Scheduling input-buffered multicast ATM switch

Output contention resolution is a fundamental issue of ATM switch design. Output contention is much more severe in multicasting compared to the unicast counterpart. Previous studies have found that the cell loss probability of multicasting is slightly lower than unicasting. That is mainly because the effective cell arrival rate is reduced when the output load is kept unchanged. The performance of an ATM switch is dictated by the queueing discipline and the contention resolution strategy. In this paper, we present a distributed, reservation based scheduling algorithm in which a virtual queue is maintained for each virtual path/circuit. The scheduling is done on a frame by frame basis. While the input ports are transmitting cells according to the schedule of the current frame, the next frame schedule is computed. The proposed method substantially outperforms the other methods in the moderate to high load region.