On the Duality Between Routing and

A duality property is established between scheduling and routing problems associated with a set of parallel queues. This allows one to determine the optimal policy for either system, once it is determined for its dual system. Moreover, the evaluation of diierent design alternatives (e.g., allocation of buuers) can also be accommodated in the same duality framework. The limitations and the crucial assumptions in establishing the duality properties (e.g., preempti-veness in scheduling policies) are shown. Various applications are presented. It is shown, for instance, that the Smallest Residual Capacity scheduling policy is optimal, as being the dual of the well-known Shortest Queue routing policy.