Switch expansion architecture using local switching network

Abstract

We propose a scheme for expanding switch modules to form a larger switch using the so-called local switching obtained by allowing bidirectional connection to the conventional three-stage Clos (1953) network switch. The performance of the proposed expansion architecture was compared to that of the conventional three-stage Clos network. We simulated 32/spl times/32 switching systems using two expansion architectures with the same switching strategy. Experiments show that the average switching latency is reduced by up to 60% in the expansion using the local switching network compared to one using the conventional three-stage Clos network switch. The latency reduction is dependent on the ratio of the delay of the switch fabric to that of the port controller. Expansion using the local switching network reduces latency across the switching system.