Abstract: Protection paths are dynamically allocated in a wavelength-division multiplexed network including a plurality of nodes (12) coupled by communication links (14). A database (26) stores information regarding the status of the network including information associating channels in each link of the node to one or more protection paths and information associating channels in each link to respective working paths. Upon receiving a request for a new protection path to protect a defined working path, links are identified that have at least one shareable channel which may be shared between the new protection path and one or more existing protection paths, as are links that do not have a shareable channel but do have an unused channel that may be used for the new protection path. Costs are assigned to identified links where links that have at least one shareable channel are weighted differently that links that do not have a shareable channel. A protection path is determined using the found links based on the costs.

Abstract: A system and method for implementing a shared protection scheme under a scenario of multiple failures in an optical network. In one embodiment of the invention, a working path between an ingress node and an egress node is computed responsive to a connection request received in the network. One or more backup paths are computed between the ingress and egress nodes, which are activatable upon a failure condition associated with the working path or the backup paths. The backup paths may be based on link and/or node disjointedness, as well as resource-based cost constraints.

Abstract: Method and apparatus for dynamic provisioning of reliable connections in the presence of multiple failures in optical networks are described. One embodiment is a method for allocation of protection paths after a failure in an optical network. The method comprises, responsive to a failure in an active lightpath, switching traffic on the active lightpath to a protection path; subsequent to the switching, identifying all active lightpaths in the network that no longer have an available protection path; and attempting to allocate a protection path to each of the identified active lightpaths.