Performance analysis for a message priority based polling scheme

Abstract

The authors consider a multiaccess communication channel, such as a token-based ring or bus network. A message priority based polling procedure is used to control access of messages onto the channel. This procedure requires the server to have no advance information concerning the number of messages resident at a station prior to its visit to the station. Messages arriving at each station belong to one of two priority classes: class-1 (high priority) and class-2 (low priority). Class-1 messages are served under an exhaustive service discipline while class-2 messages are served under a limited service discipline. Class-1 messages have nonpreemptive or preemptive-resume priority over class-2 messages resident at the same station. Two different schemes, corresponding to the nonpreemptive and preemptive-resume priority disciplines, respectively, are analyzed. Tight upper and lower bounds for the mean message waiting times for each individual message class are obtained. >