Upper bound on blocking probability for vertically stacked optical banyan networks with link failures and given crosstalk constraint

Vertical stacking of multiple copies of an optical banyan network is a novel scheme for building nonblocking optical switching networks. The resulting network, namely vertically stacked optical banyan (VSOB) network, preserves all the properties of the banyan network, but increases the hardware cost significantly under first order crosstalk-free constraint. Therefore, blocking behavior analysis could be an effective approach to studying network performance, and finding a graceful compromise between hardware costs and blocking probability with different degree of crosstalk constraint and link failure probability. However, upper bound on blocking probability for such networks with link failures only has been presented in the literature. In this paper, we present the simulation results for upper bound on blocking probability considering both link-failures and given degree of crosstalk constraint. We find how crosstalk adds a new dimension to the performance analysis of practical VSOB networks where link failures present. The simulation results presented in this paper can guide network designer in finding a tradeoff among the blocking probability, the degree of crosstalk and link failures of VSOB networks.