DELAY PERFORMANCE OF AN INPUT QUEUING PACKET SWITCH WITH 2 PRIORITY CLASSES

The performance of the preemptive priority queueing strategy in an inp ut queueing switch with two priority classes is considered. A new queu eing model is proposed which consists of two independent input buffers with separate head of line (HOL) queues. This model takes account of the priority queue structure as well as the influence of the preemptiv e priority scheme for output contention. By applying the approximation techniques of the flow conservation rule and an equivalent queueing m odel, the authors obtain the queue length distribution, delay and maxi mum throughput in closed-form without using any heuristic adjustments. The results are compared with those of results of Chen and Guerin (19 91), and verified with simulations.