Evaluation of segment-based crankback re-routing for GMPLS-based WSON

The successful creation of lightpaths depends on updated information about network resources, such as the availability of wavelengths in the links along a path and the capability of the nodes to perform wavelength conversion. If signaling is performed with outdated information, a setup request of a lightpath may fail by selecting a path with insufficient network resources. An important GMPLS addition to the RSVP-TE was the possibility of correcting lightpath setup requests using crankback. Crankback extensions permit a node that was unable to forward a setup request to return the blocking information to the upstream nodes. In the segment-based crankback, any of the upstream nodes may attempt to correct the signaling by rerouting the request through an alternate path. Such a strategy, however, is not advantageous for any network topology. In this paper, we evaluate eight different network topologies to determine which network features favor the crankback strategy. To perform our evaluation, we consider several network metrics, including some used in SNA (Social Network Analisys).