The Best Order for Queues in Series

An important design problem for queueing systems is to determine the best order for two or more service stations in series. For given external arrival process and given service-time distributions, the object is to determine the order of the stations (to be used by all customers) that minimizes the expected equilibrium sojourn time per customer. Unfortunately, very little is known about this problem because exact analysis is extremely difficult. This paper applies approximation methods recently developed for networks of queues to obtain approximation formulas and useful heuristic design principles.