Olivier Hersent & Jean-Pierre Petit 
Beyond VoIP Protocols 
Understanding Voice Technology and Networking Techniques for IP Telephony

In 1999-2000, Vo IP (Voice-over-IP) telephony was one of the most successful buzzwords of the telecom bubble era. However, in 2001-2003, Vo IP faced a very tough reality check. Now, manufacturers and service providers are drawing on what they have learnt from past experience in order to prepare to participate in the next major challenge faced by the telecommunications industry.

This book offers a comprehensive overview of the issues to solve in order to deploy global revenue-generating effective ‘multimedia’ services. Drawing on extensive research and practical deployment experience in Vo IP, the authors provide essential advice for those seeking to design and implement a post-bubble Vo IP network.

Beyond Vo IP Protocols: Understanding Voice Technology and Networking Techniques for IP Telephony

* Introduces the basics of speech coding and voice quality

* Demonstrates how quality of service may be built into the network and deals with dimensioning aspects, e.g. multipoint communications and how to model call seizures.

* Explores the potential of multicast to turn an IP backbone into an optimized broadcast medium

* Includes amply illustrated, state-of-the-art practical advice for formulating a complete deployment strategy

A companion volume to ‘IP Telephony: Deploying Vo IP Protocols’, this book takes the reader a stage deeper into how to prepare the network and exploit Vo IP technology to its full potential.

Table of Content

Glossary.

List of Abbreviations.

1. Introduction.

1.1 The rebirth of Vo IP.

1.2 Why beyond Vo IP 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 Vo IP 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 Qo S?

4.2 Describing a data stream.

4.3 Queuing techniques for Qo S.

4.4 Signaling Qo S requirements.

4.5 The
Cable Labs¯® Packet Cable¯TM quality-of-service
specification: DQo S.

4.6 Improving Qo S 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 m Bone.

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 Net Centrex, France (Market Leader in Vo IP 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 (Vo IP) group at Microsoft.