Preface xvii
PART I PRELIMINARIES
1 Introduction to VoIP Networks 3
1.1 Public Switched Telephone Network (PSTN) 3
1.2 Fundamentals of Internet technology 7
1.3 Performance issues in the Internet 11
1.4 Quality of Service (QoS) guarantees 12
1.5 Summary 15
2 Basics of VoIP 17
2.1 Packetization of voice 17
2.2 Networking technology 18
2.3 Architecture overview 18
2.4 Process of making a VoIP call 22
2.5 Deployment issues 23
2.6 VoIP applications and services 26
2.7 Summary 27
3 VoIP Codecs 29
3.1 Codec design overview 29
3.2 Speech coding techniques 31
3.3 Narrowband codecs 34
3.4 Wideband and multirate codecs 36
3.5 VoIP softwares 37
3.6 Summary 38
4 Performance of Voice Codecs 41
4.1 Factors affecting VoIP quality 41
4.2 Voice quality assessment 43
4.3 Subjective measures and MOS score 44
4.4 Conversational opinion score 45
4.5 E-Model 46
4.6 Sensitivity to loss 48
4.7 Perceptual Evaluation of Speech Quality (PESQ) 50
4.8 Tools for lab testbed setup 53
4.9 Voice input/output tools 55
4.10 Summary 57
5 VoIP Protocols 59
5.1 Introduction 59
5.2 Signaling protocols 61
5.3 Media transport protocols 70
5.4 Summary 71
PART II VOIP IN OVERLAY NETWORKS
6 Overlay Networks 75
6.1 Internet communication overview 75
6.2 Limitations of the Internet 77
6.3 Overlay networks 78
6.4 Applications of overlay networks 82
6.5 Summary 86
7 P2P Technology 87
7.1 P2P communication overview 87
7.2 Classification of P2P networks 89
7.3 Unstructured overlays 90
7.4 Structured overlays - Distributed Hash Tables (DHTs) 92
7.5 Types of DHT 96
7.6 Semi-structured overlays 100
7.7 Keyword search using DHT 101
7.8 Summary 102
8 VoIP over Infrastructure Overlays 103
8.1 Introduction 104
8.2 VoIP over overlay - generic architecture 104
8.3 Methods to enhance VoIP quality 105
8.4 Estimating network quality 110
8.5 Route computation 114
8.6 Perceived enhancement of VoIP quality 115
8.7 Summary 116
9 VoIP over P2P 119
9.1 VoIP over P2P overlay - generic architecture 119
9.2 VoIP issues in P2P overlay 120
9.3 Case study: Skype 122
9.4 Standardization 130
9.5 Summary 130
PART III VOIP IN WIRELESS NETWORKS
10 IEEE 802.11 Wireless Networks 135
10.1 Network architecture overview 135
10.2 Network access management 137
10.3 Basic medium access protocol 139
10.4 Physical layer 142
10.5 Network resource management 144
10.6 IEEE 802.11 standardization overview 147
10.7 Summary 148
11 Voice over IEEE 802.11 Wireless Networks 149
11.1 VoIP overWLAN performance problems 149
11.2 VoIP capacity 151
11.3 VoIP packet prioritization 155
11.4 Handoff performance 157
11.5 Reliable delivery 160
11.6 Client power management 161
11.7 Issues in mesh networks 161
11.8 Summary 163
12 IEEE 802.16 WiMAX 165
12.1 WiMAX overview 165
12.2 IEEE 802.11 MAC protocol architecture 166
12.3 MAC layer framing 168
12.4 Physical layer 170
12.5 Radio resource management 174
12.6 Competing technologies 175
12.7 Summary 176
13 Voice over WiMAX 177
13.1 Introduction 177
13.2 VoIP service delivery overWiMAX network 178
13.3 QoS architecture 179
13.4 Call admission control 181
13.5 Uplink QoS control 181
13.6 Enhanced QoS control for VoIP 182
13.7 MAC enhancement strategies 185
13.8 Comparison with competing technologies 187
13.9 Summary 187
PART IV VOIP IN ENTERPRISE NETWORKS
14 Private Branch Exchange (PBX) 191
14.1 Private Branch Exchange (PBX) 191
14.2 Case study: Asterisk open-source IP-PBX 195
14.3 Summary 206
15 Network Address Translation (NAT) and Firewall 207
15.1 Introduction 208
15.2 NAT fundamentals 208
15.3 Applications of NAT 210
15.4 Types of NAT 212
15.5 Firewall 214
15.6 NAT traversal solutions 214
15.7 NAT traversal in H.323 219
15.8 Summary 220
PART V VOIP SERVICE DEPLOYMENT
16 Supporting Services and Applications 223
16.1 Domain Name System (DNS) 223
16.2 ENUM 225
16.3 Network monitoring 225
16.4 Direct Inward Dialing (DID) 226
16.5 Emergency calling (911) 226
16.6 Fax 227
16.7 Summary 228
17 Security and Privacy 231
17.1 Security and privacy issues 232
17.2 Generic issues 232
17.3 VoIP-related issues 234
17.4 Solutions 236
17.5 Recommendations 239
17.6 Summary 240
18 IP Multimedia Subsystem (IMS) 241
18.1 Introduction 241
18.2 Architecture design goals 242
18.3 IMS advantages 243
18.4 IMS architecture organization 244
18.5 Network Attachment SubSystem (NASS) 246
18.6 Resource Admission Control Subsystem (RACS) 247
18.7 IMS core subsystem 247
18.8 IMS QoS management 249
18.9 QoS provisioning approach 249
18.10 Summary 251
Index 253
