A large scale ATM switching network with sort-banyan switch modules

A large-scale broadband self-routing switching network based on the three-stage construction of sort-banyan switch modules is proposed. The switching network uses only one kind of module, preserves the cell sequencing of a service, and is robust for all patterns of load on the ports. A multistage three-phase algorithm is designed to control the delivery of cells. The switching network is input queued and delivers at most one cell in a cell time slot to each output port from one of the input ports requesting delivery to that output port. The maximum throughput of the switching network is shown to be 0.458, which is about 78% of that of a single-stage sort-banyan switching network. With a buffer size of 20 cells, one can achieve a 40% loading with almost no buffer overflow. Parallelism is easily achieved by having multiple switching planes. It is shown that, with four switching planes, the network is close to being output-queued