The Session Description Protocol (SDP) Grouping Framework
RFC 5888
Document | Type |
RFC - Proposed Standard
(June 2010; Errata)
Updated by RFC 8843
Obsoletes RFC 3388
|
|
---|---|---|---|
Authors | Henning Schulzrinne , Gonzalo Camarillo | ||
Last updated | 2020-01-21 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5888 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Cullen Jennings | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) G. Camarillo Request for Comments: 5888 Ericsson Obsoletes: 3388 H. Schulzrinne Category: Standards Track Columbia University ISSN: 2070-1721 June 2010 The Session Description Protocol (SDP) Grouping Framework Abstract In this specification, we define a framework to group "m" lines in the Session Description Protocol (SDP) for different purposes. This framework uses the "group" and "mid" SDP attributes, both of which are defined in this specification. Additionally, we specify how to use the framework for two different purposes: for lip synchronization and for receiving a media flow consisting of several media streams on different transport addresses. This document obsoletes RFC 3388. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc5888. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Camarillo & Schulzrinne Standards Track [Page 1] RFC 5888 SDP Grouping Framework June 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Overview of Operation . . . . . . . . . . . . . . . . . . . . 3 4. Media Stream Identification Attribute . . . . . . . . . . . . 4 5. Group Attribute . . . . . . . . . . . . . . . . . . . . . . . 4 6. Use of "group" and "mid" . . . . . . . . . . . . . . . . . . . 4 7. Lip Synchronization (LS) . . . . . . . . . . . . . . . . . . . 5 7.1. Example of LS . . . . . . . . . . . . . . . . . . . . . . 5 8. Flow Identification (FID) . . . . . . . . . . . . . . . . . . 6 8.1. SIP and Cellular Access . . . . . . . . . . . . . . . . . 6 8.2. DTMF Tones . . . . . . . . . . . . . . . . . . . . . . . . 7 8.3. Media Flow Definition . . . . . . . . . . . . . . . . . . 7 8.4. FID Semantics . . . . . . . . . . . . . . . . . . . . . . 7 8.4.1. Examples of FID . . . . . . . . . . . . . . . . . . . 8 8.5. Scenarios That FID Does Not Cover . . . . . . . . . . . . 11 8.5.1. Parallel Encoding Using Different Codecs . . . . . . . 11 8.5.2. Layered Encoding . . . . . . . . . . . . . . . . . . . 12 8.5.3. Same IP Address and Port Number . . . . . . . . . . . 12 9. Usage of the "group" Attribute in SIP . . . . . . . . . . . . 13 9.1. Mid Value in Answers . . . . . . . . . . . . . . . . . . . 13 9.1.1. Example . . . . . . . . . . . . . . . . . . . . . . . 14 9.2. Group Value in Answers . . . . . . . . . . . . . . . . . . 15 9.2.1. Example . . . . . . . . . . . . . . . . . . . . . . . 15 9.3. Capability Negotiation . . . . . . . . . . . . . . . . . . 16 9.3.1. Example . . . . . . . . . . . . . . . . . . . . . . . 16 9.4. Backward Compatibility . . . . . . . . . . . . . . . . . . 17 9.4.1. Offerer Does Not Support "group" . . . . . . . . . . . 17 9.4.2. Answerer Does Not Support "group" . . . . . . . . . . 17 10. Changes from RFC 3388 . . . . . . . . . . . . . . . . . . . . 18 11. Security Considerations . . . . . . . . . . . . . . . . . . . 18 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20 14.1. Normative References . . . . . . . . . . . . . . . . . . . 20 14.2. Informative References . . . . . . . . . . . . . . . . . . 20 Camarillo & Schulzrinne Standards Track [Page 2]Show full document text