Network Working Group J. Hildebrand Internet-Draft Jabber, Inc. Expires: August 22, 2003 February 21, 2003 TINS: A Transport for Initiating and Negotiating Sessions using SDPng over XMPP draft-hildebrand-xmpp-sdpng-00 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 August 22, 2003. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document describes a method of initiating and negotiating media sessions by using SDPng on top of the eXtensible Messaging and Presence Protocol (XMPP) as the signalling protocol. Hildebrand Expires August 22, 2003 [Page 1] Internet-Draft TINS February 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Discussion Venue . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Intellectual Property Notice . . . . . . . . . . . . . . . . . 3 2. Stanza Flow Overview . . . . . . . . . . . . . . . . . . . . . 4 3. Transactions . . . . . . . . . . . . . . . . . . . . . . . . . 8 4. TINS Methods . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.1 INVITE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 ACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3 BYE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 13 Full Copyright Statement . . . . . . . . . . . . . . . . . . . 14 Hildebrand Expires August 22, 2003 [Page 2] Internet-Draft TINS February 2003 1. Introduction The MMUSIC WG has defined an XML format for Session Description and Capability Negotiation (SDPng [1]). Given the availability of a native XML transport in the form of the Extensible Messaging and Presence Protocol (XMPP [2]), it may be valuable to explore how to build a framework for media stream/session initiation and negotiation over XMPP. This document explores such a framework, with SDPng over XMPP providing a semantics for signalling call setup that is similar to the semantics alternatively provided by the Session Initiation Protocol (SIP [3]). 1.1 Terminology This document inherits terminology defined in SDPng [1] and in XMPP Core [2]. The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [4]. 1.2 Discussion Venue The author welcomes discussion and comments related to the topics presented in this document. The preferred forum is the mailing list, for which archives and subscription information are available at . 1.3 Intellectual Property Notice This document is in full compliance with all provisions of Section 10 of RFC 2026. Hildebrand Expires August 22, 2003 [Page 3] Internet-Draft TINS February 2003 2. Stanza Flow Overview The following is an example flow of XMPP stanzas to initiate a call. The from addresses will usually be added by the XMPP server, but are shown for clarity. Step 1: A sends an invite to B: 1234@hostA.example.com This message contains a TINS invite, but your client does not support TINS. Telephony media stream Hildebrand Expires August 22, 2003 [Page 4] Internet-Draft TINS February 2003 Step 2: B tells A that it is trying: 1234@hostA.example.com Step 3: B tells A that it is ringing: 1234@hostA.example.com Hildebrand Expires August 22, 2003 [Page 5] Internet-Draft TINS February 2003 Step 4: B sends A updated description: 1234@hostA.example.com Step 5: A sends an ACKnowldgement: 1234@hostA.example.com Hildebrand Expires August 22, 2003 [Page 6] Internet-Draft TINS February 2003 Step 6: B hangs up: 1234@hostA.example.com Step 7: A acknowledges the hang up: 1234@hostA.example.com Hildebrand Expires August 22, 2003 [Page 7] Internet-Draft TINS February 2003 3. Transactions The element from XMPP is used to group TINS messages together into a shared context. A unique thread value MUST be used for each transaction. An example of a transaction might be a single voice call. Hildebrand Expires August 22, 2003 [Page 8] Internet-Draft TINS February 2003 4. TINS Methods The following methods can be used in a TINS message. 4.1 INVITE Invite the target user to an out-of-band session. The content inside the element MAY be SDPng descriptions of the connection types offered. If a session is already established for this transaction, the new INVITE serves as a renegotiation of session parameters. 4.2 ACK The initiator tells the invitee that an out-of-band session has been established. 4.3 BYE Either side of the conversation decides to terminate the transaction. This message SHOULD cause all resources associated with this transaction to be freed, and any associated network connections to be terminated. Hildebrand Expires August 22, 2003 [Page 9] Internet-Draft TINS February 2003 5. Results In reply to each of the method messages, the receiver sends 0 or more replies, with the method set to 'result'. Result codes are as specified in RFC 3261, section 21. Hildebrand Expires August 22, 2003 [Page 10] Internet-Draft TINS February 2003 6. Security Considerations TINS is subject to the same security considerations as XMPP, particularly with regard to authentication and channel encryption. This document does not describe how the media protocols (e.g. RTP) traverse firewalls and NATs. There is no general-purpose way to ensure that media protocol connections are associated with the in-band TINS conversation. Hildebrand Expires August 22, 2003 [Page 11] Internet-Draft TINS February 2003 7. IANA Considerations None Hildebrand Expires August 22, 2003 [Page 12] Internet-Draft TINS February 2003 References [1] Ott, J., Bormann, C. and D. Kutscher, "Session Description and Capability Negotiation", draft-ietf-mmusic-sdpng-05 (work in progress), July 2002. [2] Saint-Andre, P. and J. Miller, "XMPP Core (draft-ietf-xmpp-core- 03, work in progress)", February 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. [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [5] Internet Assigned Numbers Authority, "Internet Assigned Numbers Authority", January 1998, . Author's Address Joe Hildebrand Jabber, Inc. EMail: jhildebrand@jabber.com URI: http://www.jabber.com/ Hildebrand Expires August 22, 2003 [Page 13] Internet-Draft TINS February 2003 Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Hildebrand Expires August 22, 2003 [Page 14]