Preface

Objectives

This book attempts to provide a unified overview of the broad field of data and computer communications. The organization of the book reflects an attempt to break this massive subject into comprehensible parts and to build, piece by piece, a survey of the state of the art. The book emphasizes basic principles and topics of fundamental importance concerning the technology and architecture of this field and provides a detailed discussion of leading-edge topics.

The following basic themes serve to unify the discussion:

• Principles: Although the scope of this book is broad, there are a number of basic principles that appear repeatedly as themes and that unify this field. Examples are multiplexing, flow control, and error control. The book highlights these principles and contrasts their application in specific areas of technology.
• Design approaches: The book examines alternative approaches to meeting specific communication requirements.
• Standards: Standards have come to assume an increasingly important, indeed dominant, role in this field. An understanding of the current status and future direction requires a comprehensive discussion of the related standards.

Plan of the Text

The book is divided into five parts:

• I. Overview: Provides an introduction to the range of topics covered in the book. In addition, this part includes a discussion of protocols, OSI, and the TCP/IP protocol suite.
• II. Data Communications: Concerned primarily with the exchange of data between two directly connecteddevices. Within this restricted scope, the key aspects of transmission, interfacing, link control, and multiplexing are examined.
• III. Wide Area Networks: Examines the internal mechanisms and user-network interfaces that have been developed to support voice, data, and multimedia communications over long-distance networks. The traditional technologies of packet switching and circuit switching are examined, as well as the more recent ATM. A separate chapter is devoted to congestion control issues.
• IV. Local Area Networks: Explores the technologies and architectures that have been developed for networking over shorter distances. The transmission media, topologies, and medium access control protocols that are the key ingredients of a LAN design are explored and specific standardized LAN systems examined.
• V. Networking Protocols: Explores both the architectural principles and the mechanisms required for the exchange of data among computers, workstations, servers, and other data processing devices. Much of the material in this part relates to the TCP/IP protocol suite.

In addition, the book includes an extensive glossary, a list of frequently used acronyms, and a bibliography. Each chapter includes problems and suggestions for further reading.

The book is intended for both an academic and a professional audience. For the professional interested in this field, the book serves as a basic reference volume and is suitable for self-study. As a textbook, it can be used for a one-semester or two-semester course. It covers the material in the Computer Communication Networks course of the joint ACM/IEEE Computing Curricula 1991. The chapters and parts of the book are sufficiently modular to provide a great deal of flexibility in the design of courses. The following are suggestions for course design:

• Fundamentals of Data Communications: Parts One (overview) and Two (data communications) and Chapters 9 through 11 (circuit switching, packet switching, and ATM).
• Communications Networks: If the student has a basic background in data communications, then this course could cover Parts One (overview), Three (WAN), and Four (LAN).
• Computer Networks: If the student has a basic background in data communications, then this course could cover Part One (overview), Chapters 6 and 7 (data communication interface and data link control), and Part Five (protocols).

In addition, a more streamlined course that covers the entire book is possible by eliminating certain chapters that are not essential on a first reading. Chapters that could be optional are Chapters 3 (data transmission) and 4 (transmission media), if the student has a basic understanding of these topics; Chapter 8 (multiplexing); Chapter 9 (circuit switching); Chapter 12 (congestion control); Chapter 16 (internetworking); and Chapter 18 (network security).

Internet Services for Instructors and Students

There is a Web site for this book that provides support for students and instructors. The site includes links to relevant sites, transparency masters of figures in the book, and sign-up information for the book's Internet mailing list. The Web page is at ...