1.1 Introduction

Voice over IP (VoIP) has been associated with eye-catching headlines in the media specifically with the expectation of 'free' telephone calls over the Internet. Not surprisingly, voice on the Internet has been forecast to have a substantial effect on traditional long-distance and international markets and there is plenty of evidence [1] to support this claim as a reality. Yet voice over IP, IP telephony and voice over the Internet are among the many terms that have emerged since the mid-1990s to describe various technologies and applications for transporting and setting up voice and multimedia calls over an Internet protocol (IP) based packet data network. The very fact that such a range of terms abound continues to cause much confusion within the industry for all kinds of stakeholders including end users, service providers, equipment manufacturers and policy makers. This has been compounded by the wide-ranging and sometimes subsequently proven to be wildly inaccurate claims about what the technology can offer, the relationship it has with existing services, and the likely future impact upon those services. All of which makes it rather difficult to separate fact from fiction, and 'gold-rush fever' from sensible business opportunity and practice. So what is VoIP and what does it really mean for the communications industry? This book aims to go some way to answering this question by examining the full spectrum of what VoIP could be, should be and currently is.