Ethernet: Building a Communications Infrastructure

From the Book: Preface: Computer systems and terminal networks which operate in isolation are largely a thing of the past. With the ever increasing power of PCs and workstations and the ever growing importance of operations based on distribution cooperation, local area networks (LANs) have become an indispensable component of the essential communication infrastructure. More than two million LANs have been installed worldwide. The majority of these are based on Ethernet technology; hence the reason for this book on Ethernet-based communication structures. However, beyond a consideration of LAN access protocols and physical network structures, the potential benefits of LANs as part of the enterprise network should also receive due attention. The title of the book reflects this emphasis. It is intended to show that, as a basis for in-house communication, Ethernet is still a key technology. By virtue of its widespread use and the large variety of media and protocols supported, Ethernet is more than just another type of LAN. The broad range of applications and the extensive facilities for forming sub networks and linking to public networks have made Ethernet an appropriate basis for a modern communication infrastructure. The widespread use of workstations in all commercial and scientific sectors and the new service structures based on client-server concepts, together with the increasing trend towards UNIX, have not only strengthened the position of Ethernet as the predominant type of LAN but have also sharply increased the demand for telecooperation at all levels. The themes of network integration (LAN internetworking) and LAN applications, and as a consequence and a prerequisite that ofLANmanagement, are increasingly important. Thus, in addition to the detailed presentation of Ethernet standards and components, particular emphasis has been given to these topics. We have more than a decade of Ethernet experience, and are responsible for large production networks based on Ethernet. Thus, when describing this subject area, practical aspects are close to our hearts. Because of the ephemeral nature of many products, we often found it more appropriate to include a basic discussion of the fundamental operating modes of hardware and software components rather than a product-oriented description. The book is structured such that the initial description of the underlying theory and standards is followed by a discussion of their practical relevance, including examples of typical applications. Thus, the book may be used as both a text and a reference book. Each chapter begins with an introduction describing its structure; these introductions represent both the central theme of the book and a detailed chapter summary. Overall, a certain prior knowledge of data communication terminology and applications is assumed. A book such as this cannot be written without encouragement from others. Thanks are due to our colleagues at the Leibniz Computer Centre of the Bavarian Academy of Sciences and the Munich Network Management Team: these are the environments in which we have gained most of our experience. We should also like to thank all our other friends and colleagues who have supported us throughout with advice and assistance. We mention in particular, Ingrid Fromm, Dipl. -Phys. for providing us with the IEEE papers, Dr. Peter Chylla for his helpful cooperation and valuable preparatory work, and Dr. Sebastian Abeck for his many ideas. We also thank out families for their great patience. Heinz-Gerd Hegering Alfred Lapple Munich, May 1993