Chapter 1 Introduction 1
Introduction 2
What Does Carrier Grade Mean? 2
What Does VoIP Mean? 3
A Little About IP 4
Why VoIP? 5
Why Carry Voice? 5
Why Use IP for Voice? 6
Lower Equipment Cost 7
Voice/Data Integration and Advanced Services 9
Lower Bandwidth Requirements 12
The Widespread Availability of IP 13
The VoIP Market 14
VoIP Challenges 15
Speech Quality 16
Network Reliability and Scalability 19
Managing Access and Prioritizing Traffic 20
VoIP Implementations 20
IP-Based PBX Solutions 21
IP Voice Mail 22
Hosted PBX Solutions 22
IP Call Centers 23
IP User Devices 24
Overview of Following Chapters 24
Chapter 2 Transporting Voice by Using IP 29
Introduction 30
Overview of the IP Protocol Suite 31
Internet Standards and the Standards Process 34
The Internet Society 34
The Internet Architecture Board(IAB) 35
The Internet Engineering Task Force(IETF) 35
The Internet Assigned Numbers Authority(IANA) 36
The Internet Standards Process 36
The Internet Engineering Steering Group(IESG) 36
IP 38
The IP Header 38
IP Routing 39
The Transmission Control Protocol(TCP) 44
The TCP Header 45
TCP Connections 47
The User Datagram Protocol(UDP) 49
Voice over UDP, not TCP 51
The Real-Time Transport Protocol(RTP) 52
RTP Payload Formats 53
The RTP Header 57
Mixers and Translators 61
The RTP Control Protocol(RTCP) 62
RTCP Sender Report(SR) 64
RTCP Source Description Packet(SDES) 67
RTCP Receiver Report(RR) 67
RTCP BYE Packet 68
Application-Defined RTCP Packet 69
Calculating Round-Trip Time 70
Calculating Jitter 70
Timing of RTCP Packets 71
IP Multicast 72
IP Version 6 Header 74
IP Version 6 74
IP Version 6 Addresses 75
IP Version 6 Header Extensions 78
Interoperating IP Version 4 and IP Version 6 81
Other Supporting Functions and Protocols 82
IP Security 83
Domain Name Service(DNS) 84
Path MTU Discovery 85
Chapter 3 Speech-Coding Techniques 87
Introduction 88
Voice Quality 89
A Little About Speech 90
Voice Sampling 93
Quantization 94
Types of Speech Coders 96
G.711 97
Adaptive DPCM(ADPCM) 98
Analysis-by-Synthesis(AbS)Codecs 98
G.728 LD-CELP 99
G.723.1 ACELP 101
G.729 103
Selecting Codecs 105
Cascaded Codecs 106
Tones,Signals,and DTMF Digits 107
Chapter 4 H.323 111
Introduction 112
The H.323 Architecture 113
Overview of H.323 Signaling 115
Overview of H.323 Protocols 117
H.323 Addressing 119
Codecs 120
RAS Signaling 120
Gatekeeper Discovery 122
Endpoint Registration and Registration Cancellation 125
Endpoint Location 127
Admission 128
Bandwidth Change 130
Status 132
Disengage 133
Resource Availability 134
Request in Progress 134
Call Signaling 134
Setup 137
Call Proceeding 137
Release Complete 138
Connect 138
Alerting 138
Progress 138
Facility 139
Interaction between Call Signaling and H.245 Control Signaling 139
Call Scenarios 140
Basic Call without Gatekeepers 140
A Basic Call with Gatekeepers and Direct-Endpoint Call Signaling 141
A Basic Call with Gatekeeper/Direct-Routed Call Signaling 142
A Basic Call with Gatekeeper-Routed Call Signaling 144
Optional Called-Endpoint Signaling 146
H.245 Control Signaling 148
H.245 Message Groupings 148
The Concept of Logical Channels 149
H.245 Procedures 149
Fast-Connect Procedure 155
H.245 Message Encapsulation 158
An Ad-Hoc Conference 160
Conference Calls 160
A Pre-Arranged Conference 160
Chapter 5 The Session Initiation Protocol(SIP) 163
Introduction 164
The Popularity of SIP 164
SIP Architecture 165
SIP Network Entities 166
SIP Call Establishment 168
SIP Advantages over Other Signaling Protocols 169
Overview of SIP Messaging Syntax 170
SIP Requests 172
SIP Responses 173
SIP Addressing 176
SIP Addressing 177
Message Headers 177
Registration 184
Examples of SIP Message Sequences 184
Invitation 186
Termination of a Call 188
Redirect and Proxy Servers 188
Redirect Servers 189
Proxy Servers 191
The Session Description Protocol(SDP) 195
The Structure of SDP 195
SDP Syntax 197
Usage of SDP with SIP 203
Negotiation of Media 204
Usage of SIP for Features and Services 206
Call Forwarding 208
Consultation Hold 209
SIP Extensions and Enhancements 211
The SIP 183 Session-Progress Message 212
The SIP INF0 Method 213
The SIP-Supported Header 214
Reliability of Provisional Responses 216
Integration of SIP Signaling and Resource Management 218
Interworking 223
PSTN Interworking 224
Interworking with H.323 227
Summary 231
Chapter 6 Media Gateway Control and the Softswitch Architecture 233
Introduction 234
Separation of Media and Call Control 234
Softswitch Architecture 236
Requirements for Media Gateway Control 238
Protocols for Media Gateway Control 239
MGCP 240
The MGCP Model 241
MGCP Endpoints 241
MGCP Calls and Connections 243
Overview of MGCP Commands 244
Overview of MGCP Responses 249
Command and Response Details 251
Call Setup Using MGCP 257
Call Setup Based on Detected Events 260
MGCP Events,Signals,and Packages 263
Internetworking between MGCP and SIP 264
MGCP Call Release 266
MEGACO/H.248 267
MEGACO Architecture 267
Overview of MEGACO Commands 272
Descriptors 274
Packages 283
MEGACO Command and Response Details 284
Call Setup Using MEGACO 290
MEGACO Call Setup Based on Detected Events 295
Interworking between MEGACO and SIP 301
Chapter 7 VoIP and SS7 303
Introduction 304
The SS7 Protocol Suite 306
The Message Transfer Part 306
ISUP and SCCP 307
SS7 Network Architecture 308
Signaling Points 310
Signal Transfer Point 310
Service Control Point(SCP) 311
Message Signal Units(MSUs) 312
SS7 Addressing 313
The ISDN User Part(ISUP) 314
Performance Requirements for SS7 316
Sigtran 318
Sigtran Architecture 320
SCTP 325
M3UA Operation 337
M2UA Operation 345
Interworking SS7 and VoIP Architectures 347
Interworking Softswitch and SS7 347
Interworking H.323 and SS7 352
Chapter 8 Quality of Service 355
Introduction 356
The Need for QOS 356
End-to-End QOS 358
It s Not Just the Network 359
Overview of QOS Solutions 360
More Bandwidth 360
QOS Protocols and Architectures 361
QOS Policies 365
The Resource-Reservation Protocol(RSVP) 365
RSVP Syntax 366
Establishing Reservations 367
Guaranteed Service 378
Reservation Errors 378
Controlled-Load Service 379
Removing Reservations and the Use of Soft State 380
DiffServ 381
DiffServ Architecture 382
The Need for Service-Level Agreements(SLAs) 383
Per-Hop Behaviors(PHBs) 384
Multi-Protocol Label Switching(MPLS) 387
MPLS Architecture 388
FECs and Labels 390
Actions at LSRs 392
Label-Switched Paths 394
MPLS Traffic Engineering 394
Combining QOS Solutions 401
Further Information 401
Chapter 9 Accessing the Network 403
Modems 404
Introduction 404
ISDN 406
BRI 407
Primary Rate Interface(PRI) 409
The Future of ISDN 409
Digital Subscriber Line(DSL) 410
DSL Variants 411
The ADSL Architecture 415
DSL Modulation 418
DSL Challenges 419
Using the Cable TV Infrastructure 421
Hybrid-Fiber Coax 421
Data Transmission over the HFC Network 422
The Packet Cable Architecture 423
Fixed Wireless Access 425
LMDS 425
Mobile Services 427
The Evolution to 3G for GSM 428
The Evolution to 3G for IS-136 TDMA 431
The Evolution to 3G for IS-95 CDMA 432
Chapter 10 Fax over IP(FoIP) 433
Introduction 434
Today s Fax Service 434
T.4 and T.30 434
Real-Time Fax 438
Sending Fax Messages over IP 440
Fax and H.323 445
TCP or UDP 446
Fax and SIP,SDP,and RTP 447
E-Mail-Based Fax 448
References 451
Glossary 459
Index 467