Multicast Scheduling in Buffered Crossbar Switches with Multiple Input Queues

The scheduling of multicast traffic in bufferless crossbar switches has been extensively investigated. However, all the proposed solutions are hardly practical for high capacity switches because of either poor performance or high complexity. A buffered crossbar switch with multiple input queues per input port for transferring multicast traffic is proposed. Under this architecture, the scheduler operates in three stages, namely cell assignment, input scheduling, and output scheduling. The scheduling algorithms with complexity from O(1) to higher are presented for different scheduling stages. Simulation results show that both the number of input queues and the size of crosspoint buffer can affect the throughput performance of a buffered crossbar under multicast traffic. However, under bursty multicast traffic, increasing the number of input queues gains more, no matter which algorithm is used, i.e. either HA-RR-RR with complexity O(1) or MMA-MRSF-LQF with higher complexity. This shows that the proposed scheme is more appropriate for high performance switches.