Spanning tree algorithm for spare network capacity

Restorability algorithms need to produce a good logical structure that does not introduce delay and congestion problems. This work uses pre-configuration for a detailed examination of the network and proposes a tree as the logical topology. The algorithm produces a spanning tree from a WDM mesh network that allows for good restorability while assuring a structure with short routing paths. The shortest path method with cost on the links inversely proportional to the spare capacity is used to find maximum capacity paths between the nodes. Preliminary results show that varying the definition of the cost on the links for the shortest path analysis achieves different tradeoffs in network restorability vs. average path length. In some cases the restorability approaches optimum (for a tree structure), while using minimum spare capacity.