Scheduling multicast traffic in partially buffered crossbar switches

The tremendous increase of multicast traffic applications on the Internet has led to intensive studies for efficient multicast traffic support in Internet routers and switches. Various solutions have been proposed for the unbuffered (IQ) and buffered (CICQ) crossbar switches. However, they were either too complex to run at high speed or too expensive to be readily implemented in hardware. The Partially Buffered Crossbar (PBC) has been proposed and shown to achieve the performance of buffered crossbars while having a low cost close to that of unbuffered crossbars under unicast traffic. This paper conducts one of the first studies on multicast traffic support in PBC switches and proposes a novel round-robin based scheduling algorithm termed MSRR. Based on extensive simulations, we show that with the proposed algorithm, a PBC switch outperforms its unbuffered and buffered counterparts with a small number of internal buffers, making it highly attractive for next generation networks.