Analysis of packet delay in a GI-G-1 queue with non-preemptive priority scheduling

Priority scheduling for packets is becoming a hot topic, as attemps are being made to integrate voice services in existing IP data networks. In this paper, we consider a discrete-time queueing system with head-of-line (HOL) non-preemptive priority scheduling. Two classes of traffic will be considered, i.e., high priority and low priority traffic, which both generate variable-length packets. We will derive expressions for the Probability Generating Function (pgf) of the packet delay of the high priority traffic and the low priority traffic. From these, some performance measures (such as the mean value) will be derived. These will be used to illustrate the significance of priority scheduling and the effect of nonpreemptive scheduling on the high priority traffic.