Carrier Grade Voice over IP VOIP技术与应

Preface

*Chapter1　Introduction　1

*Introduction　2

*What Does Carrier Grade Mean?　2

*What Does VolP Mean?　3

*A Little About IP　4

*Why VolP?　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 VolP Market　14

*VolP Challenges　15

?Speech Quality　16

?Network Reliability and Scalability　19

?Managing Access and Prioritizing Traffic　20

*VolP 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

Chapter2　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 Engineering Steering Group(IESG)　36

?The Internet　Assigned Numbers Authority(IANA)　36

?The Internet Standards Process　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 Receiver Report(RR)　67

?RTCP Source Description Packet(SDES)　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　74

?IP Version 6 Header　74

?IP Version 6 Addresses　75

?IP Version 6 Header Extensions　78

?Interoperating IP Version 4 and IP Version6　81

*Other Supporting Functions and Protocols　82

?IP Security　83

?Domain Name Service (DNS)　84

?Path MTU Discovery　85

Chapter3　Speech-Coding Techniques　87

*Introduction　88

*Voice Quality　89

*A Little Abort 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

Chapter4　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

?Alerting　138

?Progress　138

?Connect　138

?Release Complete　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

*Conference Calls　160

?A Pre-Arranged Conference　160

?An Ad-Hoc Conference　160

Chapter5　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

*Examples off SIP Message Sequences　184

?Registration　184

?Invitation　186