The technology of voice over IP provides for making telephone calls over data networks
such as the Internet and it has now reached critical mass. I know this because
as a technology instructor I spend more and more time teaching Voice over IP or
“VoIP.” I wrote this book because I couldn’t find any material suitable for classroom
use or self-study. There is a good selection of reference books on VoIP; this is
not one of them.
In order to be successful as teaching material, this book needs to meet at least
three criteria. First, the material needs to be organized in a logical way, be of appropriate
technical level for the reader and progress by building upon material that has
been presented in early chapters. Second, feedback in the form of exercises must be
provided so that the learner can judge whether he understands the material provided.
Third, labs need to be included that provide hands-on experience. Hands-on experience
is the most exciting and, dare I say “fun,” part of the learning experience. This
presents challenges when learning about technology that, until recently, has been
confined to the central office of the telephone company. Nevertheless, this challenge
has been met by using programs that can be freely downloaded from the Internet
and are suitable for both classroom use and an individual using a home computer.
This book is divided into three sections: an overview of VoIP, the basics of
TCP/IP, and the technical details of VoIP. The first six chapters provide the introduction
to the technology of VoIP: what it is, the different services based upon it, a
first look at the protocols and what infrastructure is required to support it. These
chapters provide an easy entry for the reader who is anxious to jump in and also for
those who want an overview of VoIP with a minimum of technical detail.