Dynamic establishment of restorable connections using pp-cycle protection in WDM networks

Dynamic establishment of restorable connections in WDM networks is an important problem that has received much study. We propose a dynamic restorable connection establishment scheme that uses pp-cycles to protect a connection’s working lightpath. For a given connection request, our scheme first computes a working lightpath and then computes a set of pp-cycles to protect the links on the working lightpath so that the connection can survive any single link failure. The key advantage of the proposed scheme is that it enables fast failure recovery while requiring very simple online computation at connection establishment time. Our scheme consists of three components for connection establishment: offline computation of primary cycles, online computation of the working lightpath, and online computation of pp-cycles for working lightpath protection. Our scheme also includes a connection teardown procedure that computes and releases all pp-cycles that are no longer needed. Simulation study shows that our scheme significantly outperforms an existing pp-cycle-based dynamic restorable connection establishment scheme.