Data and Computer Communicatons [antikvár]

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, as well as providing 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. The discussion is bolstered with examples from existing implementations. • Standards: Standards have come to assume an increasingly important, indeed dominant, role in this field. An understanding of the current status and future direction of technology requires a comprehensive discussion of the role and nature of the related standards. Plan of the Text The book is divided into four parts: I Data Communications: This part is concerned primarily with the exchange of data between two directly-connected devices. Within this restricted scope, the key aspects of transmission, interfacing, link control, and multiplexing are examined. II Wide-Area Networks: This part examines the internal mechanisms and technologies 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 frame relay and ATM. vii