A Throughput-Enhanced Parallel Scheduling Algorithm for the MIQ Switch with a Moderate Number of Queues

Introduction: In order to overcome the throughput limit of the single input-queued (SIQ) packet switch, a number of bu ering strategies have been put forward in recent years. Among them, the virtual output-queued (VOQ) switch is receiving considerable attention, since it can yield 100% throughput depending on the scheduling algorithm employed. As a special case of the multiple input-queued (MIQ) switch which uses an idea of deploying multiple queues in each input, the VOQ switch equips each input with the same number of queues as the switch size and each queue stores the cells for the same destination. It implies that the VOQ switch eliminates the HOL blocking observed in the SIQ switch and, as the result, leads to the improved performance. Shortcomings of the VOQ switch are (1) that the switch requires N queues when the switch size is N , and (2) that the controller has to manage those queues simultaneously. These cost the implementation of the VOQ switch prohibitively and make the switch infeasible, especially for large dimensions. In addition, the performance enhancement by increasing the number of queues in the MIQ switch is not signi cant when the number of queues is larger than 4 [1, 2]. In reference [1],