SIPPING Working Group G. Camarillo Internet-Draft Ericsson Expires: September 25, 2004 A. Roach dynamicsoft March 27, 2004 Subscriptions to Ad-Hoc Resource Lists in the Session Initiation Protocol (SIP) draft-camarillo-sipping-adhoc-simple-00.txt Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3667. 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 September 25, 2004. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document describes how to create subscriptions to ad-hoc resource lists in SIP. This is done by having the SUBSCRIBE request that requests the creation of the subscription carry a URI list. Camarillo & Roach Expires September 25, 2004 [Page 1] Internet-Draft Ad-Hoc Subscriptions March 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Providing a Resource List Server with a URI List . . . . . . . 3 4. URI List Format . . . . . . . . . . . . . . . . . . . . . . . 4 5. Resource List Server Behavior . . . . . . . . . . . . . . . . 4 6. Resource List Life-Time . . . . . . . . . . . . . . . . . . . 4 7. Providing a URI to Manipulate a Resource List . . . . . . . . 4 8. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 9. Security Considerations . . . . . . . . . . . . . . . . . . . 6 10. Acknowledges . . . . . . . . . . . . . . . . . . . . . . . . . 6 Normative References . . . . . . . . . . . . . . . . . . . . . 6 Informational References . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . 8 Camarillo & Roach Expires September 25, 2004 [Page 2] Internet-Draft Ad-Hoc Subscriptions March 2004 1. Introduction Subscriptions to homogeneous resource lists in SIP [2] are described in [3], which assumes that a resource list (i.e., a list of URIs) is represented by a URI (generally a SIP URI). Once a UA obtains the URI that represents a resource list, it can use the mechanisms described in [3] to subscribe to it. For example, let us assume that the resource list identified by the SIP URI sip:my-friends@example.com contains the following URIs: sip:bill@example.com sip:joe@example.com sip:ted@example.com sip:bob@example.com If a UA subscribes to the presece information of sip:my-friends@example.com, it will obtain the presence information of all the resources in the list. In any case, [3] does not tackle list creation. This document describes a way to create an ad-hoc list with a set of resources, and subscribe to it, using a single SIP request. We use the mechanism to carry URI lists in SIP messages described in [4]. 2. Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119 [1] and indicate requirement levels for compliant implementations. 3. Providing a Resource List Server with a URI List A client that wants to create an ad-hoc resource list and subscribe to it using the mechanism described in this document MUST add a "list" parameter (defined in [4]) to the URI of the resource list and MUST place the resulting URI in the Request-URI of a SUBSCRIBE. The "list" parameter MUST contain a pointer to a URI list that contains the URIs that belong to the resource list. The following is an example of a Request-URI with a "list" parameter. sip:rls@example.com;list="cid:cn35t8jf02@example.com" The client MUST build the remaining of the SUBSCRIBE request Camarillo & Roach Expires September 25, 2004 [Page 3] Internet-Draft Ad-Hoc Subscriptions March 2004 following the rules in [3]. 4. URI List Format As described in [4], the default format for URI lists in SIP is the XCAP resource list format [6]. Still, specific services need to describe which information clients should include in their URI lists, as described in [4]. UAs subscribing to an ad-hoc resource list SHOULD use flat lists (i.e., no hierarchical lists), SHOULD NOT use any entry's attributes but "uri", and SHOULD NOT include any elements inside entries but "display-name" elements. Resource list servers receiving a URI list with more information than what we have just described SHOULD discard all the extra information. 5. Resource List Server Behavior On reception of a SUBSCRIBE with a URI list as described in Section 3, a resource list server MUST follow the rules described in [3] to create the subscription, using the URI list just received as the resource list for the subscription. Once the resource list server has created the subscription, it behaves as a regular resource list server and MUST follow the rules in [3]. Note that the status code in the response to the SUBSCRIBE does not provide any information about whether or not the resource list server was able to succesfully subscribe to the URIs in the URI list. The client obtains this information in the NOTIFIES sent by the server. 6. Resource List Life-Time The life-time of a resource list created as described in Section 5 is blundled to the life-time of the subscription. That is, the resource list SHOULD be destroyed when the subscription expires or is otherwise terminated. 7. Providing a URI to Manipulate a Resource List A client may need to manipulate a resource list at a resource list server. The resource list server MAY provide a URI to manipulate the resource list associated with a subscription using the Call-Info header field [5] in the NOTIFY that establishes the subscription. The "purpose" parameter of the Call-Info header field MUST have a value of "list-management". The following is an example of such a header Camarillo & Roach Expires September 25, 2004 [Page 4] Internet-Draft Ad-Hoc Subscriptions March 2004 field. Call-Info: ;purpose=list-management 8. Example The following is an example of a SUBSCRIBE request, which carries a URI list in its body, sent by a UA to a resource list server. SUBSCRIBE sip:rls@example.com;list=cid:cn35t8jf02@example.com SIP/2.0 Via: SIP/2.0/TCP terminal.example.com;branch=z9hG4bKwYb6QREiCL Max-Forwards: 70 To: RLS From: ;tag=ie4hbb8t Call-ID: cdB34qLToC@terminal.example.com CSeq: 1 SUBSCRIBE Contact: Event: presence Expires: 7200 Supported: eventlist Accept: application/cpim-pidf+xml Accept: application/rlmi+xml Accept: multipart/related Accept: multipart/signed Accept: multipart/encrypted Content-Type: application/resource-lists+xml Content-Length: 315 Content-ID: Figure 1: SUBSCRIBE request Camarillo & Roach Expires September 25, 2004 [Page 5] Internet-Draft Ad-Hoc Subscriptions March 2004 9. Security Considerations TBD 10. Acknowledges Cullen Jennings provided useful comments on this document. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] 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. [3] Roach, A., Rosenberg, J. and B. Campbell, "A Session Initiation Protocol (SIP) Event Notification Extension for Resource Lists", draft-ietf-simple-event-list-04 (work in progress), June 2003. [4] Camarillo, G., "Providing a Session Initiation Protocol (SIP) Application Server with a List of URIs", draft-camarillo-sipping-uri-list-01 (work in progress), February 2004. [5] Khartabil, H., "Conveying a Session Policy Uniform Resource Identifier (URI) in the Session Initiation Protocol (SIP)", draft-khartabil-sip-policy-uri-call-info-purpose-00 (work in progress), February 2004. Informational References [6] Rosenberg, J., "An Extensible Markup Language (XML) Configuration Access Protocol (XCAP) Usage for Presence Lists", draft-ietf-simple-xcap-list-usage-02 (work in progress), February 2004. Camarillo & Roach Expires September 25, 2004 [Page 6] Internet-Draft Ad-Hoc Subscriptions March 2004 Authors' Addresses Gonzalo Camarillo Ericsson Hirsalantie 11 Jorvas 02420 Finland EMail: Gonzalo.Camarillo@ericsson.com Adam Roach dynamicsoft 5100 Tennyson Pkwy Suite 1200 Plano, TX 75024 US EMail: adam@dynamicsoft.com Camarillo & Roach Expires September 25, 2004 [Page 7] Internet-Draft Ad-Hoc Subscriptions March 2004 Intellectual Property Statement 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 IETF's procedures with respect to rights in IETF Documents can be found in BCP 78 and BCP 79. 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