PERFORMANCE ANALYSIS OF INPUT AND OUTPUT QUEUING PACKET SWITCH WITH MULTIPLE PRIORITY CLASSES

This paper proposes an N x N input-output buffered switch model which switches several kinds of packets emphasizing the real-time property a s well as packets emphasizing the secure transmission. The model corre sponds to the Poisson and Bernoulli traffic switching system. Such per formances as the average system queueing delay and the loss probabilit y for the packet emphasizing the teal-time transmission are analyzed. Nonpreemptive priority discipline is applied on the input side where t he circuit configuration is relatively simple. On the output side, the first-come/first-served (FCFS) process is applied without considering the priority service. In the proposed model, the output buffer size i s assumed as finite and the input buffer size is assumed as infinite. For the two kinds of switching systems which serve the Poisson arrival packets and the Bernoulli arrival packets, respectively, the mean sys tem queueing delay for the priority class is analyzed. For the case wh ere the input buffer size is limited for the packet with a high priori ty emphasizing the real-time transmission, the relation between the lo ss probability for the packet with a high priority and the sizes of th e input and output buffers is investigated by a computer simulation fo r the case of two classes. The adequate input buffer size for the pack et with a high priority is determined.