The 3G IP Multimedia Subsystem (IMS) Merging the Internet and the Cellular Worlds
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The 3G IP Multimedia Subsystem (IMS) Merging the Internet and the Cellular Worlds Second Edition Gonfalon Camarilla Ericsson, Finland Miguel A. Garcia-Martin Nokia Research Center, Finland John Wiley & Sons, Ltd Copyright © 2006 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone (+44) 1243 779777 Email (for orders and customer service enquiries): [email protected] Visit our Home Page on www.wiley.com Reprinted with corrections May 2006 All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London WIT 4LP, UK, without the permission in writing of the Publisher. 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Other Wiley Editorial Offices John Wiley & Sons Inc., 111 River Street, Hoboken, NJ 07030, USA Jossey-Bass, 989 Market Street, San Francisco, CA 94103-1741, USA Wiley-VCH Verlag GmbH, Boschstr. 12, D-69469 Weinheim, Germany John Wiley & Sons Australia Ltd, 42 McDougall Street, Milton, Queensland 4064, Australia John Wiley & Sons (Asia) Pte Ltd, 2 Clementi Loop #02-01, Jin Xing Distripark, Singapore 129809 John Wiley & Sons Canada Ltd, 22 Worcester Road, Etobicoke, Ontario, Canada M9W 1L1 Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Library of Congress Cataloging-in-Publication Data Camarillo, Gonzalo. The 3G IP multimedia subsystem (IMS) : merging the Internet and the cellular worlds / Gonzalo Camarillo, Miguel A. Garcia-Martin.-2nd ed. p. cm. Includes bibliographical references and index. ISBN-13: 978-0-470-01818-7 (cloth : alk. paper) ISBN-10: 0-470-01818-6 (cloth : alk. paper) 1. Wireless communication systems. 2. Mobile communication systems. 3. Multimedia communications. I. Garcia-Martin, Miguel A. II. Title. TK5103.2.C35 2OO6 621-384^C22 2005026863 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN-13 978-0-470-01818-7 (HB) ISBN-10 0-470-01818-6 (HB) Typeset by Sunrise Setting Ltd, Torquay, Devon, UK. Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire. This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least two trees are planted for each one used for paper production. To my parents, Anselmo and Isabel; my brothers, Alvaro, Daniel, and Ignacio; and Viviana. They all are a source of energy and motivation in everything I do. Gonzalo To my daughter Maria Elizabeth, who was born at the time I started writing this book, she is the sunshine of my life; my wife Jelena, who provided me with all the support and love I needed; my parents, Jose and Mari-Luz, my aunt Feli, my brother Javier Jose who, through the distance, encouraged and supported me during this project. Miguel Angel Contents Foreword by Stephen Hayes xvii Foreword by Allison Mankin and Jon Peterson xix About the Authors xxi Preface to the Second Edition xxiii Preface to the First Edition xxv Acknowledgements xxvii Part I Introduction to the IMS 1 1 IMS Vision: Where Do We Want to Go? 5 1.1 The Internet 5 1.2 The Cellular World 6 1.3 Why do we need the IMS? 6 1.4 Relation between IMS and non-IMS Services 8 2 The History of the IMS Standardization 9 2.1 Relations between IMS-related Standardization Bodies 9 2.2 Internet Engineering Task Force 10 2.2.1 Structure of the IETF 10 2.2.2 Working Group Operations 11 2.2.3 Types of RFCs 12 2.3 Third Generation Partnership Project 13 2.3.1 3GPP Structure 14 2.3.2 3GPP Deliverables 15 2.4 Third Generation Partnership Project 2 16 2.4.1 3GPP2 Structure 16 2.4.2 3GPP2 Deliverables 16 2.5 IETF-3GPP/3GPP2 Collaboration 17 2.5.1 Internet Area 18 2.5.2 Operations and Management Area 18 2.5.3 Transport Area 19 viii CONTENTS 2.6 Open Mobile Alliance 19 2.6.1 OMA Releases and Specifications 20 2.6.2 Relationship between OMA and 3GPP/3GPP2 21 2.6.3 Relationship between OMA and the IETF 22 3 General Principles of the IMS Architecture 23 3.1 From Circuit-switched to Packet-switched 23 3.1.1 GSM Circuit-switched 23 3.1.2 GSM Packet-switched 24 3.2 IMS Requirements 24 3.2.1 IP Multimedia Sessions 25 3.2.2 QoS 25 3.2.3 Interworking 26 3.2.4 Roaming 26 3.2.5 Service Control 26 3.2.6 Rapid Service Creation 27 3.2.7 Multiple Access 27 3.3 Overview of Protocols used in the IMS 27 3.3.1 Session Control Protocol 27 3.3.2 The AAA Protocol 28 3.3.3 Other Protocols 29 3.4 Overview of IMS Architecture 29 3.4.1 The Databases: the HSS and the SLF 30 3.4.2 TheCSCF 31 3.4.3 The AS 33 3.4.4 TheMRF 35 3.4.5 TheBGCF 35 3.4.6 The IMS-ALG and the TrGW 35 3.4.7 The PSTN/CS Gateway 36 3.4.8 Home and Visited Networks 38 3.5 Identification in the IMS 39 3.5.1 Public User Identities 40 3.5.2 Private User Identities 40 3.5.3 The Relation between Public and Private User Identities 41 3.5.4 Public Service Identities 42 3.6 SIM, USIM, and ISIM in 3GPP 42 3.6.1 SIM 43 3.6.2 USIM 43 3.6.3 ISIM 45 Part II The Signaling Plane in the IMS 47 4 Session Control on the Internet 51 4.1 SIP Functionality 51 4.1.1 Session Descriptions and SDP 51 4.1.2 The Offer/Answer Model 52 4.1.3 SIP and SIPS URIs 53 4.1.4 User Location 54 CONTENTS ix 4.2 SIP Entities 55 4.2.1 Forking Proxies 57 4.2.2 Redirect Servers 58 4.3 Message Format 59 4.4 The Start Line in SIP Responses: the Status Line 59 4.5 The Start Line in SIP Requests: the Request Line 60 4.6 HeaderFields 60 4.7 Message Body 62 4.8 SIP Transactions 63 4.9 Message Flow for Session Establishment 64 4.10 SIP Dialogs 67 4.10.1 Record-Route, Route, and Contact HeaderFields 70 4.11 Extending SIP 70 4.11.1 New Methods 72 4.12 Caller Preferences and User Agent Capabilities 72 4.13 Reliability of Provisional Responses 73 4.14 Preconditions 76 4.15 Event Notification 77 4.15.1 High Notification Rates 79 4.16 Signaling Compression 80 4.16.1 SigComp Extended Operations 81 4.16.2 Static SIP/SDP Dictionary 82 4.17 Content Indirection 82 4.18 The REFER Method 85 5 Session Control in the IMS 87 5.1 Prerequisites for Operation in the IMS 88 5.2 IPv4 and IPv6 in the IMS 89 5.3 IP Connectivity Access Network 90 5.4 P-CSCF Discovery 91 5.5 IMS-level Registration 93 5.5.1 IMS Registration with an ISIM 93 5.5.2 IMS Registration with a USIM 101 5.6 Subscription to the reg Event State 106 5.7 Basic Session Setup 109 5.7.1 The IMS Terminal Sends an INVITE Request 113 5.7.2 The Originating P-CSCF Processes the INVITE Request 120 5.7.3 The Originating S-CSCF Processes the INVITE Request 121 5.7.4 The Terminating I-CSCF Processes the INVITE Request 125 5.7.5 The Terminating S-CSCF Processes the INVITE Request 126 5.7.6 The Terminating P-CSCF Processes the INVITE Request 129 5.7.7 The Callee's Terminal Processes the INVITE Request 129 5.7.8 Processing the 183 Response 133 5.7.9 The Caller's IMS Terminal Processes the 183 Response 133 5.7.10 The Callee's IMS Terminal Processes the PRACK request 134 5.7.11 Alerting the Callee 137 x CONTENTS 5.8 Application Servers: Providing Services to Users 142 5.8.1 Generalities about Application Servers 142 5.8.2 Types of Application Servers 143 5.8.3 The Session Setup Model through Application Servers 147 5.8.4 Filter Criteria 155 5.8.5 An Example of Service Execution 159 5.9 Interworking 162 5.9.1 SIP-PSTN Interworking 162 5.9.2 Interworking with Non-IMS SIP-based Networks 165 5.10 Emergency Sessions 169 6 AAA on the Internet 171 6.1 Authentication, Authorization, and Accounting 171 6.2 AAA Framework on the Internet 171 6.3 The Diameter Protocol 173 6.3.1 Diameter Sessions 174 6.3.2 The Format of a Diameter Message 175 6.3.3 Attribute Value Pairs 176 6.3.4 The AAA and AAAS URIs 177 6.3.5 Diameter Base Protocol Commands 178 6.3.6 Diameter Base Protocol AVPs 180 7 AAA in the IMS 183 7.1 Authentication and Authorization in the IMS 183 7.2 The Cx and Dx Interfaces 183 7.2.1 Command Codes Defined in the Diameter Application for the Cx Interface 185 7.2.2 AVPs Defined in the Diameter Application for the Cx Interface .