A performance analysis of the ATM multiplexer with selective discarding of the cells during congestion

In this paper, we present a discrete-time queuing analysis of the ATM multiplexer fed by independent binary Markov sources with two priority classes of cells. Each source alternates between On, Off periods and each On period consists of a random number of sub-periods. Each sub-period generates geometrically distributed number of cells, first cell of a sub-period is assigned high-priority while remaining cells are assigned low-priority. During normal operation the system delivers both high- and low-priority traffic while during congestion delivers only high-priority cells to their destinations and discard low-priority cells. We determine the performance of the system before and after discarding of the low-priority cells. We determine probability generating function of the queue length in both cases under infinite buffer assumption. Then, the mean delay for infinite buffer and approximate cell loss probabilities for the finite buffer cases are presented as a function of the percentage of the high-priority traffic load.