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

ISBN-13: 9780470023624 / Angielski / Twarda / 2005 / 284 str.

Olivier Hersent; Jean-Pierre Petit; David Gurle

Opis

IP telephony, enabled by softswitches, is going to usher in a new telecom era. By putting voice and data over one IP network, operators can enjoy lower costs and create new, revenue-generating 'multimedia' services. What are the advantages of IP Telephony? New entrants to the communications service provider sector must provide data services as well as voice. VoIP dispenses with the need to build two separate networks. Offering a bundled package of services over one network means greater efficiency and higher margins. With broadband fixed and mobile access becoming more prevalent, service providers can offer a whole host of telephony, data and internet services down the one connection. A companion volume to IP Telephony: Deploying VoIP Protocols, this book takes the reader a stage deeper into how to prepare the network and exploit the technology to its full potential. It first introduces the basics of speech coding and voice quality. The authors go on to demonstrate how quality of service may be built into the network and deal with network dimensioning aspects such as multipoint communications and how to model call seizures. A final section on multimedia encoding and transport techn

Spis treści

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^® PacketCable^TM 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.

O autorze

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.

Blurb

In 1999–2000, VoIP (Voice–over–IP) telephony was one of the most successful buzzwords of the telecom bubble era. However, in 2001–2003, VoIP 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 VoIP, the authors provide essential advice for those seeking to design and implement a post–bubble VoIP network.

Beyond VoIP 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 VoIP Protocols", this book takes the reader a stage deeper into how to prepare the network and exploit VoIP technology to its full potential.