Source-Specific Media Attributes in the Session Description Protocol (SDP)
RFC 5576
| Document | Type | RFC - Proposed Standard (June 2009; No errata) | |
|---|---|---|---|
| Authors | Jonathan Lennox , Joerg Ott , Thomas Schierl | ||
| Last updated | 2015-10-14 | ||
| Replaces | draft-lennox-mmusic-sdp-source-attributes | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Stream | WG state | WG Document | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5576 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Cullen Jennings | ||
| Send notices to | (None) | ||
Network Working Group J. Lennox
Request for Comments: 5576 Vidyo
Category: Standards Track J. Ott
Helsinki University of Technology
T. Schierl
Fraunhofer HHI
June 2009
Source-Specific Media Attributes in the
Session Description Protocol (SDP)
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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Lennox, et al. Standards Track [Page 1]
RFC 5576 Source-Specific SDP Attributes June 2009
Abstract
The Session Description Protocol (SDP) provides mechanisms to
describe attributes of multimedia sessions and of individual media
streams (e.g., Real-time Transport Protocol (RTP) sessions) within a
multimedia session, but does not provide any mechanism to describe
individual media sources within a media stream. This document
defines a mechanism to describe RTP media sources, which are
identified by their synchronization source (SSRC) identifiers, in
SDP, to associate attributes with these sources, and to express
relationships among sources. It also defines several source-level
attributes that can be used to describe properties of media sources.
Table of Contents
1. Introduction ....................................................2
2. Terminology .....................................................3
3. Overview ........................................................3
4. Media Attributes ................................................4
4.1. The "ssrc" Media Attribute .................................5
4.2. The "ssrc-group" Media Attribute ...........................6
5. Usage of Identified Source Identifiers in RTP ...................7
6. Source Attributes ...............................................8
6.1. The "cname" Source Attribute ...............................8
6.2. The "previous-ssrc" Source Attribute .......................9
6.3. The "fmtp" Source Attribute ................................9
6.4. Other Source Attributes ...................................10
7. Examples .......................................................10
8. Usage With the Offer/Answer Model ..............................11
9. Backward Compatibility .........................................11
10. Formal Grammar ................................................12
11. Security Considerations .......................................13
12. IANA Considerations ...........................................14
12.1. New SDP Media-Level Attributes ...........................14
12.2. Registry for Source-Level Attributes .....................14
12.3. Registry for Source Grouping Semantics ...................15
13. References ....................................................16
13.1. Normative References .....................................16
13.2. Informative References ...................................16
1. Introduction
The Session Description Protocol (SDP) [RFC4566] provides mechanisms
to describe attributes of multimedia sessions and of media streams
(e.g., Real-time Transport Protocol (RTP) [RFC3550] sessions) within
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