Performance analysis of token-passing local area networks

A unified performance analysis of token-passing local area networks is reported in this thesis. The primary performance criterion is the mean transfer delay of a message, which is defined as the time from the instant a message becomes available for transmission at a station until the end of its successful reception at the destination. Other performance criteria are power and effective transmission ratio. Analytical expressions for the criteria are derived for exhaustive, gated, and limited service disciplines. Simulation models are also used to support the investigations. The effects of service time distribution (constant, exponential, and hyperexponential) are examined. It is found that under any traffic intensity, service discipline or packet length distribution, token bus gives higher delay and has lower power and lower effective transmission ratio than token ring. Also, the token bus is found to be less sensitive to message length distribution, performing about the same for constant, exponential, and hyperexponential distribution.