A multiservice high-performance packet switch for broad-band networks

An input queued packet switch for broadband networks that supports data link connections and whose capacity is not constrained by the capacity of a single packet channel is described. The switch bandwidth is allocated at two different times. At connection setup time, an output data link (a channel group) is selected on which some bandwidth is reserved for the new call. At transmission time, specific channels within the data link are optimally allocated, slot by slot, to the packets addressed to that link, solving the output channel contention at the same time. The interconnection network of the switching is basically a Batcher-banyan network including the additional networks required to handle channel groups and to allocate bandwidth fairly at transmission time. Packet sequence integrity can be guaranteed for jitter-sensitive services, as the emulation of a circuit connection. It is shown that the channel group capability of the switch greatly improves the performance of standard input queued packet switches, so that input queuing with suitable data link capacities and output queueing give comparable performances