered to watchers according to specific authorization policies. As a result, clients SHOULD use TLS when contacting servers in order to fetch this information. Also if the server delivers presence information using the XCAP protocol it must be done according to the defined authorization policy. 13. IANA Considerations There are an IANA consideration associated with this specification. 13.1 XCAP Application Usage ID This section registers a new XCAP Application Usage ID (AUID) according to the IANA procedures defined in [2]. Name of the AUID: presence-publish Description: A presence-publish application is a usage of the publish framework for managing hard state type of presence information using XCAP. 14. Open Issues Publishing of external content: how to publish external content (e.g., an icon) referenced from PIDF in case of the XCAP based publishing? Is the content transported separately from the PIDF formatted document so that the PIDF includes only a reference to the separately transported content and the compositor is capable for linking the information together? This might require that the Isomaki & Leppanen Expires April 2, 2004 [Page 7] Internet-Draft XCAP Usage for Presence Publishing October 2003 compositor is able to change the content of the reference. 15. Acknowledgements The authors would like to thank J. Rosenberg for providing the 'template' for this draft, Aki Niemi for giving good assistance, and Krisztian Kiss and Jose Costa-Requena for reviewing the draft. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Rosenberg, J., "The Extensible Markup Language (XML) Configuration Access Protocol (XCAP)", draft-rosenberg-simple-xcap-00 (work in progress), May 2003. [3] Sugano, H., "CPIM presence information data format", draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003. Informative References [4] Mealling, M., "The IETF XML Registry", draft-mealling-iana-xmlns-registry-05 (work in progress), June 2002. [5] Bray, T., "Extensible Markup Language (XML) 1.0 (Second edition)", W3C REC REC-xml-20001006, October 2000. [6] Day, M., "A model for presence and instant messaging", RFC 2778, February 2000. [7] Rosenberg, J., "Session Initiation Protocol (SIP) Extensions for Presence", draft-ietf-simple-presence-10.txt (work in progress), January 2003. [8] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. [9] Peterson, J., "Common profile for presence (CPP)", draft-ietf-impp-pres-03.txt (work in progress), May 2003. [10] Schulzrinne, H., "RPID -- Rich Presence Information Data Format", draft-ietf-simple-rpid-00.txt (work in progress), July 2003. [11] Schulzrinne, H., "CIPID: Contact Information in Presence Information Data Format", draft-ietf-simple-cipid-00.txt (work Isomaki & Leppanen Expires April 2, 2004 [Page 8] Internet-Draft XCAP Usage for Presence Publishing October 2003 in progress), August 2003. [12] Campbell, B., "SIMPLE Presence Publication Requirements", draft-ietf-simple-publish-reqs-00 (work in progress), February 2003. [13] Niemi, A., "Session Initiation Protocol (SIP) Extension for Event State Publication", draft-ietf-sip-publish-00.txt (work in progress), September 2003. [14] Rosenberg, J., "A Session Initiation Protocol (SIP) Event Package for Modification Events for the Extensible Markup Language (XML) Configuration Access Protocol (XCAP) Managed Documents", draft-rosenberg-simple-xcap-package-00 (work in progress), May 2003. Authors' Addresses Markus Isomaki Nokia Research Center Itamerenkatu 11-13 00180 Helsinki Finland Phone: EMail: markus.isomaki@nokia.com Eva Leppanen Nokia P.O BOX 785 Tampere Finland Phone: EMail: eva-maria.leppanen@nokia.com Isomaki & Leppanen Expires April 2, 2004 [Page 9] Internet-Draft XCAP Usage for Presence Publishing October 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. 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