SIPPING Working Group G. Camarillo Internet-Draft Ericsson Expires: January 6, 2005 July 8, 2004 Connection-Establishment Preconditions in the Session Initiation Protocol (SIP) draft-camarillo-mmusic-connection-precon-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 3668. 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 6, 2005. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document defines the connection-establishment precondition type for the SIP preconditions framework. Connection-establishment preconditions are met when a transport connection (e.g., a TCP connection) is successfully established between two endpoints. Camarillo Expires January 6, 2005 [Page 1] Internet-Draft Connection-Establishment Preconditions July 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Precondition Tag . . . . . . . . . . . . . . . . . . . . . . . 3 4. Status Type . . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Direction Tag . . . . . . . . . . . . . . . . . . . . . . . . 3 6. Precondition Strength . . . . . . . . . . . . . . . . . . . . 4 7. Suspending and Resuming Session Establishment . . . . . . . . 4 8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 9. Security Considerations . . . . . . . . . . . . . . . . . . . 4 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 11.1 Normative References . . . . . . . . . . . . . . . . . . . . 5 11.2 Informational References . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 5 Intellectual Property and Copyright Statements . . . . . . . . 6 Camarillo Expires January 6, 2005 [Page 2] Internet-Draft Connection-Establishment Preconditions July 2004 1. Introduction RFC 3312 [3] defines a framework for preconditions for SIP [2], which is updated by [4]. This document defines a new precondition type for that framework: connection-establishment preconditions. UAs (User Agents) use connection-establishment preconditions when they need to know whether a transport connection (e.g., a TCP connection) has been established successfully and is ready to carry user data. We define the connection-establishment precondition type following the guidelines provided in [4] to extend the SIP preconditions framework. 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. Precondition Tag The precondition tag associated with the connection-establishment preconditions is "conn". This precondition tag is registered with the IANA in Section 10. 4. Status Type RFC 3312 [3] defines two status types, end-to-end and segmented, but only the end-to-end status type applies to connection-establishment preconditions. So, connection-establishment preconditions MUST use the end-to-end status type and MUST NOT use the segmented status type. 5. Direction Tag RFC 3312 [3] defines four direction tags: none, send, recv, and sendrecv. Once a transport connection is established, they indicate in which directions the connection can carry user data. For example, a successfully-established TCP connection would have an associated direction tag of sendrecv because it can carry data in both directions. Camarillo Expires January 6, 2005 [Page 3] Internet-Draft Connection-Establishment Preconditions July 2004 6. Precondition Strength RFC 3312 [3] defines optional and mandatory preconditions, but only mandatory preconditions apply to connection-establishment preconditions. So, connection-establishment preconditions MUST NOT use optional preconditions. 7. Suspending and Resuming Session Establishment According to [4], documents defining new precondition types need to describe the behavior of UAs from the moment session establishment is suspended due to a set of preconditions until is resumed when these preconditions are met. While session establishment is suspended due to connection-establishment preconditions, user agents SHOULD not send any user data over any media stream. Additionally, the UAS (User Agent Server) SHOULD NOT alert the called user. Offers with connection-establishment preconditions in re-INVITEs or UPDATEs follow the rules given in Section 6 of RFC 3312 [3]. Both user agents SHOULD continue using the old session parameters until all the mandatory preconditions are met. At that moment, the user agents can begin using the new session parameters. 8. Examples TBD m=audio 20000 RTP/AVP 0 a=curr:conn e2e none a=des:conn mandatory e2e sendrecv 9. Security Considerations TBD. 10. IANA Considerations TBD. 11. References Camarillo Expires January 6, 2005 [Page 4] Internet-Draft Connection-Establishment Preconditions July 2004 11.1 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] Camarillo, G., Marshall, W. and J. Rosenberg, "Integration of Resource Management and Session Initiation Protocol (SIP)", RFC 3312, October 2002. [4] Camarillo, G., "Interactions of Preconditions with Session Mobility in the Session Initiation Protocol (SIP)", draft-ietf-sip-rfc3312-update-00 (work in progress), November 2003. 11.2 Informational References Author's Address Gonzalo Camarillo Ericsson Hirsalantie 11 Jorvas 02420 Finland EMail: Gonzalo.Camarillo@ericsson.com Camarillo Expires January 6, 2005 [Page 5] Internet-Draft Connection-Establishment Preconditions July 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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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 (2004). 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. Camarillo Expires January 6, 2005 [Page 6]