A
system for scheduling multirate
multicast packets through an
interconnection network having a plurality of input ports, a plurality of output ports, and a plurality of input queues, comprising multirate
multicast packets with rate weight, at each input port is operated in nonblocking manner in accordance with the invention by scheduling corresponding to the packet rate weight, at most as many packets equal to the number of input queues from each input port to each output port. The scheduling is performed so that each
multicast packet is fan-out split through not more than two
interconnection networks and not more than two switching times. The
system is operated at 100%
throughput, work conserving, fair, and yet deterministically thereby never congesting the output ports. The
system performs arbitration in only one iteration, with mathematical minimum
speedup in the
interconnection network. The system operates with absolutely no packet reordering issues, no internal buffering of packets in the interconnection network, and hence in a truly
cut-through and distributed manner. In another embodiment each output port also comprises a plurality of output queues and each packet is transferred corresponding to the packet rate weight, to an output
queue in the destined output port in deterministic manner and without the requirement of
segmentation and reassembly of packets even when the packets are of
variable size. In one embodiment the scheduling is performed in strictly nonblocking manner with a
speedup of at least three in the interconnection network. In another embodiment the scheduling is performed in rearrangeably nonblocking manner with a
speedup of at least two in the interconnection network. The system also offers end to end guaranteed bandwidth and latency for multirate
multicast packets from input ports to output ports. In all the embodiments, the interconnection network may be a crossbar network,
shared memory network,
clos network,
hypercube network, or any internally nonblocking interconnection network or network of networks.