Chapter 2. Quality of service

  1. David J. Wright

Published Online: 30 JUL 2004

DOI: 10.1002/0470858621.ch2

Voice over Packet Networks

Voice over Packet Networks

How to Cite

Wright, D. J. (2004) Quality of service, in Voice over Packet Networks, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/0470858621.ch2

Author Information

  1. University of Ottawa, Canada

Publication History

  1. Published Online: 30 JUL 2004

Book Series:

  1. Wiley Series on Communications Technology

Book Series Editors:

  1. Professor Barry Evans2 and
  2. Professor David Hutchison3

Series Editor Information

  1. 2

    University of Surrey, UK

  2. 3

    Lancaster University, UK

ISBN Information

Print ISBN: 9780471495161

Online ISBN: 9780470858622



  • service level agreements;
  • quality of service;
  • accuracy;
  • information loss;
  • sender-based control;
  • receiver-based control mechanisms;
  • latency;
  • delay;
  • delay variability;
  • jitter;
  • codec;
  • waveform codec;
  • vocoding;
  • network tuning;
  • over-engineering


Service Level Agreements, SLAs have become essential elements in the contract between a telecommunications service provider and a customer. This chapter shows how Quality of Service, QoS, is an important part of an SLA, and how QoS for voice can in turn be broken down into codec quality, determined at the edge of the network, and latency and information loss characteristics of the network and the edge equipment. The trade-off among these parameters and mechanisms for measuring and controlling them are described, including sender- and receiver-based error control, and prioritization for control of latency. Voice applications requiring different combinations of latency and information loss are identified.