Krisztian Kiss Internet-Draft Gabor Bajko Network Working Group Nokia Expires: April 25, 2003 October 25, 2002 Requirements for Presence Service based on 3GPP specifications and wireless environment characteristics draft-kiss-simple-presence-wireless-reqs-01.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [1]. 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. The distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This Internet-Draft defines requirements for Presence Service based on 3GPP specifications and wireless environment characteristics. Internet-Draft Expires: April 25, 2002 Page 1 Krisztian Kiss 3GPP Presence Requirements October 2002 Table of contents 1. Introduction.................................................3 2. Conventions used in this document............................3 3. General wireless requirements................................3 4. Publishing requirements......................................4 4.1 Standardized mechanism to publish presence information.......4 4.2 Requirements to support multiple PUAs........................4 4.3 Feedback on publishing.......................................4 4.4 Publishing efficiency........................................5 5. Subscription and notification requirements...................5 5.1 Filtering....................................................5 5.2 Anonymous subscription.......................................5 5.3 Notification efficiency......................................6 5.4 Content indirection..........................................6 6. Requirements for the content of the Presence Document........6 6.1 Presence information elements................................6 6.2 Multivalue concept...........................................7 6.3 Location information.........................................7 7. Authorization requirements...................................7 7.1 Standardized setting of authorization policy.................7 7.2 Expressiveness of authorization rules........................7 8. Watcher information requirements.............................8 8.1 Pending watcher notification.................................8 8.2 Watcher information filtering................................8 8.3 Watcher history..............................................8 9. Presencelist requirements....................................9 10. Security requirements........................................9 11. Evaluation against the SIMPLE charter items..................9 11.1 Publishing and Subscription/Notification requirements........9 11.2 Presence Document requirements...............................9 11.3 Authorization and Management requirements....................9 11.4 Watcher information requirements............................10 12. Proposed next steps.........................................10 Normative References...³³...................................10 ³ Informative References......................................11 Author's addresses..........................................12 A. Acknowledgements............................................12 Full Copyright Statement....................................13 Internet-Draft Expires: April 25, 2002 Page 2 Krisztian Kiss 3GPP Presence Requirements October 2002 1. Introduction This Internet-Draft defines requirements for Presence Service based on 3GPP specifications [23][24] and other needs rising from mobile/wireless environment characteristics. The requirements on the Session Initiation Protocol (SIP) for the Release 5 of the 3GPP IP Multimedia Subsystem are described in [19]. Presence Service is referenced as defined in IMPP Working Group in documents [5] and [6]. This document does not document requirements that have led to the creation and work in progress on a number of SIMPLE WG specifications, i.e. subscriptions and notifications of user presence [7], the SIP presencelist event package [9], the SIP Event Template-Package for Watcher Information documents [11][12], the content indirection mechanism [17] and the SIMPLE Presence Publication Mechanism [15][16]. Rather this document lists only requirements that are additional to those that have led to the mechanisms proposed in these documents. The document also assumes the usage of the Common Presence and Instant Messaging (CPIM) Presence Information Data Format (PIDF) defined in [8] as the default presence document data format, however some of the requirements presented here might require extensions to PIDF. The requirements presented in this document are proposed to be evaluated by the SIMPLE Working Group. The result of this evaluation process would help to determine the work expected to be done in IETF and identify the work which might be done in other standardization bodies, such as 3GPP. Thus, a more precise work-share between standardization bodies could be worked out. The overall goal of these requirements is to allow the development of a fully standardized presence application for wireless terminals, utilizing existing IETF and 3GPP specifications. 2. Conventions used in this document This document does not specify any protocol of any kind. Therefore, the use of the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document, as described in RFC 2119 [2], does not apply. Internet-Draft Expires: April 25, 2002 Page 3 Krisztian Kiss 3GPP Presence Requirements October 2002 3. General wireless requirements The radio interface is a scarce resource. As such, the number and size of the messages exchanged over the radio interface between the UA and the network should be minimized. All the mechanisms developed should make an efficient use of the radio interface. As terminals could be rather small devices, memory requirements, power consumption, processing power, etc. should be kept to a minimum. Mandating support for additional protocols and mechanisms in the terminal must meet this condition. 4. Publishing requirements 4.1 Standardized mechanism to publish presence information There must be a standardized mechanism to manage (publish) the presence information. The standardized publication mechanism must allow publishing from multiple Presence User Agents (PUAs) of a single presentity. It must be possible for the PUAs of the same presentity to add elements to the presence information as well as remove or modify existing elements of the presence information. 4.2 Requirements to support multiple PUAs The Presence Server must be able to merge the information from multiple sources and resolve possible conflicts in the resulting presence document. It must be possible for the PUA to discover the current content and status of the presence document including presence information published by other PUAs belonging to the same presentity. Requirements in section 3 must be also taken into account When fulfiling this requirement. The PUA must be able to manipulate already existing elements of the presence information published by another PUAs. 4.3 Feedback on publishing The PUA must be able to receive feedback about the result of a publishing transaction, the feedback must contain enough information for the principal controlling the presentity to know that the published presence information was successfully composed into the presence document by the Presence Server. Internet-Draft Expires: April 25, 2002 Page 4 Krisztian Kiss 3GPP Presence Requirements October 2002 4.4 Publishing efficiency It must be possible for the presentity to publish multimedia contents along with their communication means when publishing presence information. The mechanism selected for publishing large size content must make efficient use of the network resources and satisfy related requirements in section 3. One identified mechanism to fulfil this requirement is to allow the PUA to update only those parts of the presence information that have changed since the last publication. For example if only some elements of the presence information changes, then only those elements need to be updated as opposed to always sending all the presence information elements within each publish transaction. 5. Subscription and notification requirements 5.1 Filtering It must be possible for a watcher to select certain elements from the presence information that he wants (or does not want) to receive in notifications for. EXAMPLE: the watcher may only want to be notified when the presentity becomes available for conferencing. The Presence Server must be able to construct the presence document to be delivered to the watcher according to the watcher's filtering preferences. NOTE: When determining the elements to be included in the presence document, authorization rules are also needed to be taken into account. It must be possible for the Presence List Server [9] to construct and store appropriate filtering rules for every URI in the presencelist based on the watcher's filtering preferences. [14] describes more detailed filtering requirements. 5.2 Anonymous subscription It must be possible for the watcher to request an anonymous subscription (i.e. the watcher's identifier will not be revealed to the presentity). This anonymous request may be accepted or rejected, depending on the presentity's authorization rules as described in clause 7. NOTE: This requirement may be met with the overall privacy solution for SIP. Internet-Draft Expires: April 25, 2002 Page 5 Krisztian Kiss 3GPP Presence Requirements October 2002 5.3 Notification efficiency It must be possible for the watcher to determine what presence information is available for a particular presentity before fetching or subscribing to the presence information elements with actual values. It must be possible for the watcher to receive notification of multimedia contents along with the presentityÆs communication means. The mechanism selected for notifying large size content must make efficient use of the network resources and satisfy related requirements in section 3. One identified mechanism to fulfil this requirement is to allow the Presence Server to generate partial notifications to the watcher containing only those elements of the presence information, which have changed value compared to the previous notification to the watcher. NOTE: When using this mechanism the watcher must be able to indicate its support for partial notification when subscribing to the presentity's presence information. 5.4 Content indirection Requirements for content indirection are described in [13]. In connection to presence the following requirements have been identified: The Presence Server should be able to perform content indirection. Watchers should have the capability to indicate the support of content indirection. The Presence Server must honor watcher's preferences whether to perform content indirection or not when it detects a situation where content indirection should be performed. 6. Requirements for the content of the presence document 6.1 Presence information elements The presence document must contain presence information elements. Each presence information element must contain a unique identity which makes the presence information element distinguishable from other presence information elements inside the presence document. RFC 2778 [6] defines the presence information element to consist of a STATUS marker, an optional COMMUNICATION ADDRESS, and optional OTHER PRESENCE MARKUP. A COMMUNICATION ADDRESS includes a COMMUNICATION MEANS and a CONTACT ADDRESS. As a further requirement for this definition, it must be possible to define semantics to the content of an element (e.g. for the communication means: voice, video, instant messaging, application). The presence document must be able to contain multiple types of presence information elements. As an example, a presence information element could be user specific, device specific or network specific. Internet-Draft Expires: April 25, 2002 Page 6 Krisztian Kiss 3GPP Presence Requirements October 2002 6.2 Multivalue concept It must be possible to include multiple instances of the semantically same presence information in the presence document. The different instances should contain different values of the same presence information and used to be shown for different watchers. The different watchers must only receive those instances of the presence information they are authorized to by the presentity. EXAMPLE: One group of watchers is shown a different value for the status of presentity than the other. The Presence Server must be able to distinguish whether two presence information elements contain semantically different presence information or they are different instances of the semantically same presence information. 6.3 Geographic location information There must be a standardized mechanism to express geographic location information within the presence document. 7. Authorization requirements This chapter defines the requirements for how presentity is able to authorize the presence subscriptions. 7.1 Standardized setting of authorization policy There must be a standardized mechanism for the presentity (Presence User Agent) to control the authorization policy related to his own presence information. This means that the authorization policy document format and a set of manipulation operations upon that format must be standardized. Such manipulation operations should be aligned with the ones used for other similar purposes (such as conferencing). It should be possible for network operators to extend the format of the authorization policy document and the operations upon that format based on local policy. 7.2 Expressiveness of authorization rules It must be possible for the presentity to set separate authorization rules for different watchers and groups of watchers. With these rules the presentity must be able to override the default behaviour of the presence server for the generation of notifications and content of the notifications. EXAMPLE: Only watchers belonging to a particular group are allowed to receive information related to presentity's location. Internet-Draft Expires: April 25, 2002 Page 7 Krisztian Kiss 3GPP Presence Requirements October 2002 It must be possible for the presentity to manage the authorization rules from multiple sources (e.g. from different terminals of the presentity or by the service provider on behalf of the presentity.) It must be possible for the presentity from one source to learn the changes in the authorization rules changed by other sources belonging to the same presentity. It must be possible for the presentity to grant access rights separately for all elements of the presence information. RFC 2778 [6] defines a model for presence information. Based on this model more specific requirements can be stated: It must be possible for the Presence Server to decide based on authorization rules whether to include a certain tuple in the notification. It must be possible to base that decision on any element in the tuple. In the default case these must include at least TUPLE ID, CONTACT ADDRESS, COMMUNICATION MEANS and STATUS attributes. As a special case, it must be possible for the Presence Server to provide different status values for same COMMUNICATION ADDRESS or combination of COMMUNICATION ADDRESS and OTHER PRESENCE MARKUPs. It must be possible to grant access rights with an expiry time to a particular watcher or group. As groups are seen as an important concept in the authorization policy definition, the solution should be aligned with the operations used for similar purposes (such as conferencing). 8. Watcher information requirements 8.1 Pending watcher notification It must be possible for a presentity to be informed of a pending watcher subscription from a currently unauthorized and/or unknown watcher. 8.2 Watcher information filtering It should be possible for the presentity to monitor the watcher status of certain watchers. NOTE: This requirement may be fulfilled if the watcher information subpackage defined in [11] could be extended with filtering mechanisms. 8.3 Watcher history It must be possible for the presentity to fetch the list of the watchers who have accessed (by subscription or fetch) his presence information during a well-defined time-period (e.g. last 7 days). Internet-Draft Expires: April 25, 2002 Page 8 Krisztian Kiss 3GPP Presence Requirements October 2002 Additionally to the list of watchers, the details of the presence information provided to different watchers should be available for the presentity when fetching the watcher history. 9. Presencelist requirements Requirements for creating a presencelist, adding new URIs to an existing presencelist, modifying or removing existing URIs from an existing presencelist, or deleting a presencelist are described in [10]. 10. Security requirements Security requirements assume requirements that have led to existing security mechanism described in [18]. Further security requirements over and above this have not yet been identified. 11. Evaluation against the SIMPLE charter items SIMPLE Working Group charter may contain solution space for some of the requirements presented in this document. This chapter will present a proposal how these requirements could be mapped into SIMPLE Working Group work items. 11.1 Publishing and Subscription/Notification requirements The most appropriate place to implement all publishing and subscription/notification related requirements is the SIMPLE Working Group, as SIP based presence extensions have been specified in this Working Group. At the moment there is no appropriate work item for these requirements. 11.2 Presence Document requirements New SIMPLE charter has a work item for SIMPLE PIDF profile. Scope of this work item could be defined to include presence document requirements presented in this document. 11.3 Authorization and Management requirements New SIMPLE charter has a work item for user's presencelist management and authorization operations. This work item could be used to define generic approach how user's presence service related information could be managed and how to implement authorization requirements presented in this document. Internet-Draft Expires: April 25, 2002 Page 9 Krisztian Kiss 3GPP Presence Requirements October 2002 11.4 Watcher information requirements Watcher information format and event-template has been specified in SIMPLE Working Group. It would be beneficial if this group's expertise could be utilized to generate required extensions to support watcher information filtering and history information. 12. Proposed next steps It is proposed that SIMPLE Working Group should evaluate these requirements. The requirements for which a consensus is found within the Working Group should be incorporated into the presence requirements Working Group draft. It is also expected for the Working Group to point out any requirements that fall out of its scope, so that other standardization bodies, such as 3GPP are able to start working on those without the risk of overlapping work. The results of such work can be brought back to IETF as Informational documents. Normative References 1. S. Bradner, "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. 2. S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 3. J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler: "SIP, Session Initiation Protocol", RFC 3261, June 2002 4. A. Roach, "ession Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002 5. M. Day, S. Aggarwal, G. Mohr, J. Vincent "Instant Messaging / Presence Protocol Requirements", RFC 2779 6. M. Day, J. Rosenberg, H. Sugano, "A Model for Presence and Instant Messaging", RFC 2778 7. J. Rosenberg et al., "SIP Extensions for Presence", draft-ietf- simple-presence-07.txt, May 2002, work in progress 8. H. Sugano, S. Fujimoto, G. Klyne, A. Bateman: "CPIM Presence Information Data Format", draft-ietf-impp-cpim-pidf-05.txt, May 2002, work in progress 9. J. Rosenberg, B. Campbell, "SIP Event Package for List Presence", draft-ietf-simple-presencelist-package-00.txt, June 2002, work in progress Internet-Draft Expires: April 25, 2002 Page 10 Krisztian Kiss 3GPP Presence Requirements October 2002 10. J. Rosenberg, M. Isomaki, "Requirements for Manipulation of Data Elements in SIMPLE Systems", draft-ietf-simple-data-req-00.txt, October 2002, work in progress 11. J. Rosenberg, "A Session Initiation Protocol (SIP) Event Template-Package for Watcher Information", draft-ietf-simple- winfo-package-02.txt, May 2002, work in progress 12. J. Rosenberg, "An Extensible Markup Language (XML) Based Format for Watcher Information", draft-ietf-simple-winfo-format-02.txt, May 2002, work in progress 13. S. Olson, "Requirements for Content Indirection in SIP Messages", draft-ietf-sipping-content-indirect-02.txt, September 2002, work in progress 14. T. Moran, S. Addagatla, "Requirements for Event Notification Filters", draft-moran-sipping-filter-reqs-00.txt, October 2002, work in progress 15. B. Campbell, S. Olson, J. Peterson, J. Rosenberg, B. Stucker, "SIMPLE Presence Publication Mechanism", draft-olson-simple-publish-00, June 2002, work in progress 16. A. Niemi, "SIP Specific Data Publication Framework", draft-niemi-simple-publish-framework-00, September2002, work in progress 17. S. Olson, "A Mechanism for Content Indirection in SIP Messages", draft-olson-sip-content-indirect-mech-01, August 2002, work in progress 18. J. Arkko, V. Torvinen, G. Camarillo, T. Haukka, S. Sen, "Security Mechanism Agreement for SIP Sessions", draft-ietf-sip-sec-agree-04.txt, June 2002, work in progress 19. M. Garcia-Martin, "3rd-Generation Partnership Project (3GPP) Release 5 requirements on the Session Initiation Protocol (SIP), draft-ietf-sipping-3gpp-r5-requirements-00.txt, October 2002, work in progress Informative References 20. 3GPP TS 23.228 "IP Multimedia Subsystem (IMS) (Stage 2) - Release 5", Version 5.6.0 available at ftp://ftp.3gpp.org/specs/latest/Rel-5/23_series/ 21. 3GPP TS 24.228: "Signaling flows for the IP Multimedia call control based on SIP and SDP", Version 5.2.0 available at ftp://ftp.3gpp.org/specs/archive/24_series/24.228/ Internet-Draft Expires: April 25, 2002 Page 11 Krisztian Kiss 3GPP Presence Requirements October 2002 22. 3GPP TS 24.229: "IP Multimedia Call Control Protocol based on SIP and SDP, stage 3", Version 5.2.0 available at ftp://ftp.3gpp.org/specs/archive/24_series/24.229/ 23. 3GPP TS 22.141: "Presence Service, Stage 1", Version 5.2.0 available at ftp://ftp.3gpp.org/specs/archive/22_series/22.141/ 24. 3GPP TS 23.141: "Presence Service, Architecture and Functional Description, Stage 2", Version 0.2.1 available at ftp://ftp.3gpp.org/specs/archive/23_series/23.141/ Authors' addresses Krisztian Kiss Nokia P.O. Box 100 FIN-33721 Tampere, Finland Tel: +358 50 4835363 e-mail: krisztian.kiss@nokia.com Gabor Bajko Nokia HU-1092 Budapest, Koztelek 6 Hungary Tel: +36 20 9849259 e-mail: gabor.bajko@nokia.com Appendix A. Acknowledgements The authors would like to thank the following people for their interest, support and efforts when writing this Internet-Draft: Markus Isomaki (Nokia), Mikko Lonnfors (Nokia), Juha Kalliokulju (Nokia), Eva-Maria Leppanen (Nokia), Georg Mayer (Siemens), Mark Beckmann (Siemens), Sonia Garapaty (Nortel), Jayshree Bharatia (Nortel), Keith Drage (Lucent), Andrew Allen (DynamicSoft), Kevan Hobbis (H3G), Harmand Alexandre (mmO2), Duncan Mills (Vodafone), Miguel A. Garcia (Ericsson), Milo Orsic (Lucent). Although not an official communication of the 3GPP, this document has been discussed and commented by a number of delegates in the relevant 3GPP working groups. Internet-Draft Expires: April 25, 2002 Page 12 Krisztian Kiss 3GPP Presence Requirements October 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. 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