This is a practical introduction to the key computing concepts of networks and communications, suitable for a first year undergraduate or industrial course. It provides the foundational knowledge on which to build a fully developed understanding of modern communications methodologies, techniques and standards. It will also be a useful professional reference companion.; The book begins with a general introduction to data communications and the options commonly open to the system designer. It then provides overviews of the key areas in which design decisions must be made: communication media; interface standards; network architectures; modems and multiplexers; network topologies, switching and access control; local area networks; wide-area networks; performance; software issues; security; and implementation.; As a second edition of an established text the book has been thoroughly revised and improved but retains the strengths of the first edition in its clear and well- illustrated exposition. It includes current developments in standards and architecture including ATM, B-ISDN, SNMP, TCP/IP, and other state-of-the- art features of the computer communications world.; In its first edition the book was an authoritative textbook and personal reference for industry. In this new edition it should be even more essential for all with a need for an accessible modern technical introduction to computer communications and networks. Suitable for a practically orientated computer science course at degree level or for an introductory industrial course.