Converged multimedia networks/ Juliet Bates

Foreword xi
Preface xiii
1 Introduction 1
1.1 Motivation for Network Convergence 1
1.2 The Core Network 2
1.3 Legacy Service Requirements 4
1.4 New Service Requirements 5
1.5 Architectures 6
1.6 Moving to SIP 7
1.7 Growing Revenue 7
1.8 Network Operators ? Dealing with Convergence 9
1.8.1 Scenario 1 ? A Cable Operator 9
1.8.2 Scenario 2 ? A Video-on-demand Service Provider 10
1.8.3 Scenario 3 ? A High-speed Internet Service Provider 11
1.8.4 Scenario 4 ? A Mobile Operator 11
1.8.5 Scenario 5 ? A Fixed Network Operator 13
1.8.6 Scenario 6 ? The PSTN Operator 13
1.9 Enabling Technologies for Converged Networks 14
2 Call Control in the NGN 15
2.1 NGN Network Architectures 16
2.2 The Operation of Call Control 24
2.3 Call Processing in the Legacy PSTN 25
2.4 Call Processing in an NGN Call Agent 28
2.5 The Basic Call State Machine 30
2.5.1 The IN CS-2 Originating BCSM 31
2.5.2 The IN CS-2 Terminating BCSM 34
2.6 Call Signalling in the NGN and the Role of SIP 35
2.6.1 A Brief Discussion of the SIP Architecture and Network Elements 37
2.6.2 A Simple Call Set-up Using SIP Signalling 38
2.6.3 Simple Call Clearing Using SIP Signalling 48
2.6.4 SIP Redirection Servers and SIP Forking 52
2.6.5 Privacy CLI and the SIP P-Asserted-Identity Header 56
2.6.6 SIP Registration Procedures 58
2.6.7 Routing SIP Messages, Record-oute, Route and via Headers 59
2.6.8 SIP Routing in Real Networks 64
2.6.9 The P-Charging-Vector Header 64
2.7 The SDP Protocol 65
2.7.1 An Example Session Description 66
2.7.2 The v =, o =, s = and t = Lines 66
2.7.3 The m = Line (Media Announcement) 67
2.7.4 Static and Dynamic RTP/AVP Payload Types 68
2.7.5 SDP Attribute Lines 69
2.7.6 Building an SDP Answer to and SDP Signalling Conventions in SIP 69
2.8 Media Transport Using RTP and RTCP 71
2.8.1 The RTP Header 71
2.8.2 The RTCP Protocol 72
2.8.3 RTCP Reports 73
2.8.4 RTCP Extended Reports 74
2.8.5 RTP Port Numbers and Symmetric RTP 75
2.9 Addressing Issues 75
2.9.1 The SIP ?tel-URI? 76
2.9.2 Locating Telephone Numbers, ENUM 76
2.10 Summary 77
References 78
3 Securing the Network and the Role of Session Border Gateways 81
3.1 General Principles of Security and the NGN 81
3.1.1 Security Assets 82
3.1.2 Risk Analysis 82
3.1.3 Common Pitfalls 83
3.2 The Problem of Secrets 83
3.2.1 Passwords 83
3.2.2 Shared Secrets 84
3.2.3 Public Key Infrastructure (PKI) 84
3.3 IPSec 85
3.3.1 Key Management 85
3.3.2 Key Distribution 85
3.4 Session Border Controllers and Session Border Gateways 86
3.4.1 Functions of a Session Border Controller 86
3.4.2 Session Border Gateways 89
3.4.3 Gates and Pinholes 90
3.4.4 Preventing Denial of Service Attacks with Session Border Gateways 90
3.4.5 Additional Functions of Session Border Gateways and Session
Border Controllers 92
3.5 Protecting the PSTN Call Control Platforms in the NGN 92
3.5.1 The Importance of Customer Access Type on Security 93
3.5.2 SIP Security Mechanisms 94
3.5.3 The Impact of the Threat Model on Control Plane Security 96
3.6 Summary 97
References 98
4 The NGN and the PSTN 99
4.1 Circuits and What they Carry 99
4.2 Signalling and Supervision 101
4.2.1 Signalling and Supervision on the Access Link 102
4.2.2 Inter-exchange Signalling and Supervision 106
4.3 The Birth of the Call Agent 108
4.3.1 History of an Idea 108
4.3.2 Applying the Architecture 110
4.4 Media Gateways 116
4.5 A Look at Media Gateway Control Protocols 121
4.5.1 SGCP and MGCP 121
4.5.2 The Megaco/H.248 Protocol 126
4.6 The Sigtran Protocols 142
4.6.1 The Stream Control Transmission Protocol (SCTP) 142
4.6.2 User Protocol Adaptive Layers 144
4.7 Summary 146
References 146
5 Evolution of Mobile Networks and Wireless LANs 149
5.1 Introduction 149
5.2 1G and 2G Mobile Networks 151
5.3 Development of 3G 151
5.4 Release 99 UMTS Architecture 152
5.5 General Packet Radio Service (GPRS) 153
5.6 Enhanced Data Rates for GSM Evolution (EDGE) 154
5.7 Release 4 UMTS Architecture 154
5.7.1 Circuit-switched Domain 156
5.7.2 Packet-switched Domain 156
5.8 Wideband Code Division Multiple Access (W-CDMA) 158
5.9 Introduction to IMS 159
5.9.1 The Proxy Call Session Control Function (P-CSCF) 160
5.9.2 The Interrogating Call Session Control Function (I-CSCF) 162
5.9.3 The Serving Call Session Control Function (S-CSCF) 162
5.9.4 IMS Subscriber Identities 164
5.9.5 The Breakout Gateway Control Function (BGCF) 165
5.9.6 The Media Resource Function (MRF) 166
5.10 GPRS Access to IMS 168
5.10.1 Creating a Session 171
5.10.2 Authorisation and Reservation of an IP bearer 173
5.10.3 Storage of Session Paths 173
5.11 Broadband Data Wireless Access 174
5.12 Wireless LAN Interworking 175
5.12.1 3GPP Release 6 Integration of Wireless LANs 176
5.13 Mobile TV and Video 177
5.14 Related Work in other Standards Bodies 179
5.14.1 ETSI 180
5.14.2 ITU-T 181
5.14.3 ATIS 182
5.14.4 IETF 182
Summary 184
Appendix 185
3GPP Specifications 185
3GPP Technical Specifications for MBMS 186
MBMS Bearer Service (Distribution Layer) 186
MBMS User Service (Service Layer): 187
IETF Specifications 187
References 188
6 Value-added Services 191
6.1 Introduction 191
6.2 Service Creation and Delivery Technologies 191
6.2.1 Service Delivery in the PSTN 191
6.2.2 SIP Application Servers 194
6.2.3 Parlay 199
6.2.4 Parlay X 201
6.3 Service Orchestration 205
6.3.1 IMS Model 206
6.3.2 MSF Model 210
6.4 Service Orchestration Examples 217
6.4.1 Service Combination Example ? IMS 217
6.4.2 Conflict Resolution Example ? MSF 221
6.5 Service Delivery Platforms 226
Summary 228
References 228
7 Core Network Architecture 231
7.1 The Convergence Layer: Multiprotocol Label Switching 231
7.1.1 Quality of Service in IP Networks 233
7.1.2 MPLS Traffic Engineering and Traffic Management 234
7.1.3 Signalling and Routing in MPLS Networks 234
7.1.4 Protection, Restoration and Service Assurance in MPLS 236
7.2 Virtual Private Networks 243
7.2.1 Layer 3 Virtual Private Networks 244
7.2.2 Layer 2 Virtual Private Networks 245
7.3 Summary 263
References 264
8 Guaranteeing Quality of Service in the NGN 267
8.1 Introduction 267
8.2 Defining QoS 268
8.3 QoS in IP Networks 269
8.4 Traffic Engineering in the MPLS Core 273
8.5 Video Services 276
8.6 Business VPN Services 278
8.7 Extending QoS for VPN Services across Multiple Providers 279
8.8 QoS and the PSTN 281
8.9 QoS Architectures for PSTN Services 283
8.9.1 A Simple DiffServ-based QoS Solution 283
8.9.2 A Session Border Controller?based Solution with Explicit
Reservations 287
8.9.3 Bandwidth Manager?based Architectures 288
8.10 The MSF Architecture for Bandwidth Management 291
8.10.1 The Bandwidth Management Layer and Scaling the Network 294
8.10.2 Interactions with the Underlying Network 295
8.10.3 Handling Network Interconnect 299
8.10.4 An Alternative Approach to Network Interconnect 300
8.10.5 Signalling QoS Requirements 300
8.10.6 Signalling QoS with SIP Preconditions 303
8.10.7 Bandwidth Reservation Using the Diameter Protocol 306
8.10.8 Challenging Cases and Responding to Network Failures 312
8.10.9 A Call Set-up with Guaranteed QoS Using Bandwidth Managers 314
8.10.10 End-to-end QoS, Spanning Multiple Networks 316
8.10.11 Supporting IMS-based Networks 318
8.11 Protecting the Network from Application Layer Overload 320
8.11.1 Principles of Control Plane Overload 321
8.11.2 Control Plane Overload Control in the PSTN 322
8.11.3 An Overview of Control Plane Overload Control in the NGN 324
8.11.4 Congestion Control Mechanisms Required for Black Phones and
Access Gateways 325
8.11.5 Trunking Gateway Overload Protection Mechanisms 327
8.11.6 A Framework for SIP Overload Control 327
8.11.7 A Protocol-independent Approach (GOCAP) 328
8.12 Summary 328
References 329
Index 333