Performance analysis of a multiple-access ring network

The authors model the delay-throughput performance of a class of multiple-access circuit-switched ring local area networks that allow multiple messages to be transferred concurrently on the ring. In particular, they model analytically the PLAYTHROUGH protocol under assumptions of uniform and symmetric traffic, infinite buffers, and a first-in, first-out (FIFO) queueing discipline at each station to predict message mean waiting times that adequately approximate waiting times observed through simulation. The queue is analyzed at an arbitrary station as a M/G/1 vacation system having a Bernoulli schedule with parameter p. Expressions for the vacation duration and p are derived in terms of service times and competing traffic intensities on PLAYTHROUGH rings. The vacation period is modeled as a series of subvacations because the server is allowed to take multiple subvacations when the queue is nonempty. Application of this modeling strategy is shown to provide good agreement between analytical predictions and simulation results. The performance of this class of networks is compared with that of token rings