FTMS: An efficient multicast scheduling algorithm for feedback-based two-stage switch

Two major challenges in designing high-speed multicast switches are the expensive multicast switch fabric and the highly complicated central scheduler. While the recent load-balanced switch architecture uses simple unicast switch fabric and does not require a central scheduler, it is only good at handling unicast traffic. In this paper, we extend an existing load-balanced switch called feedback-based two-stage switch to support multicast traffic. In particular, an efficient multicast scheduling algorithm (FTMS) is designed. With FTMS, head-of-line (HOL) packet blocking at each input port is eliminated by adopting “pointer” queues. To cut down queuing delay, packet replication is carried out at middle-stage ports. As compared with other multicast scheduling algorithms, simulation results show that our FTMS always provides the highest throughput.