Chapter 4. Voice over the Internet Protocol

  1. David J. Wright

Published Online: 30 JUL 2004

DOI: 10.1002/0470858621.ch4

Voice over Packet Networks

Voice over Packet Networks

How to Cite

Wright, D. J. (2004) Voice over the Internet Protocol, in Voice over Packet Networks, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/0470858621.ch4

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



  • market;
  • IP PBX;
  • IP local exchange;
  • cost;
  • RTP;
  • UDP;
  • frame packing;
  • RTP multiplexing;
  • header compression;
  • RSVP;
  • DiffServ;
  • H.323;
  • SIP;
  • instant messaging;
  • video telephony;
  • unified messaging;
  • VPIM;
  • call walk through;
  • case examples


This chapter starts by identifying markets for VoIP, Voice over the Internet, from the edge to the backbone of the Internet, and their implications for functionality required on voice gateways. The effect of the regulatory situation on VoIP costing is described and compared with the PSTN. VoIP technology is described including packetization using RTP and UDP, QoS using RSVP and DiffServ, and signaling using H.323 and SIP. Integration with web applications and with email and fax are shown to add functionality that would be difficult to achieve with other transport technologies. The chapter concludes with case examples of how VoIP can be used in the desktop, enterprise, ILEC and CLEC networks.