Table of Contents

Glossary.

List of Abbreviations.

1. Introduction.

1.1 The rebirth of VoIP.

1.2 Why beyond VoIP protocols?

1.3 Scope of this book.

1.4 Intended audience.

1.5 Conclusion.

1.6 References.

2. Introduction to Speech-coding Techniques.

2.1 A primer on digital signal processing.

2.2 The basic tools of digital signal processing.

2.3 Overview of speech signals.

2.4 Advanced voice coder algorithms.

2.5 Waveform coders. ADPCM ITU-T G.726.

2.6 Hybrids and analysis by synthesis (ABS) speech coders.

2.7 Codebook-excited linear predictive (CELP) coders.

2.8 Quality of speech coders.

2.9 Conclusion on speech-coding techniques and their near future.

2.10 References.

2.11 Annexes.

3. Voice Quality.

3.1 Introduction.

3.2 Reference VoIP media path.

3.3 Echo in a telephone network.

3.4 Delay.

3.5 Acceptability of a phone call with echo and delay.

3.6 Conclusion.

3.7 Standards.

4. Quality of Service.

4.1 Introduction: What is QoS?

4.2 Describing a data stream.

4.3 Queuing techniques for QoS.

4.4 Signaling QoS requirements.

4.5 The CableLabs® PacketCableTM quality-of-service specification: DQoS.

4.6 Improving QoS in the best effort class.

4.7 Issues with slow links.

4.8 Conclusion.

4.9 References.

4.10 Packet size annex.

5. Network Dimensioning.

5.1 Simple compressed voice flow model.

5.2 Building a network dedicated to IP telephony.

5.3 Merging data communications and voice communications on one common IP backbone.

5.4 Multipoint communications.

5.5 Modeling call seizures.

5.6 Conclusion.

5.7 References.

6. IP Multicast Routing.

6.1 Introduction .

6.2 When to use multicast routing.

6.3 The multicast framework.

6.4 Controling scope in multicast applications.

6.5 Building the multicast delivery tree.

6.6 Multicast-routing protocols.

6.7 The mBone.

6.8 MULTICAST issues on non-broadcast media.

6.9 Conclusion.

6.10 References .

Index.

About the Author

Olivier Hersent is Chairman and CTO of NetCentrex, France (Market Leader in VoIP deployments in Europe).

Jean-Pierre Petit is Head of Voice Technology at France Telecom.

David Gurle is Vice President of Multimedia Communications for Reuters and was previously Head of the Real-Time Communications (VoIP) group at Microsoft.