Table Of ContentHandbook of SDP for
Multimedia Session Negotiations
Handbook of SDP for
Multimedia Session Negotiations
SIP and WebRTC IP Telephony
Radhika Ranjan Roy
CRC Press
Taylor & Francis Group
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Library of Congress Cataloging‑in‑Publication Data
Names: Roy, Radhika Ranjan, author.
Title: Handbook of SDP for multimedia session negotiations : SIP and
WebRTC IP telephony / Radhika Ranjan Roy.
Description: First edition. | Boca Raton, FL : CRC Press/Taylor & Francis
Group, 2018. | “A CRC title, part of the Taylor & Francis imprint, a member
of the Taylor & Francis Group, the academic division of T&F Informa plc.” | Includes
bibliographical references and index.
Identifiers: LCCN 2017057107 | ISBN 9781138484498 (hardback : acid-free paper)
Subjects: LCSH: Session Description Protocol (Computer network
protocol) | Multimedia communications. | Internet telephony.
Classification: LCC TK5105.15 .R69 2018 | DDC 621.382/12--dc23
LC record available at https://lccn.loc.gov/2017057107
Visit the Taylor & Francis Web site at
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To our dearest son, Debasri Roy, Medicinae Doctoris (M.D.) (January 20, 1988—
October 31, 2014) who had brilliant carrier (Summa Cum Laude—undergraduate),
had so much more to contribute to this country and the world as a whole in the
future, had been so eager for seeing these books get published saying, “Daddy,
you are my hero.” May God let his soul live in peace in His abode.
To my GrandMa for her causeless love, my parents Rakesh Chandra Roy and
Sneholota Roy whose spiritual inspiration remains vividly alive within all of us, my late
sisters GitaSree Roy, Anjali Roy, and Aparna Roy and their spouses and my brother
Raghunath Roy and his wife Nupur for their inspiration, our daughter Elora and our
son-in-law Nick, our son Ajanta, and finally my beloved wife Jharna for their love.
Our special thanks to our son-in-law Nick and our daughter Elora for
their hard works and remain engaged with their creative activities how
to become financially independent standing on their own feet.
It is also inspiring to see how our son Ajanta who himself is an
energetic electrical engineer progressing toward a bright future on
his own right keeping his colleagues and all of us amazed.
Contents
List of Figures ............................................................................................................................xi
List of Tables ............................................................................................................................xv
Preface ....................................................................................................................................xvii
Author ......................................................................................................................................xxi
1 Networked Multimedia Protocols ................................................................................1
1.1 Introduction ............................................................................................................1
1.2 Session Initiation Protocol .......................................................................................2
1.3 WebRTC Protocol ..................................................................................................13
1.4 Summary ................................................................................................................33
1.5 Problems .................................................................................................................33
References ........................................................................................................................34
2 Basic Session Description Protocol ............................................................................35
2.1 Introduction ...........................................................................................................35
2.2 Terminologies and Their Definitions .....................................................................36
2.3 SDP Usage .............................................................................................................43
2.4 Requirements and Recommendations .....................................................................45
2.5 SDP Specification ...................................................................................................47
2.6 SDP Attributes .......................................................................................................59
2.7 Security Considerations .........................................................................................64
2.8 IANA Considerations ............................................................................................64
2.9 Augmented Backus-Naur Form for the SDP .........................................................64
2.10 Changes in RFC 4566 by RFC 4566bis ...............................................................103
2.11 Summary ..............................................................................................................109
2.12 Problems ...............................................................................................................110
References .......................................................................................................................111
3 Negotiations Model in SDP ......................................................................................113
3.1 Offer/Answer Model with SDP ............................................................................113
3.2 ICE for Network Address Translator Traversal by SDP Offer/Answer Protocols ......127
3.3 Summary ..............................................................................................................191
3.4 Problems ...............................................................................................................191
Reference ........................................................................................................................193
4 Capability Declaration in SDP ................................................................................195
4.1 Simple Capability Declaration ..............................................................................195
vii
viii ◾ Contents
4.2 Summary ..............................................................................................................199
4.3 Problems ..............................................................................................................200
5 Media-Level Attribute Support in SDP ....................................................................201
5.1 SDP Label Attribute .............................................................................................201
5.2 SDP Content Attribute ........................................................................................204
5.3 Source-Specific Media Attributes in SDP ............................................................208
5.4 Summary ..............................................................................................................215
5.5 Problems ...............................................................................................................215
6 Semantics for Signaling Media Decoding Dependency in SDP ...............................217
6.1 Decoding Dependency with Layered or Multiple Descriptive Media ...................217
6.2 Summary .............................................................................................................225
6.3 Problems ..............................................................................................................225
Reference .......................................................................................................................226
7 Media Grouping Support in SDP .............................................................................227
7.1 SDP Grouping Framework ..................................................................................228
7.2 Negotiating Media Multiplexing/Bundling Using SDP.......................................239
7.3 RTP Media Streams Grouping in SDP .................................................................261
7.4 Summary .............................................................................................................266
7.5 Problems ..............................................................................................................266
References .......................................................................................................................267
8 Generic Capability Attribute Negotiations in SDP ..................................................269
8.1 SDP Capability Negotiation ................................................................................269
8.2 Negotiation of Generic Image Attributes in SDP..................................................313
8.3 SDP Media Capabilities Negotiation ...................................................................326
8.4 Miscellaneous Capabilities Negotiation in SDP ...................................................357
8.5 Summary .............................................................................................................368
8.6 Problems ..............................................................................................................369
Reference .......................................................................................................................369
9 Network Protocol Support in SDP ...........................................................................371
9.1 Support for IPv4 and IPv6 in SDP .......................................................................372
9.2 SDP Alternate Connectivity (ALTC) Attribute ....................................................373
9.3 Source Address Filters in SDP .............................................................................386
9.4 SDP for Asynchronous Transfer Mode (ATM) Bearer Connections .....................392
9.5 Audio and Video Media Streams over Public Switched Telephone Network
(PSTN) in SDP ...................................................................................................466
9.6 Summary .............................................................................................................487
9.7 Problems ..............................................................................................................488
References ......................................................................................................................489
10 Transport Protocol Support in SDP .........................................................................491
10.1 TCP-Based Media Transport in SDP ...................................................................491
10.2 Summary ..............................................................................................................498
10.3 Problems ..............................................................................................................498
Contents ◾ ix
11 RTP Media Loopback Support in SDP ....................................................................499
11.1 Support for Media Loopback in SDP and RTP ...................................................499
11.2 Summary ..............................................................................................................513
11.3 Problems ...............................................................................................................513
12 Quality-of-Service Support in SDP ..........................................................................515
12.1 QOS Mechanism Selection SDP ..........................................................................516
12.2 SDP Bandwidth Modifiers for RTCP Bandwidth .................................................518
12.3 RTCP Attribute in SDP .......................................................................................522
12.4 Transport Independent Bandwidth Modifier for SDP ..........................................525
12.5 Connectivity Preconditions for SDP Media Streams ............................................536
12.6 Summary .............................................................................................................544
12.7 Problems ...............................................................................................................545
13 Application-Specific Extensions in SDP ...................................................................547
13.1 SDP Offer/Answer Mechanism to Enable File Transfer .......................................547
13.2 SDP Format for Binary Floor Control Protocol (BFCP) Streams..........................573
13.3 Summary .............................................................................................................577
13.4 Problems ...............................................................................................................578
14 Service-Specific Extension in SDP ...........................................................................579
14.1 SDP and RTSP Extensions for 3GPP Packet-Switched Services ...........................579
14.2 SDP Attributes for OMA Services .......................................................................586
14.3 SDP and SIP Extensions for PSTN/Internet Interworking Services ....................587
14.4 Summary ..............................................................................................................629
14.5 Problems ...............................................................................................................629
References ......................................................................................................................630
15 Compression Support in SDP...................................................................................631
15.1 SDP and SIP Static Dictionary for Signaling Compression ..................................631
15.2 Summary .............................................................................................................648
15.3 Problems ..............................................................................................................648
16 Security Capability Negotiation in SDP ..................................................................651
16.1 Key Management Extensions for SDP and RTSP .................................................652
16.2 SDP Security Descriptions for Media Streams .....................................................667
16.3 Connection-Oriented Media Transport over TLS Protocol in SDP .....................689
16.4 Security Preconditions for SDP Media Streams ...................................................694
16.5 Media Description for IKE in SDP ......................................................................702
16.6 Summary ..............................................................................................................713
16.7 Problems ...............................................................................................................715
References .......................................................................................................................717
17 Security Considerations in Using SDP Attributes ....................................................719
17.1 Basic SDP Messages.............................................................................................720
17.2 Negotiations Model in SDP ..................................................................................721
17.3 Capability Declaration in SDP ............................................................................726
17.4 Media-Level Attribute Support ............................................................................727
