Preface

Background

Four trends have made a solid understanding of the fundamentals of data communications essential to business and information management students:

• The increasing use of data processing equipment. As the cost of computer hardware has dropped, data processing equipment has become an increasingly important and pervasive part of the office, factory, and engineering environments.
• The increasing use of distributed systems. Dropping hardware costs have resulted in the increasing use of small systems, including servers, workstations, and personal computers. These systems are distributed throughout a business and must be interconnected to exchange messages, share files, and share resources, such as printers.
• The increasing diversity of networking options. The emergence of a broad range of local area network (LAN) standards plus the evolution of LAN technology have led to a broad, overlapping range of products for local area communications. Similarly, the planning for the next generation of telephone equipment and networks and the evolution of new transmission and networking technologies have led to a broad, overlapping range of options for long-distance communications.
• The sudden emergence of the Internet and the World Wide Web. In a very short time, the Internet and especially the World Wide Web have attracted millions of business and personal users. No business can ignore the potential of this enormous facility.

As a result of these factors, business data communications courses have become common in business and information management sequences, and this book intends to address the needs for such a course. However, a focus on data communications is no longer enough.

Over the past twenty years, as data processing capability has been introduced into the office, data communications products and services have gradually assumed increasing importance. Now, technological developments and the widespread acceptance of standards are transforming the ways in which information is used to support the business function. In addition to the traditional communications requirements for voice and data (meaning text and numerical data), there is now the need to deal with pictorial images and video information. These four types of information (voice, data, image, and video) are essential to the survival of any business in today's competitive international environment. What is needed is a treatment not just of data communications but of information communications for the business environment.

Information communications and computer networking have become essential to the functioning of today's businesses, large and small. Furthermore, they have become a major and growing cost to organizations. Management and staff need a thorough understanding of information communications in order to assess needs; plan for the introduction of products, services, and systems; and manage the systems and technical personnel that operate them. This understanding must comprise the following:

• Technology: The underlying technology of information communications facilities, networking systems, and communications software
• Architecture: The way in which hardware, software, and services can be organized to provide computer and terminal interconnection
• Applications: How information communications and networking systems can meet the requirements of today's businesses

Approach

The purpose of this text is to present the concepts of information communications in a way that relates specifically to the business environment and to the concerns of business management and staff. To this end, the book takes an approach based on requirements, ingredients, and applications:

• Requirements: The need to provide services that enable businesses to utilize information is the driving force behind data and information communications technology. The text outlines the specific requirements that this technology is intended to address. This linkage between requirements and technology is essential to motivate a text of this nature.
• Ingredients: The technology of information communications includes the hardware, software, and communications services available to support distributed systems. An understanding of this technology is essential for a manager to make intelligent choices among the many alternatives.
• Applications: Management and staff must understand not only the technology but also the way in which that technology can be applied to satisfy' business requirements.

These three concepts structure the presentation. They provide a way for the student to understand the context of what is being discussed at any point in the text, and they motivate the material. Thus, the student will gain a practical understanding of business information communications.

An important theme throughout the book is the essential role of standards. The proliferation of personal computers and other computer systems inevitably means that the manager will be faced with the need to integrate equipment from a variety of vendors. The only way to manage this requirement effectively is through standards. And, indeed, increasingly vendors are offering products and services that conform to international standards. This text addresses some of the key groupings of standards that are shaping the marketplace and that define the choices available to the decision-maker.

Intended Audience

This book is addressed to students and professionals who now have or expect to have some information communications responsibility. As a full-time job, some readers may have or plan to have responsibility for management of the company's telecommunications function. But virtually all managers and many staff personnel will need to have a basic understanding of business information communications to perform their tasks effectively.

For students, this text is intended as an introductory course in information communications for business and information management students. It does not assume any background in data communications but does assume a basic knowledge of data processing.

The book is also intended for self-study and is designed for use as both a tutorial and a reference book for those already involved in business information communications.

Plan of the Text

This text is a survey of the broad and fast-changing field of information communications. It is organized in such a way that new material is seen to fit into the context of the material already presented. By emphasizing requirements and applications as well as technology, the student is provided with motivation and a means of assessing the importance of a particular topic with respect to the whole. The book is divided into six parts:

• Part One: Requirements—Defines the needs for information communications in the business environment. It discusses the way in which various forms of information are used and the need for interconnection and networking facilities. An examination of the nature and role of distributed data processing is the highlight of this first part.
• Part Two: TCP/IP and the Internet—Provides an overview of the Internet and the basic protocols that are the foundation of the Internet and also addresses the critical issue of quality of service. This part provides a context for much of the material covered in the remainder of the book.
• Part Three: Data Communications Fundamentals—Deals with the basic technology of the communication of information. The emphasis is on digital communications techniques, since these are rapidly displacing analog techniques for all products and services related to information communications. Key topics include transmission media, data link control protocols, multiplexing, and compression.
• Part Four: Networking—Examines the way in which communications facilities are organized into a network. There is a wide variety of options available to the manager and planner; this part presents the range of options and compare their strengths and weaknesses so that the reader can make informed choices based on specific requirements. Both wide area networks (WANs) and local area networks (LANs) are covered.
• Part Five: Applications—Deals with the specific business applications that require information communications facilities and networks. This part presents key applications, such as electronic mail and the World Wide Web. The part closes with a discussion of client/server computing and intranets.
• Part Six: Management Issues—This part examines some of the most important issues that confront the manager with respect to the in-house implementation or the purchase of networking and communications services. It begins with the increasingly important issue of doing business on the Internet. This is followed by a discussion of network management and network security.

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. Finally, a number of real-world cases studies are sprinkled throughout the book.

Note to the Instructor

The major goal of this text is to make it as effective a teaching tool for this exciting and fast-moving subject as possible. This goal is reflected both in the structure of the book and in the supporting material.

The book contains a number of features that provide strong pedagogical support for the instructor. Each chapter begins with a list of chapter objectives, which provides, in effect, an outline of the chapter and alerts the student to look for certain key concepts as the chapter is read. Key terms are introduced in boldface in the chapter, and all of the new key terms for that chapter are listed at the end of the chapter. Acronyms are highlighted and listed on the back endpaper; this is important because the field of information communications is loaded with acronyms. A glossary at the end of the book provides a handy summary of key terms. The summary at the end of each chapter highlights the key concepts and places them in the context of the entire book. In addition, there are questions and homework problems to reinforce and extend what has been learned. The book is also liberally supplied with figures and tables to enhance points made in the text.

Throughout the book a number of case studies are presented. These are not "made-up" or "toy" cases, but actual cases reported in the literature. Each case is chosen to reinforce or extend concepts introduced prior to the case study.

The text is also accompanied by supplementary material that will aid the instructor. A solutions manual provides answers to all of the problems and questions at the end of each chapter. A test bank of additional problems is also available. PDF figures and Powerpoint slides are available on line and on a CD-ROM version of the instructor's manual.

Internet Services for Instructors and Students

There is a Web page for this book that provides support for students and instructors. The page includes links to relevant sites, transparency masters of figures in the book in PDF (Adobe Acrobat) format, Powerpoint slides, and sign-up information for the book's Internet mailing list. The Web page is at WilliamStallings.com. An Internet mailing list has been set up so that instructors using this book can exchange information, suggestions, and questions with each other and with the author. As soon as typos or other errors are discovered, an errata list for this book will be available at WilliamStallings.com/BDC4e.htm.

Note to the Reader

In a book on this topic, for this sort of audience, it is tempting to launch immediately into a description of communications and networking technology and to examine and compare the various approaches. Certainly, this is an essential element of a book that deals with business information communications. However, we believe that this approach is inappropriate. The business reader wants, and rightly so, to see the technical material in the context of the needs of the business and the ways in which communications and networking technology support desired business functions. Thus this book begins by defining the requirements for information communications in business. The types of information and their utility are examined first. This sets the stage for an examination of communications and networking alternatives. And, as these alternatives are presented and compared, the applications for which they are suited, as well as the underlying technology, are explored. It is hoped that this strategy will make the material more comprehensible and provide a structure that is more natural to a reader with a business orientation.

What's New in the Fourth Edition

In the four years since the third edition of this book was published, the field has seen continued innovations and improvements. In this new edition, we try to capture these changes while maintaining a broad and comprehensive coverage of the entire field. To begin the process of revision, the third edition of this book was extensively reviewed by a number of professors who teach the subject and by professionals working in the field. The result is that, in many places, the narrative has been clarified and tightened, and illustrations have been improved. Also, a number of new "field-tested" problems have been added.

Beyond these refinements to improve pedagogy and user friendliness, there have been major substantive changes throughout the book. Highlights include the following:

• TCP/IP and the Internet: A new part has been added early in the book (Part Two) that covers the TCP/IP set of protocols, the Internet, and Internet quality of service. TCP/IP has won the "protocol wars" with OSI and is now the focus of the protocol coverage in this book. Part Two motivates the topics covered in the remainder of the book.
• Wireless networks: Wireless networking, both for local area networks (LANs) and wide area networks (WANs), has become an increasingly important component of many networking configurations. This new edition expands and updates the coverage of wireless technology and networks.
• High-speed LANs: Coverage of this important area is expanded and updated and includes detailed treatment of leading-edge approaches, including Fast Ethernet (100BASE-T), Gigabit Ethernet, and Fibre Channel.
• Business Internets: Innovative uses of Internet technology, including intranets and extranets, have flourished in the business environment. Chapter 17 provides extensive coverage of this important area.
• Quality of Service: Quality of service (QoS) and the related areas of integrated services, differentiated services, and RSVP are introduced in this edition. The implications of these important topics are examined in Chapter 5.
• Network security: The chapter on network security (Chapter 20) has been updated provide a timely presentation that emphasizes the important tools and strategies that management needs to implement. The chapter also includes an extensive discussion of Web security.

In addition, throughout the book, virtually every topic has been updated to reflect the developments in standards and technology that have occurred since the publication of the third edition.

Acknowledgments

Richard Van Slyke of Brooklyn Polytechnic Institute has made substantial contributions to the second and third editions of this book and was listed as a coauthor. Much of his contribution has been retained and revised. In addition, he has contributed new material to this edition.

This new edition has benefited from review by a number of people, who gave generously of their time and expertise. The following people reviewed the fourth edition and made many helpful suggestions: Glenda Dilts of Devry Institute; Qing Hu of Florida Atlantic University; Neil Shaw of the University of Texas–Arlington; Hugo Moortgat of San Francisco State; Mark Pullen of George Mason University; Jim Holden of Clarion University; Peter Mathys of the University of Colorado; Art Dearing of Tarleton State University; and Divakaran Liginla of the University of Wisconsin.

In addition, Professor M. Tamer Ozsu of the University of Alberta and Professor Nalin Sharda of Victoria University of Technology provided detailed reviews of Chapters 2 and 3, respectively, and Zygmunt Haas of Brooklyn Polytechnic reviewed the material on wireless networks.

Professor Varadharajan Sridhar of the Indian Institute of Management contributed the case study on Staten Island University Hospital, and Steven Kilby of AT&T contributed the case studies on ING Life and Archstone.