Voice over Packet Networks

Abstract

From the Book: This book presents the state of the art in packet voice. It is designed for readers who are studying and working in the forefront of the fast moving telecommunications industry. As such it is designed for readers who need information fast. The book streamlines its presentation of the subject matter by using the following techniques: It is a short book. The phraseology is very concise. There is no fluff. The format of the text uses extensive headings, subheadings and lists of points so that the reader can rapidly scan for the information that is relevant to their needs. Diagrams are used extensively, since a picture often adds clarity to a concise textual description and since telecommunications is a visual subject. There is no point in understanding a technology unless it is related to a network diagram. The style of writing is changed throughout the text from formal to informal and back to formal again, in order to provide the reader with some variety. This book combines business and technology aspects of packet voice. It is primarily a technology book with about 20% of the content related to business issues. This is a balance that the author has found to be required by professionals in an industry which is primarily technology-based and where an in-depth appreciation of business issues must be founded on an understanding of the technology. The book is designed to provide a bridge between circuit-based and packet-based tele phony. For readers with a background in the circuit switched telephone network, it provides an introduction to each of the packet technologies in addition to describing how those technologies can be used to transport voice. For readers with a background in packet-based data communications, it provides an introduction to voice coding, features and QoS requirements as well as showing how voice can be transported over packet networks. The book is organized in three parts: Part I describes issues related to packet transport of voice that are independent of the transport technology. Part 2 provides a chapter on each of the transport technologies: IP, ATM and frame relay and shows how voice is transported in each case. A final chapter provides an executive summary comparing the strengths and weaknesses of each technology. Part 3 uses the information from Parts 1 and 2 to describe how certain technologies can be combined to provide voice over broadband packet access networks.