Packet Transfer Delays In Local Area Computer Networks*

Abstract

AbstractIn this paper we provide performance comparisons among bus, ring, and star local area networks operating in a short-packet environment. The networks implement packet-switched message communication among a reasonably large number (about 100) of devices (computers, terminals, i/o sensors/drivers, etc.). Two performance measures are studied. Average packet transfer time from a source device buffer to a destination device buffer is derived based on analytic models that have previously been checked by a simulation study. The star system is the overall best and the token bus is the overall slowest under this measure, with the dynamic insertion ring being fastest among the ring protocols. The second performance measure is an upper bound on transfer delay. Under this measure, token and insertion rings, as well as stars, are about equally the best, with the token bus having a bound about 50% larger than those three systems. The slotted rings have a bound that is about k times larger than the best systems, ...