Optical index of fault tolerant routings in WDM networks

Ma nuch and Stacho [7] introduced the problem of designing f-tolerant routings in optical networks, i.e., routings which still satisfy the given requests even if f failures occur in the network. In this paper, we provide f-tolerant routings in complete and complete balanced bipartite optical networks, optimal according to two parameters: the arc-forwarding index and the optical index. These constructions use tools from design theory and graph theory and improve previous results of Dinitz, Ling and Stinson [4] for the complete network, and Gupta, Ma nuch and Stacho [5] for the complete balanced bipartite network.