Internet Engineering Task Force Krisztian Kiss Gabor Bajko Internet_Draft Nokia SIMPLE Working Group draft-kiss-simple-presence-wireless-reqs-00.txt June 21, 2002 Expires: December 2002 Requirements for Presence Service based on 3GPP specifications and wireless environment characteristics 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. 1. Abstract This Internet-Draft defines requirements for Presence Service based on 3GPP specifications and wireless environment characteristics. The requirements presented in this document are proposed to be evaluated by the SIMPLE Working Group. The result of this evaluation process could help to determine the work expected to be done in IETF and identify the work which might be done in other standardization Internet-Draft Expires: December 11, 2002 Page 1 Krisztian Kiss 3GPP Presence Requirements June 2002 bodies, such as 3GPP. Thus, a more precise work-share between standardization bodies could be worked out. 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. 3. Table of contents Status of this Memo...............................................1 1. Abstract.......................................................1 2. Conventions used in this document..............................2 3. Table of contents..............................................2 4. Introduction...................................................2 5. General wireless requirements..................................3 6. Publishing requirements........................................3 6.1 Standardized mechanism to update (publish) presence information3 6.2 Publishing efficiency.........................................4 7. Subscription and notification requirements.....................4 7.1 Filtering.....................................................4 7.2 Anonymous subscription........................................4 7.3 Efficient subscription and notification.......................4 7.4 Content indirection...........................................5 8. Requirements for the content of the Presence Document..........5 8.1 Presence attributes...........................................5 8.2 Location information..........................................5 9. Authorization requirements.....................................6 9.1 Standardized setting of authorization policy..................6 9.2 Expressiveness of authorization rules.........................6 10. Watcher information requirements..............................6 10.1 Watcher information filtering................................6 10.2 Watcher history..............................................7 11. Evaluation against the SIMPLE charter items...................7 11.1 Publishing requirements......................................7 11.2 Subscription and notification requirements...................7 11.3 Presence Document requirements...............................7 11.4 Authorization requirements...................................7 11.5 Watcher information requirements.............................8 12. Proposed next steps...........................................8 13. Author's addresses............................................8 14. Contributors..................................................8 15. References....................................................8 Full Copyright Statement.........................................10 4. Introduction Internet-Draft Expires: December 6, 2002 Page 2 Krisztian Kiss 3GPP Presence Requirements June 2002 This Internet-Draft defines requirements for Presence Service based on 3GPP specifications [6][7] and other needs rising from mobile/wireless environment characteristics. Presence Service is referenced as defined in IMPP Working Group in documents [10] and [11]. The document assumes the usage of Session Initiation Protocol (SIP) [8] for subscriptions and notifications of user presence [12] as defined in the SIMPLE Working Group. Additionally, some other existing Working Group and/or individual drafts are used as a baseline. These include the SIP Event Template-Package for Watcher Information documents [16][17], the SIMPLE components draft [15], the SIP buddylist event package [14] and the content indirection requirements draft [18]. The document also assumes the usage of the Common Presence and Instant Messaging (CPIM) Presence Information Data Format (PIDF) defined in [13] 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. 5. 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 requirement. 6. Publishing requirements 6.1 Standardized mechanism to update (publish) presence information Internet-Draft Expires: December 6, 2002 Page 3 Krisztian Kiss 3GPP Presence Requirements June 2002 There must be a standardized mechanism to update (publish) the presence information. The mechanism must allow publishing from multiple Presence User Agents (PUAs) of a single presentity. There must be rules and mechanisms to merge the information from multiple sources and resolve possible conflicts, and to keep all the publishing PUAs aware of each other's published information. 6.2 Publishing efficiency The preferred mechanism for updating the presence information would allow the Presence User Agent to update only parts of the presence information. For example if a piece of presence information changes, only that part needs to be updated, as opposed to always sending the full state within each publish transaction. This would allow more efficient utilization of the network resources. See also the related requirements in section 5. 7. Subscription and notification requirements 7.1 Filtering It must be possible for a subscriber to request what presence information he wants to receive in future notifications. EXAMPLE: the subscriber may only want to be notified when the presentity becomes available for conferencing. The Presence Agent must be able to construct presence information that is delivered to subscriber according to authorization rules and subscriberÆs filtering request. 7.2 Anonymous subscription It must be possible for the subscriber to request an anonymous subscription (i.e. the subscriberÆs identifier will not be revealed to the presentity). This anonymous request may be accepted or rejected, depending on the presentityÆs access control settings, as described in Chapter 9. NOTE: This requirement may be met with the overall privacy solution for SIP. 7.3 Efficient subscription and notification The preferred mechanism would allow the Presence Agent to generate partial notifications containing only those attributes, which have changed value compared to the previous notification. Internet-Draft Expires: December 6, 2002 Page 4 Krisztian Kiss 3GPP Presence Requirements June 2002 The mechanism would also allow the subscriber to indicate support for partial notification when subscribing to the presentityÆs presence information. Another identified way to decrease the number of SUBSCRIBE and NOTIFY messages is to use a solution similar to the SIP event package for buddylist subscriptions described in [19]. A third identified solution is to use some dynamic compression mechanisms to compress the presence information. See the related requirements in section 5. 7.4 Content indirection Content indirection is described in [18]. In connection to presence the following requirements have been identified: The Presence Agent must be able to perform content indirection. Subscribers must have the capability to indicate the support of content indirection. The Presence Agent must honor subscriberÆs preferences whether to perform content indirection or not when it detects a situation where content indirection should be performed. 8. Requirements for the content of the Presence Document It must be possible for the Presence Document to contain multiple types of presence attributes. As an example, one type could be user specific attribute, another type device specific attribute and a third type network specific attribute. 8.1 Presence attributes It must be possible for the Presence Document to identify the type of presence attribute and must provide unique identity for all presence attributes. It must be possible to have multiple instances of the semantically same attributes for different purposes/subscribers. EXAMPLE: One group of subscribers is shown a different value for the status of presentity than the other. 8.2 Location information There must be a standardized mechanism to express location information and related privacy restrictions within the Presence Document. This location information may be transported either in a standardized way or by a 3GPP specific extension to the standardized Presence Document. Internet-Draft Expires: December 6, 2002 Page 5 Krisztian Kiss 3GPP Presence Requirements June 2002 9. Authorization requirements This chapter defines the requirements for how presentity is able to authorize the presence subscriptions. 9.1 Standardized setting of authorization policy There must be a standardized mechanism for the presentity (Presence User Agent) to set 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. 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. 9.2 Expressiveness of authorization rules It must be possible to define different "access rights" or "views" for different subscribers or groups of subscribers. The access rights determine what parts of the presence information are provided to a particular subscriber. EXAMPLE: Only subscribers belonging to a particular group are allowed to receive information related to presentity's location. It must be possible for the presentity to grant access rights separately for all elements of the presence information. It must be possible for the presentity to grant access rights separately on the level of detail of the presence information. It must be possible to grant access rights with an expiry time to a particular subscriber or group. As groups are seen as an important concept in the authorization policy definition, it is expected that the standardized mechanisms related to authorization policy management include operations for management of groups. The solution should be aligned with the group management operations used for other purposes. 10. Watcher information requirements 10.1 Watcher information filtering Internet-Draft Expires: December 6, 2002 Page 6 Krisztian Kiss 3GPP Presence Requirements June 2002 It should be possible for the presentity to monitor the watcher status of certain subscribers. This requirement may be fulfilled if the watcher information subpackage defined in [16] could be extended with filtering mechanisms. 10.2 Watcher history It must be possible for the presentity to fetch the list of the subscribers who have accessed (by subscription or fetch) his presence information during a well-defined time-period (e.g. last 7 days). Additionally to the list of subscribers, the details of the presence information provided to different subscribers should be available for the presentity when fetching the watcher history. 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 requirements New SIMPLE charter has a work item for userÆs buddylist management and authorization operations. This work item could be used to define generic approach how userÆs presence service related information could be managed. 11.2 Subscription and notification requirements The most appropriate place to implement all subscription and 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. 11.3 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. 11.4 Authorization requirements New SIPMLE charter has a work item for userÆs buddylist management and authorization operations. This work item could be used to implement authorization requirements presented in this document. Internet-Draft Expires: December 6, 2002 Page 7 Krisztian Kiss 3GPP Presence Requirements June 2002 11.5 Watcher information requirements Watcher information format and event-template has been specified in SIMPLE Working Group. It would be beneficial if this groupÆs 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. 13. Author's addresses Krisztian Kiss Nokia Research Center 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 14. Contributors The following people contributed to this draft: Markus Isom„ki(Nokia), Mikko L÷nnfors (Nokia), Georg Mayer (Siemens), Mark Beckmann (Siemens), Sonia Garapaty (Nortel), Jayshree Bharatia (Nortel), Keith Drage (Lucent), Andrew Allen (DynamicSoft), Kevan Hobbis (H3G), Sunil Chotai (mmO2), Duncan Mills (Vodafone), Miguel A. Garcia (Ericsson). 15. References Internet-Draft Expires: December 6, 2002 Page 8 Krisztian Kiss 3GPP Presence Requirements June 2002 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. 3GPP TS 23.228 "IP Multimedia Subsystem (IMS) (Stage 2) - Release 5", Version 5.5.0 available at ftp://ftp.3gpp.org/specs/latest/Rel-5/23_series/ 4. 3GPP TS 24.228: "Signaling flows for the IP Multimedia call control based on SIP and SDP", Version 5.1.0 available at ftp://ftp.3gpp.org/specs/archive/24_series/24.228/ 5. 3GPP TS 24.229: "IP Multimedia Call Control Protocol based on SIP and SDP, stage 3", Version 5.1.0 available at ftp://ftp.3gpp.org/specs/archive/24_series/24.229/ 6. 3GPP TS 22.141: "Presence Service, Stage 1", Version 5.2.0 available at ftp://ftp.3gpp.org/specs/archive/22_series/22.141/ 7. 3GPP TR 23.841: "Presence Service, Architectural and Functional Description, Stage 2", Version 1.0.0 available at ftp://ftp.3gpp.org/specs/archive/23_series/23.841/ 8. J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler: "SIP, Session Initiation Protocol", draft-ietf-sip-rfc2543bis-09.txt, February 2002, work in progress. 9. A. Roach, "SIP-Specific Event Notification", draft-ietf-sip- events-05.txt, February 2002, work in progress 10. M. Day, S. Aggarwal, G. Mohr, J. Vincent "Instant Messaging / Presence Protocol Requirements", RFC 2779 11. M. Day, J. Rosenberg, H. Sugano, "A Model for Presence and Instant Messaging", RFC 2778 12. J. Rosenberg et al., "SIP Extensions for Presence", draft-ietf- simple-presence-07.txt, May 2002, work in progress 13. 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 14. J. Rosenberg, B. Campbell, "SIP Event Package for Buddy List Presence", draft-rosenberg-simple-buddylist-package-00.txt, November 2001, work in progress 15. J. Rosenberg, "A Component Model for SIMPLE", draft-rosenberg- simple-components-00.txt, February 2002, work in progress Internet-Draft Expires: December 6, 2002 Page 9 Krisztian Kiss 3GPP Presence Requirements June 2002 16. 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 17. J. Rosenberg, "An Extensible Markup Language (XML) Based Format for Watcher Information", draft-ietf-simple-winfo-format-02.txt, May 2002, work in progress 18. S. Olson, "Requirements for Content Indirection in SIP Messages", draft-olson-sipping-content-indirect-00.txt, March 2002, work in progress 19. J. Rosemberg, "A SIP Event Package for Buddylist Presence", draft-rosenberg-simple-buddylist-package-00.txt, November 2001, work in progress (expired) Full Copyright Statement "Copyright (C) The Internet Society (2000). All Rights Reserved. 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