Performance analysis of token ring networks with a reservation priority discipline

An analytical method is developed for a token ring network with single-buffer terminals and an infinite-capacity bridge in which the bridge has priority over the terminals is developed. The priority-mode operation realized by the reservation discipline of IEEE standard 802-5 is considered. An approximate analysis is considered for both terminals and the bridge in two reservation disciplines: the T-reservation discipline in which the reservation field resides in the message trailer, and the H-reservation discipline in which the reservation field resides in the message header. System performance measures (mean waiting times and throughput) derived for these disciplines are compared to those for a mixed discipline which is an alternative method for priority-mode operation in token ring networks. The accuracy of the approximate analytical results is assessed for both terminals and the bridge by comparing them to the simulation results. For almost all tried cases, it is shown to be within 5-20% relative error in the mean message waiting time