Performance of fast routing algorithm for Vertically Stacked Optical Banyan networks with link failures and given crosstalk constraint

For faster connection establishment, previously proposed Pruned Vertically Stacked Optical Banyan (P-VSOB) networks used plane fixed routing (PFR) algorithm, and has O(log₂N) routing complexity. Blocking probability has also been analyzed for these kinds of networks with given amount of crosstalk. In EP-VSOB networks, a few regular banyan planes are added with the PVSOB networks. Necessary routing algorithm, namely, PFR_LS and PFR_RS show that this switching network can reduce the blocking probability to very low value while keeping the hardware cost almost the same as that of PVSOB networks. Both these algorithm also have the time complexity O(log₂N). This paper deals with the blocking behavior of EP-VSOB (Extended pruned VSOB) networks having link-failures and allows crosstalk constraint. Our simulation results show that crosstalk adds a new dimension to the performance analysis of practical EP-VSOB networks where some links are failed. The results show that if we allow some CSEs to the network then blocking probability decreases to low value for both PFR_LS and PFR_RS algorithm. The results also show that the blocking probability of the EP-VSOB networks does not always increase with the increase of link-failures; blocking probability decreases for certain range of link-failures, and then increases again.