HIGH-SPEED LOCAL AREA NETWORKS

This is a semitutorial discussion of high-speed local area networks (L ANs). We begin with a short introduction to the computer evolution fro m mainframes to LANs and characterize the latter in terms of three ele ments, namely, Topology, protocol, and transmission medium. After reca lling the limitations encountered by electric LANs as they approach an d surpass Gb/s data rates, we discuss two of the major problems that w ere recently faced in implementing those data rates with fiberoptic LA Ns, namely, branching losses and coupler directionality. We then proce ed to show how these problems are now resolved with specific component s, particularly, the erbium doped fiber amplifier (EDFA) and the elect ro-optical switchable coupler. We conclude with an analysis of two hig h-speed fiberoptic LANs, in open and closed loop topologies, that util ize these components.