A threshold based scheduling algorithm for input queue switch

Abstract

Virtual output queueing (VOQ) is an efficient architecture for high-speed switches and router, because it combines the low cost of input queuing with high performance of output queuing. When using VOQ, a scheduler is required to decide the switch sequence of cells. We propose a round-robin based parallel scheduling algorithm (T-RRM) for crossbar switches with input queues to reduce the average delay of cells. In T-RRM, marked port is defined. When a queue sends a cell and the number of queued cells in the queue is bigger than a predicted threshold, the corresponding input and output is marked as marked ports. A marked port will send another cell in next one time slot.