Miscellaneous Capabilities Negotiation in the Session Description Protocol (SDP)
RFC 7006
Internet Engineering Task Force (IETF) M. Garcia-Martin
Request for Comments: 7006 Ericsson
Category: Standards Track S. Veikkolainen
ISSN: 2070-1721 Nokia
R. Gilman
September 2013
Miscellaneous Capabilities Negotiation in the
Session Description Protocol (SDP)
Abstract
The Session Description Protocol (SDP) has been extended with a
capability negotiation mechanism framework that allows the endpoints
to negotiate transport protocols and attributes. This framework has
been extended with a media capabilities negotiation mechanism that
allows endpoints to negotiate additional media-related capabilities.
This negotiation is embedded into the widely used SDP offer/answer
procedures.
This memo extends the SDP capability negotiation framework to allow
endpoints to negotiate three additional SDP capabilities. In
particular, this memo provides a mechanism to negotiate bandwidth
("b=" line), connection data ("c=" line), and session or media titles
("i=" line for each session or media).
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/rfc7006.
Garcia-Martin, et al. Standards Track [Page 1]
RFC 7006 SDP Misc. Capabilities Negotiation September 2013
Copyright Notice
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Table of Contents
1. Introduction ....................................................3
2. Conventions Used in This Document ...............................3
3. Protocol Description ............................................4
3.1. Extensions to SDP ..........................................4
3.1.1. Bandwidth Capability ................................6
3.1.2. Connection Data Capability ..........................8
3.1.3. Title Capability ...................................12
3.2. Session Level versus Media Level ..........................16
3.3. Offer/Answer Model Extensions .............................17
3.3.1. Generating the Initial Offer .......................17
3.3.2. Generating the Answer ..............................17
3.3.3. Offerer Processing of the Answer ...................18
3.3.4. Modifying the Session ..............................18
4. Field Replacement Rules ........................................18
5. Security Considerations ........................................18
6. IANA Considerations ............................................19
6.1. New SDP Attributes ........................................19
6.2. New Option Tags ...........................................20
6.3. New SDP Capability Negotiation Configuration Parameters ...20
7. Acknowledgments ................................................20
8. References .....................................................20
8.1. Normative References ......................................20
8.2. Informative References ....................................21
Garcia-Martin, et al. Standards Track [Page 2]
RFC 7006 SDP Misc. Capabilities Negotiation September 2013
1. Introduction
The Session Description Protocol (SDP) [RFC4566] is intended for
describing multimedia sessions for the purposes of session
announcement, session invitation, and other forms of multimedia
session initiation. SDP has been extended with an SDP Capability
Negotiation Mechanism Framework [RFC5939] that allows the endpoints
to negotiate capabilities, such as support for the Real-time
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