PERFORMANCE EVALUATION OF SCHEDULING CONTROL OF QUEUING-NETWORKS - FLUID MODEL HEURISTICS

Motivated by dynamic scheduling control for queueing networks, Chen an d Yao [8] developed a systematic method to generate dynamic scheduling control policies for a fluid network, a simple and highly aggregated model that approximates the queueing network. This study addresses the question of how good these fluid policies are as heuristic scheduling policies for queueing networks. Using simulation on some examples the se heuristic policies are compared with traditional simple scheduling rules. The results show that the heuristic policies perform at least c omparably to classical priority rules, regardless of the assumptions m ade about the traffic intensities and the arrival and service time dis tributions. However, they are certainly not always the best and, even when they are, the improvement is seldom dramatic. The comparative adv antage of these policies may lie in their application to nonstationary situations such as might occur with unreliable machines or nonstation ary demand patterns.