Congestion optimized routing in unidirectional de Bruijn WDM networks in presence of node faults

In this paper the problem of reducing congestion in WDM networks based on unidirectional de Bruijn graphs has been addressed in the presence of node faults. We propose a polynomial time routing algorithm for reducing congestion and analyze its time complexity. Congestion is defined as the maximum of the number of lightpaths propagating through a link over all links in the network. Congestion optimization is important as it leads to optimization of the load ¿_max an important parameter of a lightpath request. Results of the algorithm are shown for de Bruijn networks with various sizes of lightpath requests both in the presence and absence of node faults. Finally we evaluate the performance of the algorithm by comparing the results with those from two other strategies, the greedy routing algorithm and the graph search routing algorithm. Comparisons show that the proposed routing algorithm is the best amongst the three both in the presence and absence of node faults.