Sipping P. Kyzivat Internet-Draft Cisco Systems, Inc. Expires: January 12, 2006 July 11, 2005 Reg Event Package Extension for GRUUs draft-kyzivat-sipping-gruu-reg-event-02 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 January 12, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This draft defines an extension to RFC 3680 [1] for representing the GRUU associated with a Contact. Kyzivat Expires January 12, 2006 [Page 1] Internet-Draft Reg Event GRUU Extension July 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Description . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Notifier Processing of SUBSCRIBE Requests . . . . . . . . . 3 4. Notifier Generation of NOTIFY Requests . . . . . . . . . . . 3 5. Subscriber Processing of NOTIFY Requests . . . . . . . . . . 4 6. Sample reginfo Document . . . . . . . . . . . . . . . . . . 4 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1 Example: Welcome Notice . . . . . . . . . . . . . . . . . 4 7.2 Example: Implicit Registration . . . . . . . . . . . . . . 5 8. XML Schema Definition . . . . . . . . . . . . . . . . . . . 7 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . 8 10. Security Considerations . . . . . . . . . . . . . . . . . . 8 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 12.1 Normative References . . . . . . . . . . . . . . . . . . 8 12.2 Informative References . . . . . . . . . . . . . . . . . 9 Author's Address . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . 10 Kyzivat Expires January 12, 2006 [Page 2] Internet-Draft Reg Event GRUU Extension July 2005 1. Introduction The addition of GRUU (Globally Routable Unique URI) support to the REGISTER message, defined in [2], introduces another element of state to the registrar. Subscribers to the registration event package [1] will sometimes have need for the new state. For example, the Welcome Notices example in [1] will only operate correctly if the contact address in the reg event notification is reachable by the sender of the welcome notice. When the registering device is using the gruu extension, it is likely that the registered contact address will not be globally addressable, and the gruu should be used as the target address for the MESSAGE. Another case where this feature may be helpful is within the 3GPP IP Multimedia Subsystem (IMS). IMS employs a technique where a REGISTER of a contact address to one Address of Record (AOR) causes the implicit registration of the same contact to other associated AORs. If a GRUU is requested and obtained as part of the registration request, then additional GRUUs will also be needed for the implicit registrations. While assigning the additional GRUUs is straightforward, informing the registering UA of them is not. In IMS, UAs typically subscribe to the 'reg' event, and subscriptions to the 'reg' event for an AOR result in notifications containing registration state for all the associated AORs. The proposed extension provides a way to easily deliver the GRUUs for the associated AORs. The reg event package has provision for including extension elements within the element. This document defines a new element that may be used in that context to deliver the GRUU corresponding to the contact. 2. Description A new element () is defined which contains a GRUU. This optional element is included within the body of a NOTIFY for the "reg" event package when a GRUU is associated with the contact. The contact URI and the GRUU are then both available to the watcher. 3. Notifier Processing of SUBSCRIBE Requests Unchanged from RFC 3680 [1]. 4. Notifier Generation of NOTIFY Requests A notifier for the "reg" event package [1] SHOULD include the Kyzivat Expires January 12, 2006 [Page 3] Internet-Draft Reg Event GRUU Extension July 2005 element when a contact has an Instance ID and a GRUU is associated with the combination of the AOR and the Instance ID. When present, the element MUST be be positioned as an instance of the element within the element. 5. Subscriber Processing of NOTIFY Requests When a subscriber receives a "reg" event notification [1] with a containing a , it SHOULD use the gruu in preference to the corresponding when sending SIP requests to the contact. Subscribers that are unaware of this extension will, as required by [1], ignore the element. 6. Sample reginfo Document The following is an example registration information document including the new element: sip:user@192.0.2.1 "" sip:hha9s8d=-999a@example.com 7. Examples Note: In the following examples the SIP messages have been simplified, removing headers that are not pertinent to the example. 7.1 Example: Welcome Notice Consider the Welcome Notices example in [1]. When the application server receives a notification of a new registration containing the Kyzivat Expires January 12, 2006 [Page 4] Internet-Draft Reg Event GRUU Extension July 2005 reginfo shown in Section 6 it should address messages using the contained GRUU as follows: MESSAGE sip:hha9s8d=-999a@example.com SIP/2.0 To: From: "SIPland Notifier" Content-Type: text/plain Content-Length: ... Welcome to SIPland! Blah, blah, blah. 7.2 Example: Implicit Registration In an 3GPP IMS setting, a UA may send a single register message, requesting assignment of a gruu, as follows: REGISTER sip:example.net SIP/2.0 From: ;tag=4fa3 To: Contact: ;expires=3600 ;+sip.instance="" Supported: path, gruu Content-Length: 0 The response reports success of the registration and returns the GRUU assigned for the combination of AOR, Instance ID, and Contact. It also indicates (via the P-Associated-URI header [5]) that there are two other associated AORs that may have been implicitly registered using the same contact. But each of those implicitly registered AORs will have had a unique GRUU assigned, and there is no way defined to report that assignment in the response. SIP/2.0 200 OK From: ;tag=4fa3 To: Path: Service-Route: Contact: ;expires=3600 ;+sip.instance="" ;gruu="" P-Associated-URI: , Content-Length: 0 Kyzivat Expires January 12, 2006 [Page 5] Internet-Draft Reg Event GRUU Extension July 2005 The UA then subscribes to the 'reg' event package as follows: SUBSCRIBE sip:user_aor_1@example.net SIP/2.0 From: ;tag=31415 To: Route: Event: reg Expires: 3600 Accept: application/reginfo+xml Contact: Content-Length: 0 (The successful response to the subscription is not shown.) Once the subscription is established an initial notification is sent giving registration status. In IMS deployments the response includes, in addition to the status for the requested URI, the status for the other associated URIs. NOTIFY sip:hha9s8d=-999a@example.net SIP/2.0 From: ;tag=31415 To: ;tag=151170 Subscription-State: active;expires=3600 Event: reg Content-Type: application/reginfo+xml Contact: Content-Length: (...) sip:ua.example.com "" sip:hha9s8d=-999a@example.net sip:ua.example.com "" sip:hha9s8d=-999b@example.net sip:ua.example.com "" sip:hha9s8d=-999c@example.net The status indicates that the associated URIs all have the same contact registered. It also includes the unique GRUU that has been assigned to each. The UA may then retain those GRUUs for use when establishing dialogs using the corresponding AORs. 8. XML Schema Definition A gruu document is an XML document that MUST be well-formed and SHOULD be valid. Gruu documents MUST be based on XML 1.0 and MUST be encoded using UTF-8. This specification makes use of XML namespaces for identifying gruu documents. The namespace URI for elements defined for this purpose is a URN, using the namespace identifier 'ietf'. This URN is: urn:ietf:params:xml:ns:gruu Kyzivat Expires January 12, 2006 [Page 7] Internet-Draft Reg Event GRUU Extension July 2005 9. IANA Considerations This section registers a new XML namespace, as per the guidelines in [3]. URI: The URI for this namespace is urn:ietf:params:xml:ns:gruu Registrant Contact: TBD XML: TBD 10. Security Considerations Security considerations for the registration event package is discussed in RFC 3680 [1], and those considerations apply here. The addition of gruu information does not impact security negatively because the gruu is less sensitive than the contact URI itself. 11. Acknowledgements The author would like to thank Jonathan Rosenberg for encouraging this draft. 12. References 12.1 Normative References [1] Rosenberg, J., "A Session Initiation Protocol (SIP) Event Package for Registrations", RFC 3680, March 2004. [2] Rosenberg, J., "Obtaining and Using Globally Routable User Agent (UA) URIs (GRUU) in the Session Initiation Protocol (SIP)", draft-ietf-sip-gruu-03 (work in progress), February 2005. [3] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. Kyzivat Expires January 12, 2006 [Page 8] Internet-Draft Reg Event GRUU Extension July 2005 12.2 Informative References [4] 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. [5] Garcia-Martin, M., Henrikson, E., and D. Mills, "Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP)", RFC 3455, January 2003. [6] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, "Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)", RFC 3840, August 2004. Author's Address Paul H. Kyzivat Cisco Systems, Inc. 1414 Massachusetts Avenue Boxborough, MA 01719 USA Email: pkyzivat@cisco.com Kyzivat Expires January 12, 2006 [Page 9] Internet-Draft Reg Event GRUU Extension July 2005 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 procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Kyzivat Expires January 12, 2006 [Page 10]