Session Description Protocol (SDP) Extension For Setting Up Audio and Video Media Streams Over Circuit-Switched Bearers In The Public Switched Telephone Network (PSTN)
draft-ietf-mmusic-sdp-cs-14
MMUSIC WG M. Garcia-Martin
Internet-Draft Ericsson
Intended status: Standards Track S. Veikkolainen
Expires: May 30, 2013 Nokia
November 26, 2012
Session Description Protocol (SDP) Extension For Setting Up Audio and
Video Media Streams Over Circuit-Switched Bearers In The Public Switched
Telephone Network (PSTN)
draft-ietf-mmusic-sdp-cs-14
Abstract
This memo describes use cases, requirements, and protocol extensions
for using the Session Description Protocol (SDP) Offer/Answer model
for establishing audio and video media streams over circuit-switched
bearers in the Public Switched Telephone Network (PSTN).
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 30, 2013.
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Internet-Draft PSTN Circuit-Switched Bearers in SDP November 2012
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Conventions Used in This Document . . . . . . . . . . . . . . 6
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Overview of Operation . . . . . . . . . . . . . . . . . . . . 7
4.1. Example Call Flow . . . . . . . . . . . . . . . . . . . . 7
5. Protocol Description . . . . . . . . . . . . . . . . . . . . . 9
5.1. Level of Compliance . . . . . . . . . . . . . . . . . . . 9
5.2. Extensions to SDP . . . . . . . . . . . . . . . . . . . . 9
5.2.1. Connection Data . . . . . . . . . . . . . . . . . . . 9
5.2.2. Media Descriptions . . . . . . . . . . . . . . . . . . 11
5.2.3. Correlating the PSTN Circuit-Switched Bearer with
SDP . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2.3.1. The "cs-correlation" attribute . . . . . . . . . . 13
5.2.3.2. Caller-ID Correlation Mechanism . . . . . . . . . 13
5.2.3.3. User-User Information Element Correlation
Mechanism . . . . . . . . . . . . . . . . . . . . 14
5.2.3.4. DTMF Correlation Mechanism . . . . . . . . . . . . 16
5.2.3.5. Extensions to correlation mechanisms . . . . . . . 17
5.3. Negotiating the correlation mechanisms . . . . . . . . . . 17
5.3.1. Determining the Direction of the Circuit-Switched
Bearer Setup . . . . . . . . . . . . . . . . . . . . . 18
5.3.2. Populating the cs-correlation attribute . . . . . . . 18
5.3.3. Considerations on successful correlation . . . . . . . 19
5.4. Considerations for Usage of Existing SDP . . . . . . . . . 20
5.4.1. Originator of the Session . . . . . . . . . . . . . . 20
5.4.2. Contact information . . . . . . . . . . . . . . . . . 20
5.5. Considerations for Usage of Third Party Call Control
(3PCC) . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.6. Offer/Answer mode extensions . . . . . . . . . . . . . . . 21
5.6.1. Generating the Initial Offer . . . . . . . . . . . . . 21
5.6.2. Generating the Answer . . . . . . . . . . . . . . . . 23
5.6.3. Offerer processing the Answer . . . . . . . . . . . . 26
5.6.4. Modifying the session . . . . . . . . . . . . . . . . 27
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