Virtual Circuit Blocking Probabilities in an ATM Banyan Network with b×b Switching Elements∗

This paper presents the trade-offs that exist between the blocking probability, the size of the switching elements, the offered load and the link capacities in an ATM-based Banyan multistage interconnection network for QoS-sensitive applications. We present a quasi-analytical study which indicates that, as the link capacity between switching elements is increased, the blocking probability reduces exponentially. We show that, in contrast to what is generally believed, larger switching elements are often, but not always the best design choice. Relevant design recommendations that arise from these results are discussed. The conclusions of this paper are also applicable in non-ATM contexts such as in circuit-switched networks with link-dilated topologies, or photonic switching networks using WDM. Keywords—ATM, blocking performance, Banyan networks, non-blocking networks, multistage interconnection networks.