Using aggregation to construct periodic policies for routing jobs to parallel servers with deterministic service times

The problem of routing deterministic arriving jobs to parallel servers with deterministic service times, when the job arrival rate equals the total service capacity, requires finding a periodic routing policy. Because there exist no efficient exact procedures to minimize the long‐run average waiting time of arriving jobs, heuristics to construct periodic policies have been proposed. This paper presents an aggregation approach that combines servers with the same service rate, constructs a policy for the aggregated system, and then disaggregates this policy into a feasible policy for the original system. Computational experiments show that using aggregation not only reduces average waiting time but also reduces computational effort.