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An Offer/Answer Model with Session Description Protocol (SDP) (RFC3264)

IP.com Disclosure Number: IPCOM000009209D
Original Publication Date: 2002-Jun-01
Included in the Prior Art Database: 2002-Aug-13
Document File: 26 page(s) / 61K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Rosenberg: AUTHOR [+2]

Abstract

This document defines a mechanism by which two entities can make use of the Session Description Protocol (SDP) to arrive at a common view of a multimedia session between them. In the model, one participant offers the other a description of the desired session from their perspective, and the other participant answers with the desired session from their perspective. This offer/answer model is most useful in unicast sessions where information from both participants is needed for the complete view of the session. The offer/answer model is used by protocols like the Session Initiation Protocol (SIP).

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Network Working Group                                       J. Rosenberg

Request for Comments: 3264                                   dynamicsoft

Obsoletes: 2543                                           H. Schulzrinne

Category: Standards Track                                    Columbia U.

                                                               June 2002

   An Offer/Answer Model with 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.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document defines a mechanism by which two entities can make use

   of the Session Description Protocol (SDP) to arrive at a common view

   of a multimedia session between them.  In the model, one participant

   offers the other a description of the desired session from their

   perspective, and the other participant answers with the desired

   session from their perspective.  This offer/answer model is most

   useful in unicast sessions where information from both participants

   is needed for the complete view of the session.  The offer/answer

   model is used by protocols like the Session Initiation Protocol

   (SIP).

Table of Contents

   1          Introduction ........................................    2

   2          Terminology .........................................    3

   3          Definitions .........................................    3

   4          Protocol Operation ..................................    4

   5          Generating the Initial Offer ........................    5

   5.1        Unicast Streams .....................................    5

   5.2        Multicast Streams ...................................    8

   6          Generating the Answer ...............................    9

   6.1        Unicast Streams .....................................    9

   6.2        Multicast Streams ...................................   12

   7          Offerer Processing of the Answer ....................   12

   8          Modifying the Session ...............................   13

Rosenberg & Schulzrinne     Standards Track                     [Page 1]

RFC 3264  An Offer/Answer Model Session Description Protocol   June 2002

   8.1        Adding a Media Stream ............