《Signaling And Switching For Packet Telephony 》

【原书作者】： Matthew Stafford
【译者】：
【ISBN 】： ISBN-10 / ASIN:   1580537367 ISBN-13 / EAN:   9781580537360
【页数 】：274
【开本 】 ：16
【出版社】 ：Artech House Publishers
【出版日期】：2004
【文件格式】：PDF
【封面附图】：
【摘要或目录】：  
Contents
Acknowledgments xiii
CHAPTER 1
Introduction 1
1.1 In the Beginning, There was Voice 1
1.2 Motivation: What Is the Case for Packet Telephony? 2
1.2.1 One Network Versus Two 2
1.2.2 Services 3
1.3 Switch Design 3
1.3.1 Separating Bearer and Control Planes 4
1.4 Motive and Opportunity for Carriers 5
1.5 What Are We Waiting For? 6
1.6 Motivation for this Book 7
PART I
Switching Architectures for Packet Telephony: An Expository Description 9
CHAPTER 2
Essentials of Next Generation Switching 11
2.1 Another Look at the Backhaul Example 12
2.2 Ability to Enter New Markets 13
2.3 Switch Components and Terminology 14
2.3.1 Where Does One Switch Component End and
2.3.1 Another Component Begin? 14
2.4 A Useful Abstraction 15
2.5 Defining the Fabric 16
2.5.1 Do Control Messages Between Media Gateways and
2.5.1 Their Controller Pass Through the Switch Fabric? 17
2.5.2 What Is a Packet? 18
CHAPTER 3
Motivation for Packet Telephony Revisited 21
3.1 Separation of Bearer and Control 21
3.1.1 Open Interfaces 22
3.1.2 Introducing and Maintaining Services 23
v
3.1.3 New Bearer Types 25
3.2 Packet Fabrics 26
3.2.1 Exploiting Routing Intelligence of Packet Networks 26
3.2.2 Exploiting Low Bit-Rate Voice Codecs 29
CHAPTER 4
Signaling and Services 31
4.1 The Control Plane 31
4.2 What Is a Service? 32
4.2.1 Vertical Services 32
4.2.2 Services that Offer Alternative Billing Schemes 33
4.2.3 Short Message Service 33
4.3 Where Do Services “Live,” and What Do They Entail? 33
4.3.1 Can You Say “Database?” 34
4.4 Limitations of Circuit-Switched Networks 35
PART II
Components of Packet Telephony: Technical Descriptions 37
CHAPTER 5
Introduction to Part II 39
5.1 Selected Telco Terminology 40
CHAPTER 6
Protocols 43
6.1 What Is a Protocol Stack? 43
6.1.1 Comparison with Last In, First Out Data Structures 44
6.2 Generic Layer Descriptions 44
6.2.1 Data Link Layer 45
6.2.2 Network Layer 46
6.2.3 Transport Layer 46
6.2.4 A Note on Terminology: Packets and Frames 46
6.2.5 General Comments 47
6.3 Internet Protocol and Transmission Control Protocol 48
6.3.1 What Is an Internet Protocol Router? 48
6.3.2 A Brief Look at TCP 48
6.3.3 TCP/IP Networking Illustration 51
6.3.4 Alternatives to TCP at Level 4: UDP and SCTP 52
6.4 What Is a Finite State Machine? 53
6.4.1 States 54
6.4.2 State Transitions 54
6.4.3 Additional Comments 55
6.5 Signaling System 7 in Brief 55
6.5.1 MTP2 56
6.5.2 MTP3 57
6.5.3 SCCP 57
6.5.4 TCAP 57
vi Contents
6.5.5 MAP 57
6.5.6 ISUP 58
6.6 Summary 60
References 61
CHAPTER 7
A Closer Look at Internet Protocol 63
7.1 The IPv4 Header 64
7.1.1 Fragmentation and Path MTU Discovery 65
7.2 The IPv6 Header 65
7.2.1 IPv6 Extension Headers 66
7.3 Addressing and Address Resolution 67
7.3.1 Conserving IPv4 Address Space 67
7.3.2 The IPv6 Address Space 68
7.3.3 Uniform Resource Identifiers and Domain Name System 69
7.4 Security and AAA 69
7.4.1 Security 69
7.4.2 Authentication, Authorization, and Accounting 70
7.5 Routing 71
7.5.1 Network Optimization 71
7.5.2 Internet Routing Protocols 72
7.5.3 A Link State Protocol: OSPF 72
7.5.4 Distance Vector Protocols: RIP and BGP 73
7.5.5 Routing Protocol Convergence 73
7.5.6 Scalability 75
7.5.7 Trade-offs 75
7.6 Reachability Information 76
7.7 Quality of Service and Statistical Multiplexing 76
7.7.1 What Is Statistical Multiplexing? 77
7.7.2 Differentiated Services 78
7.7.3 Multiprotocol Label Switching 79
7.7.4 “DiffServ at the Edge, MPLS in the Core” 80
7.7.5 Multiservice Networks 80
7.8 Layer 4 Protocols: Suitability to Task 81
7.8.1 UDP 81
7.8.2 Carrying SS7 Traffic over an IP Network: SCTP 82
7.8.3 Comparing and Contrasting TCP with UDP and SCTP 83
7.9 Mobile IP 84
7.10 Summary 84
7.10.1 Further Reading 85
References 85
CHAPTER 8
A Closer Look at SS7 89
8.1 SS7 Architecture and Link Types 89
8.2 SS7 Routing and Addressing 91
8.3 Review of the SS7 Protocol Stack 92
Contents vii
8.4 Message Transfer Part 93
8.4.1 MTP2 94
8.4.2 MTP3 94
8.5 SCCP 95
8.5.1 General Description and Communication with MTP3 95
8.5.2 Getting There Is Half the Fun: Global Title Translation 96
8.6 TCAP 98
8.6.1 Number Portability 99
8.7 MAP 100
8.8 Summing Up 103
8.8.1 Additional Weaknesses of SS7 104
8.8.2 Strengths of SS7 105
References 105
CHAPTER 9
The Bearer Plane 107
9.1 Voice Encoding 107
9.1.1 G.711 107
9.1.2 Why Digital? 108
9.1.3 Other Voice-Encoding Schemes 108
9.2 Bearer Interworking 111
9.2.1 Transcoding 111
9.2.2 Encapsulation of Digitized Sound 111
9.2.3 Packetization Delay and Playout Buffers 113
9.3 Voice over IP 113
9.3.1 Real-Time Services in IP Networks: RTP over UDP 113
References 116
CHAPTER 10
Media Gateway Control and Other Softswitch Topics 119
10.1 Requirements 119
10.1.1 ID Bindings 121
10.2 SDP in Brief 122
10.3 Megaco/H.248 123
10.3.1 Introducing the Megaco Connection Model 123
10.3.2 Terminations 124
10.3.3 Contexts 124
10.3.4 Megaco Commands 125
10.3.5 Example Call Flow 126
10.3.6 Usage of the Move Command 129
10.3.7 Descriptors 130
10.3.8 Sample Megaco Messages 132
10.3.9 Three Way-Calling Example 134
10.3.10 Megaco Miscellanea 136
10.4 MGCP 137
10.4.1 Example Call Flow 137
10.4.2 Brief Comparison with Megaco 138
viii Contents
10.4.3 Other MGCP Verbs 140
10.4.4 Transactions and Provisional Responses 141
10.4.5 MGCP Packages 142
10.5 Interworking with Circuit-Switched Networks 142
10.5.1 Latency Trade-offs 142
10.6 Inhabiting the Bearer, Service, and Control Planes 143
10.7 Signaling Between Two Softswitches 143
10.7.1 BICC 143
References 144
CHAPTER 11
Session Control 145
11.1 “Generic” Session Control 145
11.1.1 Comparison with ISUP Call Flow 147
11.1.2 Modularity in Protocol Design 147
11.2 The H.323 Protocol Suite 148
11.2.1 Heritage of H.323: ISDN 148
11.2.2 H.323 Call Control and Media Control Signaling 149
11.2.3 Talking to the Gatekeeper: RAS Signaling 150
11.2.4 Evolution of H.323 151
11.3 SIP Basics 152
11.3.1 SIP Requests and Responses 154
11.4 SIP Functional Entities 155
11.4.1 Proxy Servers and Redirect Servers 156
11.4.2 Back-to-Back User Agents 157
11.4.3 Registrars 157
References 157
CHAPTER 12
More on SIP and SDP 159
12.1 A Detailed SDP Example 159
12.1.1 Additional Line Types 161
12.2 A Detailed SIP Example 161
12.2.1 Registration Procedures 161
12.2.2 Making a Call 164
12.2.3 The Offer/Answer Model 167
12.3 Forking of SIP Requests 168
12.4 SIP for Interswitch Signaling 168
12.4.1 Comparison with BICC 170
12.5 Additional SIP Methods 170
12.5.1 UPDATEs and re-INVITEs 171
12.6 Resource Reservation and SIP 171
12.6.1 QoS Attributes in SDP 173
12.6.2 More on Parameter Negotiation 174
12.7 SIP-T and Beyond 174
12.8 Authentication and Security 176
12.9 Further Reading 176
Contents ix
References 177
CHAPTER 13
Implementing Services 179
13.1 Introduction 179
13.2 SS7 Service Architectures: Intelligent Network 180
13.2.1 The Global Functional Plane 182
13.2.2 The Distributed Functional Plane 182
13.2.3 IN Capability Sets 183
13.2.4 Limitations and Trade-offs of IN 184
13.3 CAMEL and WIN 185
13.4 Parlay/OSA 185
13.5 JAIN 186
13.6 SIP and Services 186
13.6.1 SIP and Intelligent Networks: PINT and SPIRITS 186
13.7 SIP in Wireless Networks 190
13.7.1 Push To Talk over Cellular 190
13.7.2 SIP Header Compression 191
13.7.3 IP Multimedia Subsystem 192
13.8 Short Message Service 195
13.8.1 SMS in Support of Other Applications 196
13.9 Further Reading 196
References 197
CHAPTER 14
Properties of Circuit-Switched Networks 199
14.1 Telco Routing and Traffic Engineering 199
14.1.1 Truitt’s Model 200
14.1.2 Dynamic Nonhierarchical Routing, Metastable States,
14.1.2 and Trunk Reservation 202
14.1.3 Optional Section: Traffic Intensity and the
14.1.3 Erlang B Formula 203
14.2 Comparison with IP Routing and Dimensioning 205
14.3 Security 206
14.4 Quality of Service 206
14.5 Scalability 207
14.6 Survivability and Reliability 207
14.7 Billing Functionality 207
14.8 Emergency Service and other Government Mandates 208
References 208
CHAPTER 15
Evolving Toward Carrier-Grade Packet Voice: Recent and
Ongoing Developments 209
15.1 QoS and Traffic Engineering in IP Networks 209
15.1.1 Class-Based Queuing 209
15.1.2 DiffServ and IntServ Revisited 210
x Contents
15.1.3 Verifying and Enforcing Traffic Contracts 212
15.1.4 ITU-T and 3GPP QoS Standards 212
15.2 Service-Level Agreements and Policy Control 215
15.3 SDP and SDPng 216
15.4 Sigtran Adaptation Layers 216
15.5 Middlebox Traversal 217
15.6 Comments and Further Reading 219
15.6.1 More on IP QoS 219
15.6.2 IPv6 and ROHC 219
15.6.3 Routing for Voice over IP Protocols: iptel Working Group 221
15.6.4 ENUM 221
15.6.5 Service Architectures 222
References 222
CHAPTER 16
Conclusion 225
APPENDIX A
Data Link Layer Protocols 227
A.1 HDLC 227
A.2 Frame Relay 227
A.2.1 The Frame Relay Header 228
A.2.2 Label Switching and Virtual Circuits 229
A.3 Asynchronous Transfer Mode 230
A.3.1 The ATM Header 230
A.3.2 ATM Approach to Quality of Service and Statistical
A.3.2 Multiplexing 230
A.3.3 The ATM Control Plane 231
A.3.4 ATM Adaptation Layers and Options for Voice over ATM 232
A.3.5 Virtual Paths 234
A.3.6 MPLS over ATM: VC Merge Capability 234
A.3.7 Why Not Voice over ATM? 235
A.4 Ethernet 236
A.4.1 History of Ethernet 237
A.4.2 Ethernet Frame Structure 237
A.4.3 CSMA/CD and Its Scalability Limitations 238
A.4.4 Hubs, Bridges, and Switches 238
A.4.5 Further Reading 240
References 240