SIMPLE WG Ashir Ahmed Internet Engineering Task Force Ginga Kawaguchi Internet Draft Satoshi Tokuno NTTCommunications Shinji Okumura SoftFront draft-ashir-simple-message-guideline-00.txt February 9, 2004 Expires: August, 2004 A guideline on message headers and URI in SIP/SIMPLE framework 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 To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Abstract: SUBSCRIBE, NOTIFY and PUBLISH methods in SIP are responsible for carrying presence information to a target destination. Message headers (Request-line, To, From, Contact etc.) indicate SIP entities that are identified by a URI. This document clarifies the indication of the message headers and provides a guideline on URI usage in the header fields. The authors hope that this document will be useful for SIP/SIMPLE implementers, interoperability testers, designers, and protocol researchers. 1. Introduction Presence information conveys the ability and willingness of a user to communicate across a set of elements. RFC 2778 [ref] defines a model and terminology for describing systems that provide presence information. A.Ahmed, et. al. [Page 2] Internet Draft URI Usage guideline Februrary 09, 2004 Presence service in that model is a system that accepts, stores, and distributes presence information of a presentity (presence information owner) to interested parties, called watchers. SUBSCRIBE [ref], NOTIFY [ref] and PUBLISH[ref] have been introduced to carry these presence information. The message headers (Request-line, To, From and Contact etc) in these methods indicate the elements involved in the transportation process. Not all the headers are necessary to be understood by the elements. A common understanding about the header fields and the URI scheme will be useful for interoperability testing, SIP/SIMPLE implementations and in designing protocols. This document clarifies what exactly the message headers indicate and provides a guideline on URI usage. A SIP/SIMPLE message flow example is also shown. 2. URIs in SIP/SIMPLE This section describes the URIs used in SIP/SIMPLE framework and also introduces the recommendations which URI should be used in representing what resoruces or element. URI: SIP-URI,SIPS-URI,Pres-URI and IM-URI explanations about these URIs and their usage will be written later. 3. Methods, Message headers and URI usages This section provides a brief description about the Methods used in presence protocol, introduces the major header fields that are responsible for carrying presence information. 3.2 Headers, indications and URI usage Request-URI shows the URI that appears in the request-line of SIP message. (To, From, Contact)-URI indecates the respective fields in SIP. Some common tips: -Only Request-URI is used to transfer presence information. -SIP Proxies (or any other agents) MUST NOT use To: header to determine message transfer location as this header will not be read by any other SIP elements on the fly. -Contact-URI is used only as a return-message recipient. -From-URI MUST NOT be considered as any notification or replication entity. Other fields are written below: 3.2.1 SUBSCRIBE: Request-URI: indicates the presence resource. Usually this resource is identified by a presence URI, which is in the form of pres:resource@example.com. SIP or SIPS URI can also be used. To-URI: indicates the logical recipient of the request (i.e. the pres URI of the resource (e.g. pres:resource@example.com). SIP or SIPS URI can also be used. From-URI: indicates the subscriber itself. A SIP or SIPS URI can be used to identify the subscriber (e.g. sip:user@example.com). Contact-URI: indicates the subscriber's contact address where the subscriber can be reached at (e.g. sip:user@watcherhost.example.com). A.Ahmed, et. al. [Page 3] Internet Draft URI Usage guideline Februrary 09, 2004 3.2.2 NOTIFY: NOTIFY is a response to the SUBSCRIBE request. Some headers are copied from the SUBSRIBE request to identify the subscriber and the intermediate entities, if any. Request-URI: indicates the subscriber of the request and is identified by the Contact-URI of SUBSCRIBE request (e.g. sip:user@watcherhost.example.com). To-URI: indicates the subscriber's logical identity and is identified by the From-URI of SUBSCRIBE request (e.g. sip:user@example.com) From-URI : indicates the notifier or the To-URI of SUBSCRIBE request (e.g. pres:resource@example.com) Contact-URI : indicates the Contact address of the presence server (e.g. sip.server.example.com). 3.2.3 PUBLISH: Request-URI: indicates a presence resource to be published. Usually a pres-URI (e.g. pres:resource@example.com) of the presentity is used for identification. To-URI: indicates the presence resource. Usually a pres-URI is used for identification. From-URI: indicates the presentity. A SIP or SIPS URI is used. Contact: optional 4. Message flow example 4.1 A simple example This example contains the minimum set of elements. Description of these elements are defined in RFC 2778 [ref] and explained in several IETF drafts. Element Display Name URI/FQDN IP Address PUA bobüfs PUA sip:bob@example.com 10.0.0.2 pua.example.com PA sip:pa@example.com 10.0.0.3 A.Ahmed, et. al. [Page 4] Internet Draft URI Usage guideline Februrary 09, 2004 pa.example.com Watcher Alice sip:alice@example.com 10.0.0.1 wua.example.com Proxy sip:proxy.example.com 10.0.0.4 proxy.example.com This message flow illustrates how a PUA uploads presence information to the presence server (PA) by using PUBLISH; a WATCHER (Alice) sends a SUBSCRIBE request to know Bobüfs presence state. This flow assumes that the watcher and the PUA have previously been authorized to upload and subscribe to this resource at the server. This is also assumed that all the messages go through the proxy. PUA PA PROXY WATCHER (EPA) (ESC) (REGISTRAR) | | | | | |--R1: REGISTER-->| | | | | | | |<-R2: 200 OK-----| | | | | | | | |<---M1: SUBSCRIBE---| | |<-M2: SUBSCRIBE--| | | | | | | |--M3: 200 OK---->| | | | |----M4: 200 OK----->| | |--M5: NOTIFY---->| | | | |----M6: NOTIFY----->| | | | | | | |<---M7: 200 OK------| | |<-M8: 200 OK-----| | | | | | | | | | | | | | |--M9: PUBLISH->| | | | | | | | |<-M10: PUBLISH---| | | | | | | |--M11: 200 OK--->| | | | | | |<-M12 200 OK---| | | | | | | | |--M13: NOTIFY--->| | A.Ahmed, et. al. [Page 5] Internet Draft URI Usage guideline Februrary 09, 2004 | | |----M14: NOTIFY---->| | | | | | | |<---M15: 200 OK-----| | |<-M16: 200 OK----| | | | | | It is assumed that the AoR of bob as pres:bob@example.com in registered in the proxy. R1: REGISTER REGISTER sip:example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa0 Max-Forwards: 70 To: From: ;tag=456248 Call-ID: 843817637684230@pa.example.com CSeq: 1 REGISTER Contact: Expires: 7200 Content-Length: 0 R2: 200 OK SIP/2.0 200 OK Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa0 To: ;tag=2493k59kd From: ;tag=456248 Call-ID: 843817637684230@pa.example.com CSeq: 1 REGISTER Contact: Expires: 7200 Content-Length: 0 M1: SUBSCRIBE SUBSCRIBE pres:bob@example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.1:5060;branch=z9hG4bKwatcher1 To: From: ;tag=123456 Call-ID: 12345678@wua.example.com CSeq: 1 SUBSCRIBE Max-Forwards: 70 Expires: 3600 Event: presence Contact: Content-Length: 0 A.Ahmed, et. al. [Page 6] Internet Draft URI Usage guideline Februrary 09, 2004 M2: SUBSCRIBE SUBSCRIBE pres:bob@pa.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy1 Via: SIP/2.0/UDP 10.0.0.1:5060;branch=z9hG4bKwatcher1 To: From: ;tag=123456 Call-ID: 12345678@wua.example.com CSeq: 1 SUBSCRIBE Max-Forwards: 69 Expires: 3600 Event: presence Record-Route: Contact: Content-Length: 0 M3: 200 OK SIP/2.0 200 OK Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy1 Via: SIP/2.0/UDP 10.0.0.1:5060;branch=z9hG4bKwatcher1 To: ;tag=234567 From: ;tag=123456 Call-ID: 12345678@wua.example.com CSeq: 1 SUBSCRIBE Expires: 3600 Record-Route: Contact: Content-Length: 0 M4: 200 OK SIP/2.0 200 OK Via: SIP/2.0/UDP 10.0.0.1:5060;branch=z9hG4bKwatcher1 To: ;tag=234567 From: ;tag=123456 Call-ID: 12345678@wua.example.com CSeq: 1 SUBSCRIBE Expires: 3600 Record-Route: Contact: Content-Length: 0 M5: NOTIFY NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa1 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 1 NOTIFY Max-Forwards: 70 A.Ahmed, et. al. [Page 7] Internet Draft URI Usage guideline Februrary 09, 2004 Route: Contact: Event: presence Subscription-State: active; expires=3599 Content-Type: application/pidf+xml Content-Length: ... open 2003-02-01T16:49:29Z open 2003-02-01T12:21:29Z M6: NOTIFY NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy2 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa1 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 1 NOTIFY Max-Forwards: 69 Record-Route: Contact: Event: presence Subscription-State: active; expires=3599 Content-Type: application/pidf+xml Content-Length: ... open 2003-02-01T16:49:29Z A.Ahmed, et. al. [Page 8] Internet Draft URI Usage guideline Februrary 09, 2004 open 2003-02-01T12:21:29Z M7: 200 OK NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy2 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa1 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 1 NOTIFY Record-Route: Contact: Content-Length: 0 M8: 200 OK NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa1 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 1 NOTIFY Record-Route: Contact: Content-Length: 0 M9: PUBLISH PUBLISH pres:bob@example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.2:5060;branch=z9hG4bKpua1 To: From: ;tag=1234wxyz Call-ID: 81818181@pua.example.com CSeq: 1 PUBLISH Max-Forwards: 70 Expires: 3600 Event: presence Content-Type: application/pidf+xml Content-Length: ... A.Ahmed, et. al. [Page 9] Internet Draft URI Usage guideline Februrary 09, 2004 closed 2003-02-01T17:00:19Z M10: PUBLISH PUBLISH pres:bob@pa.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy3 Via: SIP/2.0/UDP 10.0.0.2:5060;branch=z9hG4bKpua1 To: From: ;tag=1234wxyz Call-ID: 81818181@pua.example.com CSeq: 1 PUBLISH Max-Forwards: 69 Expires: 3600 Event: presence Content-Type: application/pidf+xml Content-Length: ... closed 2003-02-01T17:00:19Z M11: 200 OK SIP/2.0 200 OK Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy3 Via: SIP/2.0/UDP 10.0.0.2:5060;branch=z9hG4bKpua1 To: ;tag=abcd5678 From: ;tag=1234wxyz Call-ID: 81818181@pua.example.com CSeq: 1 PUBLISH Content-Length: 0 M12: 200 OK SIP/2.0 200 OK Via: SIP/2.0/UDP 10.0.0.2:5060;branch=z9hG4bKpua1 To: ;tag=abcd5678 From: ;tag=1234wxyz A.Ahmed, et. al. [Page 10] Internet Draft URI Usage guideline Februrary 09, 2004 Call-ID: 81818181@pua.example.com CSeq: 1 PUBLISH Content-Length: 0 M13: NOTIFY NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa2 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 2 NOTIFY Max-Forwards: 70 Route: Contact: Event: presence Subscription-State: active; expires=3400 Content-Type: application/pidf+xml Content-Length: ... closed 2003-02-01T17:00:19Z open 2003-02-01T12:21:29Z M14: NOTIFY NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy4 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa2 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 2 NOTIFY Max-Forwards: 69 Record-Route: Contact: Event: presence A.Ahmed, et. al. [Page 11] Internet Draft URI Usage guideline Februrary 09, 2004 Subscription-State: active; expires=3400 Content-Type: application/pidf+xml Content-Length: ... closed 2003-02-01T17:00:19Z open 2003-02-01T12:21:29Z M15: 200 OK NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.4:5060;branch=z9hG4bKproxy4 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa2 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 2 NOTIFY Record-Route: Contact: Content-Length: 0 M16: 200 OK NOTIFY sip:alice@wua.example.com SIP/2.0 Via: SIP/2.0/UDP 10.0.0.3:5060;branch=z9hG4bKpa2 To: ;tag=123456 From: ;tag=234567 Call-ID: 12345678@wua.example.com CSeq: 2 NOTIFY Record-Route: Contact: Content-Length: 0 A.Ahmed, et. al. [Page 12] Internet Draft URI Usage guideline Februrary 09, 2004 4.2 An example with presence related functions TBD. An example with Filter function, RLS etc will be described. 5. Security Consideration 6. References 6.1 Normative Reference [1] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. [2] Rosenberg, J., "A Presence Event Package for the Session Initiation Protocol (SIP)", draft-ietf-simple-presence-10 (work in progress), January 2003. [3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. 6.2 Informative References [4] Campbell, B., "SIMPLE Presence Publication Requirements", draft-ietf-simple-publish-reqs-00 (work in progress), February 2003. [5] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9, RFC 959, October 1985. [6] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [7] Rosenberg, J., "A Presence Event Package for the Session Initiation Protocol (SIP)", draft-ietf-simple-presence-10 (work in progress), January 2003. [8] Sugano, H. and S. Fujimoto, "Presence Information Data Format (PIDF)", draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003. 2.1 Methods:SUBSCRIBE:NOTIFY:PUBLISH: A.Ahmed, et. al. [Page 13] Internet Draft URI Usage guideline Februrary 09, 2004 7. Authors' Addresses Ashir Ahmed NTTCommunications Inc. 3-20-2 Nishi-Shinjuku Shinjuku-ku, Tokyo 163-1421 JAPAN Phone: +81 3 6800 3029 EMail: a.ahmed@ntt.com Ginga Kawaguti NTTCommunications Inc. 3-20-2 Nishi-Shinjuku Shinjuku-ku, Tokyo 163-1421 JAPAN Phone: +81 3 6800 3032 EMail: g.kawaguti@ntt.com Satoshi Tokuno NTTCommunications Inc. 3-20-2 Nishi-Shinjuku Shinjuku-ku, Tokyo 163-1421 JAPAN Phone: +81 3 6800 3031 EMail: s.tokuno@ntt.com Shinji Okumura SoftFront 3F Sapporo IT Front Bldg., 28-196, Kita-9, Nishi-15, Chuo-ku, Sapporo 060-0009 JAPAN Tel: +81-11-623-1001 EMail:shin@softfront.co.jp 8. 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 A.Ahmed, et. al. [Page 14] Internet Draft URI Usage guideline Februrary 09, 2004 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. Copies of claims of rights made available for publication 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 implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. 9. Full Copyright Statement Copyright (C) The Internet Society (2004). All Rights Reserved. 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