The data communications and telecommunications industries are experiencing remarkable growth. One of the forces driving this growth is the asynchronous transfer mode (ATM) technology. Although ATM networks are not widely deployed at this time, they have already generated much curiosity and sparked much debate over how current and new telecommunications services will be offered. In short, ATM has the potential to change the nature of service provisioning in both the data communications and telecommunications industries. This book is based in part on a series of lectures I gave as an introduction to ATM networks. The material came from several sources, including ATM Forum specifications, IETF RFCs and Internet-draft proposals, and ITU-T recommendations. As the title indicates, the book covers the essentials of ATM technology and summarizes the many services being defined over ATM networks. Any reader that is interested in more detailed information on any of the topics covered here should consult more advanced textbooks or the appropriate standards, recommendations, and specifications.

I have tried to simplify the technical details with flow diagrams and examples. I hope that in the process I have maintained the delicate balance between technical correctness and simplicity of presentation. As stated above, the focus of this book is on both ATM technology and the services that can be obtained from that technology. There is often the temptation to stress which of the emerging standards are relevant and which have been implemented. The problem with this line of thinking is that ATM standards are still evolving. A lot of time and resources have been spent by many people to develop these standards. To say that any one standard is not relevant is unfair to the people who have worked so hard on these standards to ensure that ATM succeeds. What has not been implemented today may be implemented tomorrow.

For this reason, and in fairness to the many people who have worked so hard on the different standards committees, this book discusses many of the approved and evolving standards without considering their implementation. Moreover, since implementations are generally vendor specific, an attempt has been made to avoid discussing any implementation issues in order not to favor one vendor over others. In this respect, this book is different from other books on ATM. It presents ATM technology and emerging and approved standards for the different services and leaves it up to the reader to judge what is relevant to him or her and what is not. The first half of the book provides an overview of ATM technology. This includes Chapter 1 through Chapter 8. The second half, which starts at Chapter 9, attempts to explain the services that are being defined for ATM networks. These services include ATM LAN emulation, IP over ATM, multiprotocol over ATM, frame-based access services over ATM, audiovisual multimedia services over ATM, circuit emulation service, and inverse multiplexing over ATM.

Most of these services are still being defined. However, it is my belief that the underlying architectures will not deviate radically from where they are today. Even if they do, the reader will gain enough understanding to follow the changes without being confused. Chapter 1 gives a comprehensive overview of telecommunication and networking basics. It also discusses the evolution of ATM networks, the major forces driving ATM networks, and the market for ATM networks. An extensive glossary of terms is provided at the end of the book. This book is intended for data communications and information systems managers who want a quick reference on ATM networks. The book is also suitable for corporate courses on ATM networks and services.

Because network experts tend to focus on one or two aspects of ATM technology, this book will be an appropriate resource for obtaining a quick overview of ATM networks. Finally, the book can also be used for an introductory graduate course in ATM networks. Many networking technologies have been introduced since the advent of ATM. Some of them will impact ATM network services in one way or another. Two of these technologies are IP switching and the digital subscriber line family of technologies. The impact of IP switching on both the ATM Forum''s multiprotocol over ATM and the IETF''s IP over ATM is discussed briefly in Chapter 11. Similarly, the impact of the digital subscriber line family of technologies on ATM inverse multiplexing service is discussed in Chapter 15. 0201184613P04062001.