VoIP: Wireless, P2P and New Enterprise Voice over IP

Samrat Ganguly currently works as a Research Staff Member at NEC Laboratories America. He gained his PhD in Computer Science from Rutgers University. His research interests include VoIP over wireless mesh networks, streaming over 3G networks, Grid computing, and QoS issues. He has presented papers for conferences and workshops such as Infocom, PIMRC, and ICC. Sudeept Bhatnagar works as a Research Staff Member at NEC Laboratories America. His research interests include VoIP and Enterprise networks, data streams, wireless mesh technologies and energy-efficient protocol design for sensor networks. He gained his PhD in Computer Science from Rutgers University.? He has published over 20 papers in the area of networking and won the best paper award at the High Performance and Switching and Routing workshop.

Preface. PART I PRELIMINARIES. 1 Introduction to VoIP Networks. 1.1 Public Switched Telephone Network (PSTN). 1.1.1 Switching. 1.1.2 Routing. 1.1.3 Connection hierarchy. 1.1.4 Telephone numbering. 1.1.5 Signaling. 1.1.6 Summary. 1.2 Fundamentals of Internet technology. 1.2.1 Packetization and packet-switching. 1.2.2 Addressing. 1.2.3 Routing and forwarding. 1.2.4 DNS. 1.3 Performance issues in the Internet. 1.3.1 Latency. 1.3.2 Packet loss. 1.3.3 Jitter. 1.4 Quality of Service (QoS) guarantees. 1.4.1 Integrated services. 1.4.2 Differentiated services. 1.4.3 Other modifications. 1.4.3.1 Route pinning. 1.4.3.2 Packet classification. 1.4.4 Admission control. 1.4.5 Status. 1.5 Summary. 2 Basics of VoIP. 2.1 Packetization of voice. 2.2 Networking technology. 2.3 Architecture overview. 2.3.1 Architectural requirements. 2.3.2 Functional components. 2.3.2.1 VoIP calling device. 2.3.2.2 Gateway. 2.3.2.3 Media server. 2.3.2.4 Session control server. 2.3.3 Protocols. 2.4 Process of making a VoIP call. 2.5 Deployment issues. 2.5.1 VoIP quality and performance issues. 2.5.2 Delay. 2.5.3 Jitter. 2.5.4 Packet loss. 2.5.5 Echo and talk overlap. 2.5.6 Approaches to maintaining VoIP quality. 2.5.6.1 Network-level QoS. 2.5.6.2 VoIP codecs. 2.6 VoIP applications and services. 2.6.1 Fax. 2.6.2 Emergency numbers. 2.6.3 Roaming. 2.6.4 Voice over IM. 2.6.5 Push-to-talk. 2.6.6 Conferencing. 2.6.7 Integration with other applications. 2.7 Summary. 3 VoIP Codecs. 3.1 Codec design overview. 3.1.1 VoIP codec design goals. 3.2 Speech coding techniques. 3.2.1 Waveform codecs. 3.2.1.1 Pulse code modulation (PCM). 3.2.1.2 Differential PCM (DPCM). 3.2.2 Source coding. 3.2.3 Hybrid coding. 3.2.4 Adaptive multirate. 3.3 Narrowband codecs. 3.3.1 PCM-based G.711. 3.3.2 ADPCM-based G.721 codecs. 3.3.3 RPE-based GSM codec. 3.3.4 Low-delay CELP-based G.728 codec. 3.3.5 DoD CELP-based G.723.1 codec. 3.3.6 CS-ACELP-based G.729 codec. 3.3.7 iLBC. 3.3.8 Comparison of narrowband codecs. 3.4 Wideband and multirate codecs. 3.4.1 Adaptive MultiRate WideBand (AMR-WB). 3.4.2 Speex. 3.5 VoIP softwares. 3.5.1 Linphone. 3.5.2 SJphone. 3.5.3 Skype. 3.5.4 RAT. 3.6 Summary. 4 Performance of Voice Codecs. 4.1 Factors affecting VoIP quality. 4.1.1 Effects due to encoding. 4.1.2 Effects on the decoder. 4.1.3 Monitoring network conditions. 4.2 Voice quality assessment. 4.3 Subjective measures and MOS score. 4.3.1 Absolute Category Rating (ACR). 4.3.2 Degradation Category Rating (DCR). 4.3.3 Comparison Category Rating (CCR). 4.4 Conversational opinion score. 4.5 E-Model. 4.5.1 Sensitivity to delay. 4.6 Sensitivity to loss. 4.7 Perceptual Evaluation of Speech Quality (PESQ). 4.7.1 PESQ analysis for VoIP codecs. 4.7.2 Cross correlation. 4.8 Tools for lab testbed setup. 4.8.1 Network emulator. 4.9 Voice input/output tools. 4.9.1 Recording tools. 4.9.2 Experiment configurations. 4.10 Summary. 5 VoIP Protocols. 5.1 Introduction. 5.2 Signaling protocols. 5.2.1 Session Initiation Protocol (SIP). 5.2.1.1 Architecture overview. 5.2.1.2 SIP components. 5.2.1.3 SIP operation. 5.2.2 Session Description Protocol (SDP). 5.2.3 H.323. 5.2.3.1 H.323 architecture overview. 5.2.3.2 H.323 components. 5.2.3.3 H.323 protocols. 5.2.3.4 H.323 operation. 5.2.4 Media Gateway Control Protocol (MGCP). 5.2.4.1 Components. 5.2.4.2 Architecture overview. 5.2.4.3 MGCP operation. 5.3 Media transport protocols. 5.3.1 Real-time Transport Protocol (RTP). 5.4 Summary. PART II VOIP IN OVERLAY NETWORKS. 6 Overlay Networks. 6.1 Internet communication overview. 6.1.1 Communication operations. 6.1.2 Communication roles. 6.1.3 Internet routing. 6.1.4 Client-server architecture. 6.2 Limitations of the Internet. 6.3 Overlay networks. 6.3.1 Types of overlay network. 6.3.1.1 Infrastructure overlays. 6.3.1.2 P2P overlays. 6.3.1.3 Design considerations for infrastructure versus P2P overlays. 6.3.2 Routing in overlay networks. 6.4 Applications of overlay networks. 6.4.1 Content distribution network. 6.4.2 Overlay multicast. 6.4.3 Anony