This example shows to compare routing policies. The model contains three similar queuing systems in parallel, each with a different routing policy.
This model compares the queuing system under three routing policies given below:
Shortest Queue: Each entity advances to the shortest queue
Probabilistic: Each entity is randomly routed to a queue
Round robin: Entities alternate between the two queues
The plot compares the average system time (end-to-end delay) to show the optimality of the Shortest Queue policy when all service time distributions are exponential. If this assumption is violated, a Shortest Queue policy is not necessarily optimal.