Dual scheduling algorithm in a generalized switch: asymptotic optimality and throughput optimality

In this article, we consider the dual scheduling algorithm for a generalized switch. For a saturated system, we prove the asymptotic optimality of the dual scheduling algorithm and thus establish its fairness properties. For a system with exogenous arrivals, we propose a modified dual scheduling algorithm, which is throughput-optimal while providing some weighted fairness among the users at the level of flows. The dual scheduling algorithm motivates a new architecture for scheduling, in which an additional queue is introduced to interface the user data queue and the time-varying server and to modulate the scheduling process, so as to achieve different performance objectives. Further research stemming out of this article includes scheduling with Quality of Service guarantees with the dual scheduler, and its application and implementation in various versions of the generalized switch model.