THE IMS IP MULTIMEDIA CONCEPTS AND SERVICES, THIRD EDITION

Transcription

1 THE IMS IP MULTIMEDIA CONCEPTS AND SERVICES, THIRD EDITION Miikka Poikselkä Nokia Siemens Networks, Finland Georg Mayer Nokia, Finland A John Wiley and Sons, Ltd., Publication

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3 THE IMS

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5 THE IMS IP MULTIMEDIA CONCEPTS AND SERVICES, THIRD EDITION Miikka Poikselkä Nokia Siemens Networks, Finland Georg Mayer Nokia, Finland A John Wiley and Sons, Ltd., Publication

6 This edition first published John Wiley & Sons Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 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 or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Poikselka, Miikka. The IMS : IP multimedia concepts and services / Miikka Poikselka, Georg Mayer. 3rd ed. p. cm. Rev. ed. of: IMS / Miikka Poikselka... [et al.] Includes bibliographical references and index. ISBN (cloth) 1. Multimedia communications. 2. Wireless communication systems. 3. Mobile communication systems. I. Mayer, Georg, II. IMS. III. Title. TK P dc British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN Typeset in 10/12 Times by Laserwords Private Limited, Chennai, India Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire

7 Contents Foreword Preface Acknowledgements List of Figures List of Tables xv xvii xix xxi xxvii PART I IMS ARCHITECTURE AND CONCEPTS 1 Introduction What is the Internet Protocol Multimedia Subsystem (IMS)? Fixed and Mobile Convergence Example of IMS Services Where did it come from? GPP Release 99 (3GPP R99) GPP Release GPP Releases 5 and IMS Development in other Standardization Development Organizations GPP Release 7 and common IMS Insight to 3GPP Release Why a SIP Solution Based on 3GPP Standards? 13 2 IP Multimedia Subsystem Architecture Architectural Requirements IP Multimedia Sessions IP Connectivity Ensuring Quality of Service for IP Multimedia Services IP Policy Control for Ensuring Correct Usage of Media Resources Secure Communication Charging Arrangements Support of Roaming 19

8 vi Contents Interworking with Other Networks Service Control Model Layered Design and Access Independence Description of IMS-related Entities and Functionalities Call Session Control Functions (CSCF) Emergency Call Session Control Function (E-CSCF) Databases Service Functions IMS-CS Interworking Functions Support Functions Charging Entities GPRS Entities IMS Reference Points Gm Reference Point Mw Reference Point IMS Service Control (ISC) Reference Point Ma Reference Point Cx Reference Point Dx Reference Point Sh Reference Point Dh Reference Point Si Reference Point Mi Reference Point Mj Reference Point Mk Reference Point Mg Reference Point Mm Reference Point Mr Reference Point Mp Reference Point Mn Reference Point Gx Reference Point Rx Reference Point Charging Reference Points Mx, Ix and Iq Reference Point Ml Reference Point Ut Reference Point 46 3 IMS Concepts Overview Registration Mechanism to Register Multiple User Identities at a Go Session Initiation Identification Public User Identity Private User Identity Relationship between Private and Public User Identities Identity Generation Without ISIM Identification of Services (Public Service Identities) 55

9 Contents vii Identification of User s Device Identification of Network Entities IP Multimedia Services Identity Module (ISIM) Sharing a Single User Identity between Multiple Devices Discovering the IMS Entry Point S-CSCF Assignment S-CSCF Assignment during Registration S-CSCF Assignment to Execute Services for an Unregistered User S-CSCF Assignment in Error Cases S-CSCF De-Assignment Maintaining S-CSCF Assignment Mechanism for Controlling Bearer Traffic Introduction Gating and QoS Control Traffic Plane Event Reporting Network Initiated Bearer Activation Usage of Rx Reference Point Charging Introduction Charging Architecture Offline Charging Online Charging Flow-Based Charging Charging Reference Points Charging Information Correlation Charging Information Distribution User Profile Introduction Public Identification Core Network Service Authorization Service-Triggering Information Service Provision Introduction Creation of Filter Criteria Selection of AS AS Behaviour Connectivity between Traditional CS Users and IMS Users Introduction IMS-Originated Session Toward a User in the CS Core Network CS-Originated Session Toward a User in IMS IMS Transit Support for Local Dialling Plans IMS Emergency Sessions Introduction and Architecture Emergency Registration Emergency Session Setup SIP Compression Introduction SigComp Architecture Compressing a SIP Message in IMS 104

10 viii Contents 3.19 Combination of CS and IMS Services Combinational Services Introduction Capability Exchange Parallel CS and IMS Services Voice Call Continuity Introduction Voice Call Continuity Functionality Voice Call Continuity Session Initiation and Termination Voice Call Continuity Domain Transfer Procedure Supplementary Services Security Services in the IMS IMS Security Model Authentication Network Domain Security (NDS) IMS Access Security for SIP-Based Services IMS Access Security for HTTP-Based Services Interworking between IPv4 and IPv6 in the IMS Introduction Network Address Translation IPv6-Only Versus Dual Stack Interworking Scenarios Intra-Domain Scenarios Inter-Domain Scenarios Configuration and Bootstrapping IPv4-Only Access Networks 134 PART II IMS SERVICES 4 Presence Who will use the Presence Service? Presence-Enhanced Services Presence Contributing to Business What is Presence? Presence Service in IMS Publishing Presence Subscribing Presence Watcher Information Setting Presence Authorization Group Management Group Management s Contribution to Business What is Group Management? What is XML Configuration Access Protocol? What is Common Policy? Model and Rule Structure 154

11 Contents ix Data Types and Permission Processing Resource List XCAP Usage for Resource Lists Open Mobile Alliance Solution for Group Management Service Specific XML Document Management Servers Shared XML Document Management Servers Multimedia Telephony and Service Management Communication Barring Communication Diversion Originating Identification Services Terminating Identification Services Multimedia Telephony Service Management Example Push to Talk Over Cellular PoC Architecture PoC Server PoC Client PoC Features PoC Communication Simultaneous PoC Sessions PoC Session Establishment Models Incoming PoC Session Treatment Instant Personal Alerts Group Advertisement Barring Features Participant Information User Plane Talk Bursts Talk Burst Control Quality Feedback PoC Service Settings Messaging Overview of IMS Messaging Immediate Messaging Session-Based Messaging Messaging Interworking Instant Messaging by Open Mobile Alliance OMA IM Architecture IM Communication Conversation History Deferred Messaging IM Service Settings IM User-Plane Delivery Reports 218

12 x Contents 8 Conferencing IMS Conferencing Architecture and Principles SIP Focus/Conferencing AS/MRFC Conference Mixer MRFP Conference Participant Conference Moderator, Floor Control and Conference Policy Control Sidebars IMS Conferencing Procedures Conference Creation Joining a Conference Conference State Event Package Floor Control Multimedia Telephony Introduction Multimedia Telephony Communication SIP and IMS Multimedia Telephony IMS Communication Service Identification (ICSI) and Telephony Application Server (TAS) Supplementary Services Communication Barring Communication Diversion Communication Hold Conference Message Waiting Originating Identification Presentation Originating Identification Restriction Terminating Identification Presentation (TIP) Terminating Identification Restriction (TIR) Explicit Communication Transfer 245 PART III DETAILED PROCEDURES 10 Introduction to Detailed Procedures The Example Scenario Base Standards An Example of IMS Registration Overview Initial Parameters and IMS Management Object Signalling PDP Context Establishment P-CSCF Discovery Overview SIP and DNS Server Configuration via DCHPv DNS Naming Authority Pointer (NAPTR) Resolving Transport Protocol Selection and DNS Service (SRV) Resolving DNS IPv6 Address Resolving 260

13 Contents xi Related Standards SIP Registration and Registration Routing Aspects Overview Constructing the REGISTER Request From the UE to the P-CSCF From the P-CSCF to the I-CSCF From the I-CSCF to the S-CSCF Registration at the S-CSCF The 200 (OK) Response The Service-Route Header The Path Header Third-Party Registration to Application Servers Updating the User Profile Related Standards Authentication Overview HTTP Digest and 3GPP AKA Authentication Information in the Initial REGISTER Request S-CSCF Downloads the Authentication Vector (AV) from the HSS S-CSCF Challenges the UE UE s Response to the Challenge Integrity Protection and Successful Authentication Related Standards Access Security IPsec SAs Overview Establishing an SA During Initial Registration Handling of Multiple Sets of SAs in the Case of Re-authentication SA Lifetime Port Setting and Routing Related Standards SIP Security Mechanism Agreement Why the SIP Security Mechanism Agreement is Needed Overview Sip-Sec-Agree-Related Headers in the Initial REGISTER Request The Security-Server Header in the 401 (Unauthorized) Response Sip-Sec-Agree Headers in the Second REGISTER Sip-Sec-Agree and Re-Registration Related Standards IMS Communication Service Identification and other Callee Capabilities Overview Feature Tags: Callee Capabilities IMS Communication Service Identification (ICSI) and IMS Application Reference Identification (IARI) Related Standards and Links Compression Negotiation Overview Indicating willingness to use SigComp comp=sigcomp Parameter During Registration comp=sigcomp Parameter in Other Requests Related Standards 300

14 xii Contents Access and Location Information P-Access-Network-Info P-Visited-Network-ID Related Standards Charging-Related Information During Registration User Identities Overview Public and Private User Identities for Registration Identity Derivation from USIM Default Public User Identity/P-Associated-URI Header Assignment of a Globally Routable User Agent URI UE s Subscription to Registration-State Information P-CSCF s Subscription to Registration-State Information Elements of Registration-State Information Registration-State Information in the Body of the NOTIFY Request Example Registration-State Information Multiple Terminals and Registration-State Information Related Standards Re-Registration and Re-Authentication User-initiated Re-registration Network-Initiated Re-Authentication Network-Initiated Re-Authentication Notification Related Standards De-Registration Overview User-Initiated De-Registration Network-Initiated De-Registration Related Standards GPRS-IMS-Bundled Authentication (GIBA) Example IMS Registration with Fallback to GIBA GIBA Scenarios An Example IMS Multimedia Telephony Session Overview Caller and Callee Identities Overview From and To Headers Identification of the Calling User: P-Preferred-Identity and P-Asserted-Identity Identification of the Called User Related Standards Routing Overview Session, Dialog, Transactions and Branch Routing of the INVITE Request Routing of the First Response Re-transmission of the INVITE Request and the 100 (Trying) Response Routing of Subsequent Requests in a Dialog Standalone Transactions from One UE to Another Routing to and from ASs 349

15 Contents xiii IMS Communication Service Identification Related Standards Compression Negotiation Overview Compression of the Initial Request Compression of Responses Compression of Subsequent Requests Related Standards Media Negotiation Overview Reliability of Provisional Responses SDP Offer/Answer in IMS Related Standards Resource Reservation Overview The 183 (Session in Progress) Response Are Preconditions Mandatorily Supported? Preconditions Establishing the Media Resources and PCC Related Actions Media Policing Related Standards Charging-Related Procedures During Session Establishment for Sessions Overview Inter-Operator Identifier Exchange of ICID for a Media Session Correlation of GCID and ICID Distribution of Charging Function Addresses Related Standards Release of a Session User-Initiated Session Release P-CSCF Performing Network-Initiated Session Release S-CSCF Performing Network-Initiated Session Release Alternative IMS Session Establishment Procedures Overview Session with a Uni-Directional Media Stream and Available Resources on A Side Session with a Uni-Directional Media Stream and Resources Need to be Reserved on A and B Side Resources Available on B Side Only Network Initiated Resource Reservation, Resources Available Only at A-Side Network Initiated Resource Reservation at A Side Resources Available on A Side and B Side Early Media and Reliable Ring-Back Tone Session Towards a Non-IMS SIP Terminal Session From Non-IMS SIP Terminal Related Standards Routing of GRUUs Theresa Registers her Laptop REFER Request in Order to Transfer the Ongoing Call to Theresa s Laptop Setting up the New Call to Theresa s Laptop 417

16 xiv Contents Routing of PSIs Scenario 1: Routing From a User to a PSI Scenario 2: Routing From a PSI to a User Scenario 3: Routing From a PSI to Another PSI A Short Introduction to GPRS Overview Packet Data Protocol (PDP) PDP Context Types An example IMS Voice Call Continuity Procedures Overview Configuring the Clients with Communication Continuity Configuration Parameters Setting up the Initial Call and Call Anchoring Tobias Sets up a CS Call Towards Theresa Anchoring Decision and Routing the CS Call to the MGCF Interworking the CS Call to IMS at the MGCF Forwarding the IMS call to the VCC Application Server (resolving and direct routing of PSI) Anchoring the Call in Tobias s Domain Forwarding the Call to Theresa s Domain Anchoring the call in Theresa s Domain Delivering the Call to Theresa Establishing the End-to-End Call Scenario After Anchoring Domain Transfer: CS to IMS Tobias s Phone Invokes VCC Procedures Routing to Tobias s VCC AS Tobias s VCC AS Performs the CS to IMS Domain Transfer Scenario after CS to IMS Domain Transfer Theresa adds Video to the Call Domain Transfer: IMS to CS Theresa s Phone Starts VCC Procedures From Theresa s Phone to Theresa s VCC AS Performing the IMS to CS Domain Transfer Scenario after IMS to CS Domain Transfer Related Standards 468 References 471 List of Abbreviations 477 Index 487

17 Foreword The telecommunications industry is undergoing a fundamental change and the catalyst for this change is the business models and technologies of the Internet. The ubiquitous use of the Internet Protocol suite (IP) for voice, data, media and entertainment purposes, is driving the convergence of industries, services, networks and business models. Network convergence is the route through which operators facilitate better access to end-user services and applications. IP provides a common foundation offering end-users seamless access to any service, any time, anywhere, and with any device. Full convergence is driven by enabling technologies such as HTTP/SIP, IPv6, VoIP, and the deployment of wireless broadband technologies such as WLAN, CDMA2000, and UMTS/HSPA. The 3 rd Generation Partnership Projects (3GPP and 3GPP2) have taken these developments into account whilst designing the IP-based Multimedia System (IMS). IMS is an overlay service provisioning platform through which telecommunications operators can utilise Internet technologies to their greatest advantage. It operates across fixed and mobile access technologies including WLAN, UMTS/HSPA, and DSL, along with many others. The telecommunications industry has high expectations for IMS. This technology offers the prospect of new value chains and business models for operators on the one side, and the increase of the end-user experience through converged and blended services on the other. This book provides a comprehensive overview of the IMS architecture, its concepts and interfaces, and is an excellent quick reference for IMS practitioners. It tackles questions such as: How can services be implemented with IMS? What are the procedures involved? What do typical call-flows look like?. The authors are recognized contributors to the development and standardization of IMS and, with the first commercial deployments of IMS occurring in various countries, their effort and commitment is starting to pay off. Mika Vehviläinen Chief Operating Officer Nokia Siemens Networks

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19 Preface Internet Protocol (IP) Multimedia Subsystem, better known as IMS, is based on the specification of Session Initiation Protocol (SIP) as standardized by Internet Engineering Task Force (IETF). But SIP as a protocol is only one part of it. IMS is more than just a protocol; it is an architecture for the convergence of data, speech, fixed and mobile networks and is based on a wide range of protocols, most of which have been developed by IETF. IMS combines and enhances them to allow real-time services on top of various kind of packet-switched technologies (GPRS, ADSL, WLAN, Cable, WiMAX, EPS). This book was written to provide a detailed insight into what IMS is i.e., its concepts, architecture, service and protocols. Its intended audience ranges from marketing managers, research engineers, development and test engineers to university students. The book is written in a manner that allows readers to choose the level of knowledge they need and the depth of understanding of IMS they desire to achieve. The book is also very well suited as a reference. The first few chapters in Part I provide a detailed overview of the system architecture and the entities that, when combined, are necessary to provide IMS. These chapters also present the reference points (interfaces) between these entities and introduces the protocols assigned to these interfaces. This part ends with extensive description of essential IMS concepts such as registration, session establishment, policy and charging control, service provisioning, security, IP version interworking. In IMS, services are not limited to audio, but also include presence, group management, Push to talk over Cellular, messaging, conferencing and IMS Multimedia Telephony. In Part II of this book, we introduce these advanced services in IMS, including call flows. This part proves that the convergence of services and networks is not a myth, but will have real added value for the user. SIP and SDP are two of the main building blocks within IMS and their usage gets complemented by a large number of important extensions. Part III goes step by step through an example IMS registration and IMS Multimedia Telephony and Voice Call Continuity at the protocol level, detailing the procedures taken at every entity. Third Generation Partnership Project (3GPP) and IETF have worked together during recent years in an amazing way to bring about IMS and the protocols used by it. We, the authors, have had the chance to participate in many technical discussions regarding the architecture and protocols and are still very active in further discussions on the everimproving protocols and communication systems. Some of these discussions, which often can be described as debates or negotiations, frequently take a long time to conclude

20 xviii The IMS: IP Multimedia Concepts and Services and even more frequently do not result in an agreement or consensus on the technical solutions. We want to thank all the people in these standardization bodies as well as those in our own companies who have come up with ideas, have shown great patience and have worked hard to standardize this communication system of the future called IMS.

21 Acknowledgements The authors of this book would like to extend their thanks to colleagues working in 3GPP and IETF for their great efforts in creating the IMS specifications and related protocols. The authors would also like to give special thanks to the following who helped in the writing of this book providing excellent review comments and suggestions: Erkki Koivusalo, Hannu Hietalahti, Peter Leis, Tao Haukka, Markku Tuohino, Juha Räsänen, Peter Vestergaard, Tapio Paavonen, Kalle Luukkainen, Pavel Dostal, Jozsef Varga, Martin Öttl, Thomas Belling, Ulrich Wiehe, Krisztian Kiss, Hans Rohnert, Antti Laurila and Adamu Haruna. The authors want to especially give thanks to Hisham Khartabil and Aki Niemi for the very good team work and their excellent and major contributions during the first two editions, without which this book would not have been possible. The authors welcome any comments and suggestions for improvements or changes that could be used to improve future editions of this book. Our addresses are:

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23 List of Figures Figure 1.1 IMS in converged networks 4 Figure 1.2 Convergence of networks 6 Figure 1.3 Multimedia messaging 8 Figure 1.4 The role of the IMS in the packet switched networks 9 Figure 1.5 Road to standardized common IMS standards 12 Figure 2.1 IMS connectivity options when a user is roaming 16 Figure 2.2 Overview of IMS security 18 Figure 2.3 IMS charging overview 19 Figure 2.4 IMS/CS roaming alternatives 20 Figure 2.5 IMS and layered architecture 21 Figure 2.6 Access independence 22 Figure 2.7 S-CSCF routing and basic IMS session setup 25 Figure 2.8 Structure of HSS 26 Figure 2.9 Relationship between different application server types 28 Figure 2.10 Signalling conversion in the SGW 29 Figure 2.11 Possible deployments for Interconnection Border Control Function 31 Figure 2.12 IMS architecture 33 Figure 2.13 HSS resolution using the SLF 39 Figure 3.1 High-level IMS registration flow 48 Figure 3.2 Example of implicit registration sets 49 Figure 3.3 High-level IMS session establishment flow 50 Figure 3.4 Relationship of user identities 53 Figure 3.5 Relationship between user identities including shared identity 54 Figure 3.6 Relationship between UE, GRUU and Public User Identities 56 Figure 3.7 Sharing a single user identity between multiple devices 58 Figure 3.8 A GPRS specific mechanism for discovering P-CSCF 59 Figure 3.9 A generic mechanism for discovering P-CSCF 59

24 xxii List of Figures Figure 3.10 Example of S-CSCF assignment 61 Figure 3.11 Policy control entities 62 Figure 3.12 Bearer authorization in UE initiated model 64 Figure 3.13 Example of IMS based gating in the Access Gateway 70 Figure 3.14 Subscription to IMS signaling bearer status 72 Figure 3.15 Bearer authorization in network initiated model 73 Figure 3.16 IMS charging architecture 77 Figure 3.17 Exampleofofflinecharging 79 Figure 3.18 Session- and event-based offline charging example 82 Figure 3.19 Session- and event-based online charging example 83 Figure 3.20 IMS charging correlation 86 Figure 3.21 Distribution of charging information 87 Figure 3.22 Structure of IMS user profile 88 Figure 3.23 Media authorization in S-CSCF 89 Figure 3.24 Shared initial filter criteria 89 Figure 3.25 Structure of initial filter criteria 90 Figure 3.26 Structure of service point trigger 91 Figure 3.27 IMS-CS interworking configuration when an IMS user calls acsuser 95 Figure 3.28 IMS-CS interworking configuration when a CS user calls an IMS user 96 Figure 3.29 IMS transit solution for PSTN/ISDN 96 Figure 3.30 IMS as a general transit network 97 Figure 3.31 Derivation rules for local dialing plans 98 Figure 3.32 IMS emergency session setup 101 Figure 3.33 Signalling compression architecture 104 Figure 3.34 Capability exchange during an ongoing CS call 106 Figure 3.35 Example for parallel connections when combining IMS and CS services 107 Figure 3.36 Voice call continuity and IMS originated call 109 Figure 3.37 Voice call continuity and CS originated call 109 Figure 3.38 Voice call continuity and terminated call 110 Figure 3.39 Domain transfer from CS to IMS 112 Figure 3.40 Domain transfer from IMS to CS 113 Figure 3.41 Security architecture of the IMS 115 Figure 3.42 NASS bundled authentication 117 Figure 3.43 Security domains in the IMS 119

25 List of Figures xxiii Figure 3.44 NDS/IP and SEGs 121 Figure 3.45 Generic bootstrapping architecture 125 Figure 3.46 Application layer gateway in IMS 128 Figure 3.47 Routing based on SIP Outbound flows 130 Figure 3.48 UE discovers reflexive and relayed addresses via STUN/TURN 131 Figure 3.49 Simplified STUN/TURN/ICE flow 132 Figure 3.50 End-to-end and interconnection scenarios 134 Figure 3.51 IPv6 to IPv4 tunnelling mechanism 135 Figure 4.1 Dynamic presence 140 Figure 4.2 Examples of enhanced presence service 141 Figure 4.3 Overview of presence 142 Figure 4.4 Presence architecture 143 Figure 4.5 Presence publication 145 Figure 4.6 Subscription to presence information 146 Figure 4.7 Subscription to watcher information 148 Figure 5.1 XCAP operations 154 Figure 5.2 Common policy data model 155 Figure 5.3 Presence subscription example flow, no RLS 157 Figure 5.4 Presence subscription example flow, with RLS 158 Figure 5.5 Example resource list flow 158 Figure 5.6 OMA XDM architecture 160 Figure 5.7 Storing conversation history metadata and retrieving it 166 Figure 6.1 Push to talk over cellular 176 Figure 6.2 Voice call versus push to talk over cellular 176 Figure 6.3 Push to talk over cellular architecture 177 Figure 6.4 PoC server architecture 178 Figure 6.5 Different PoC communication models 180 Figure 6.6 Pre-established PoC session setup 182 Figure 6.7 On-demand PoC session setup using an unconfirmed mode in the terminating network 183 Figure 6.8 Incoming session treatment decision tree showing impact of access control list and user s answer mode 186 Figure 6.9 User plane Protocol entities 189 Figure 6.10 RTP control Protocol APP packet format 191 Figure 7.1 Instant messaging types 196 Figure 7.2 Immediate messaging flow 196 Figure 7.3 Session-based messaging flow 197

26 xxiv List of Figures Figure 7.4 Example of terminating SMS over IP 199 Figure 7.5 Example of originating SMS over IP 200 Figure 7.6 OMA IM architecture 202 Figure 7.7 OMA IM server architecture 204 Figure 7.8 Originating immediate message in OMA IM 205 Figure 7.9 Terminating immediate message in OMA IM 205 Figure 7.10 Large message mode in OMA IM 206 Figure 7.11 Different IM session types 207 Figure 7.12 OMA IM session initiation 208 Figure 7.13 OMA IM session termination 209 Figure 7.14 Conversation history function 212 Figure 7.15 Store and forward functionality for IM users 214 Figure 7.16 OMA IM user plane 217 Figure 7.17 OMA IM user plane for deferred messaging and conversation history 218 Figure 8.1 IMS conferencing architecture 222 Figure 8.2 Ad-hoc conference creation 224 Figure 8.3 User calling into a conference 226 Figure 8.4 Referring users into a conference via conference AS/MRFC 228 Figure 8.5 Floor control with BFCP 231 Figure 9.1 Example of incoming communication barring supplementary service 236 Figure 9.2 Example of outgoing communication barring supplementary service 237 Figure 9.3 Example of communication diversion supplementary service 238 Figure 9.4 Example of communication hold supplementary service 239 Figure 9.5 Example of conference supplementary service 240 Figure 9.6 Example of explicit call transfer 245 Figure 10.1 The example scenario 250 Figure 11.1 Initial registration flow 254 Figure 11.2 Discovering the P-CSCF via DHCP/DNS 257 Figure 11.3 Routing during registration 270 Figure 11.4 Third party register by S-CSCF 271 Figure 11.5 Authentication information flows during IMS registration 274 Figure 11.6 SA establishment during initial registration 281 Figure 11.7 Two sets of SAs during re-authentication 283 Figure 11.8 Taking a new set of SAs into use and dropping an old set of SAs 284 Figure 11.9 Request and response routing between UE and P-CSCF over UDP 288 Figure Request and response routing between UE and P-CSCF over TCP 288

27 List of Figures xxv Figure Sip-Sec-Agree during initial registration 294 Figure Tobias s subscription to his registration-state information 307 Figure P-CSCF subscription to Tobias s registration-state information 308 Figure User-initiated re-registration (without re-authentication) 314 Figure Network-initiated re-authentication 315 Figure User-initiated de-registration 320 Figure Network-initiated de-registration 320 Figure Example early IMS security flow 329 Figure 12.1 IMS session establishment call flow 332 Figure 12.2 Routing an initial INVITE request and its responses 339 Figure 12.3 Routing of subsequent requests and their responses 348 Figure 12.4 Routing to an application server 351 Figure 12.5 Registration of feature tags 354 Figure 12.6 Routing based on caller preferences 356 Figure 12.7 Routing based on caller preferences: require 358 Figure 12.8 Routing based on caller preferences: explicit 359 Figure 12.9 Routing based on caller preferences: require; explicit 359 Figure SDP offer/answer in IMS 363 Figure SIP, SDP offer/answer and preconditions during session establishment 375 Figure SIP session establishment without preconditions 376 Figure Media streams and transport in the example scenario 380 Figure Worst case scenario for media policing 382 Figure Theresa releases the session 388 Figure P-CSCF terminates a session 388 Figure S-CSCF terminates a session 389 Figure Session establishment resources available at A side 391 Figure Session establishment uni-directional stream with resource reservation on both sides 397 Figure Session establishment resources available at B side 399 Figure Session establishment network initiated resources at B side 401 Figure Session establishment network initiated resources at A side 404 Figure Session establishment resources available on both sides 407 Figure Session establishment early media and ringback tones 409 Figure Session establishment towards a non-ims terminal 411 Figure Session establishment from a non-ims terminal 414 Figure Routing of GRUU 416

28 xxvi List of Figures Figure Routing from a user to a PSI 419 Figure Routing from a PSI to a user 419 Figure RoutingfromanAStoaPSI 420 Figure PDP context types 422 Figure 13.1 Basic interworking of CS and IMS calls at MGCF 430 Figure 13.2 Basic dialog mapping at Tobias s VCC AS (DTF), acting as a SIP B2BUA 431 Figure 13.3 VCC Anchoring simplified call flow 440 Figure 13.4 VCC connections after anchoring 457 Figure 13.5 VCC connections After CS to PS Domain Transfer (A-Side) 463 Figure 13.6 VCC connections After PS to CS Domain Transfer (B-Side) 468

29 List of Tables Table 2.1 Cx commands 36 Table 2.2 Sh commands 39 Table 2.3 Summary of reference points 41 Table 3.1 Information in the PCRF#1 66 Table 3.2 IP QoS class mapping to UMTS QoS 67 Table 3.3 The maximum data rates and QoS class in the PCRF#1 67 Table 3.4 Requested QoS parameters 68 Table 3.5 The maximum authorized traffic class per media type in the UE 69 Table 3.6 The values of the maximum authorized UMTS QoS parameters as calculated by UE #1 (Tobias) from the example 69 Table 3.7 The values of the maximum authorized UMTS QoS parameters as calculated by UE #1 from the example 69 Table 3.8 Rx commands 74 Table 3.9 Summary of offline charging functions 78 Table 3.10 Examples of local dialling strings 100 Table 3.11 Authentication and key agreement parameters 116 Table 6.1 PoC server functional distribution 179 Table 6.2 Summary of different PoC session setup combinations 184 Table 6.3 Mapping of subtype bit patterns to TBCP Protocol messages 192 Table 7.1 OMA IM service settings and possible values 216 Table 10.1 Location of CSCFs and GPRS access for the example scenario 250 Table 11.1 Routing-related headers 261 Table 11.2 Filter criteria in Tobias s S-CSCF 271 Table 11.3 Tobias s public user identities 301 Table 11.4 GIBA registration scenarios 328

30 xxviii List of Tables Table 12.1 Filter criteria in Tobias s S-CSCF 349 Table 13.1 VCC Related Telephone Numbers and Addresses 427 Table 13.2 VCC Related Routing Numbers and SIP Addresses 427 Table 13.3 SIP dialogs at Tobias s VCC AS (B2BUA) 442 Table 13.4 SIP dialogs at Theresa s VCC AS (B2BUA) 450