SIPPING Working Group G. Camarillo Internet-Draft Ericsson Expires: May 23, 2004 November 23, 2003 Requirements for Session Initiation Protocol (SIP) Exploder Invocation draft-camarillo-sipping-exploders-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. 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 May 23, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document describes the need for SIP exploders and provides requirements for their invocation. Camarillo Expires May 23, 2004 [Page 1] Internet-Draft Reqs for SIP Exploder Invocation November 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 5. Acknowledges . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Normative References . . . . . . . . . . . . . . . . . . . . . . 4 Informational References . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Intellectual Property and Copyright Statements . . . . . . . . . 6 Camarillo Expires May 23, 2004 [Page 2] Internet-Draft Reqs for SIP Exploder Invocation November 2003 1. Introduction Some applications require that, at a given moment, a SIP UA performs a similar transaction with a number of remote UAs. For example, an instant messaging application that needs to send a particular message (e.g., "Hello folks") to n receivers needs to send n MESSAGE requests; one to each receiver. When the transacton that needs to be repeated consists of a large request and/or the number of recipients is high, the access network of the UA needs to carry a considerable amount of traffic. Completing all the transactions on a low-bandwidth access would require a long time. This is unacceptable for some applications. A solution to this problem consists of introducing exploders in the network. The task of an exploder is to receive a request from a UA and send a number of similar requests to a number of destinations. Once the requests are sent, the exploder needs to inform the UA about their status. Effectively, the exploder behaves as a B2BUA. Note that resource lists, as described in [2], already use SIP exploders for SUBSCRIBE transactions. However, the set of destinations needs to be preconfigured using out-of-band mechanisms (e.g., XCAP). The Advanced Instant Messaging Requirements for SIP [3] also mentions the need for exploders for MESSAGE transactions: "REQ-GROUP-3: It MUST be possible for a user to send to an ad-hoc group, where the identities of the recipients are carried in the message itself." The remainder of this document provides requirements for a potential mechanism that would allow UAs to invoke exploders in an efficient manner. 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. Requirements 1. The invocation mechanism MUST allow the invoker to provide a list of destination URIs to the exploder. This URI list MAY Camarillo Expires May 23, 2004 [Page 3] Internet-Draft Reqs for SIP Exploder Invocation November 2003 consist of one or more URIs. 2. It MUST be possible to send URI list "deltas" to update the list of URIs handled by the exploder. 3. The invocation mechanism MUST NOT be request specific. 4. The invocation mechanism SHOULD NOT require more than one RTT. 5. An exploder MAY provide services beyond request explosion. That is, exploders can be modelled as application servers. For example, an exploder handling INVITE requests may behave as a conference server and perform media mixing for all the participants. 6. The interpretation of the meaning of the URI list sent by the invoker MUST be at the discretion of the application to which the list is sent. 7. It MUST be possible for the invoker to find out about the result of the operations performed by the application with the URI list. An invoker may, for instance, be interested in the status of the transactions initiated by the exploder. 8. It MUST be possible for the application that makes use of a list of URIs to convey the list of URIs to any recipients of messages created by the application from that list. 9. Exploders MUST NOT perform any request explosion without authenticating the invoker. 10. The UA MUST be able to provide credentials to the exploder so that the exploder can use them to prove to the destinations that it is sending requests on behalf of the UA. 4. Security Considerations Requirements related to security are considered in Section 3. 5. Acknowledges Duncan Mills and Miguel A. Garcia-Martin supported the idea of 1 to n MESSAGEs. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Camarillo Expires May 23, 2004 [Page 4] Internet-Draft Reqs for SIP Exploder Invocation November 2003 Levels", BCP 14, RFC 2119, March 1997. Informational References [2] 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. [3] Rosenberg, J., "Advanced Instant Messaging Requirements for the Session Initiation Protocol (SIP)", draft-rosenberg-simple-messaging-requirements-00 (work in progress), December 2002. Author's Address Gonzalo Camarillo Ericsson Hirsalantie 11 Jorvas 02420 Finland EMail: Gonzalo.Camarillo@ericsson.com Camarillo Expires May 23, 2004 [Page 5] Internet-Draft Reqs for SIP Exploder Invocation November 2003 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 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. 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