Some Inequalities for Parallel-Server Queues

This paper obtains bounds, in terms of the first two moments of the input, on the expected wait in an A/G/k queue with stationary input. To this end, two single-server systems are constructed. The wait in queue for the first single-server system is stochastically larger than the wait in the given multiserver system, and the expected wait in the second single-server system is used to obtain a lower bound on the expected wait in the A/G/k system. The paper also develops, as a consequence of the lower bounds, some results concerning the optimum number of servers, given a fixed work capacity.