Patent ID: 8774627

Claim:
A method for designing survivable optical networks that provide end-to-end path restoration to a plurality of demands in the event of a single link or node failure in an optical network using a plurality of preconfigured virtual cycles, where a preconfigured virtual cycle may have a different number of restoration wavelengths on different links and where in the event of a failure each of the affected demands is rerouted onto a single preconfigured restoration route on a segment of a cycle using the number of pre-specified restoration wavelengths required by the demands without resorting to intermediate switching or wavelength conversions on the restoration route, comprising the steps of: (a) generating a plurality of candidate preconfigured virtual cycles (PVC's), and each such PVC restores a plurality of demands in the optical network including demands that have no common failure scenarios, demands that have common failure scenarios and non-overlapping restoration routes, and demands that have common failure scenarios and can share restoration wavelengths with some demand with which there is not a common failure scenario, where a demand can be restored by a preconfigured virtual cycle if both end-nodes of the demand are on the cycle and if there exists a restoration route on a segment of the cycle that has no common failure scenario with a working route of the demand; (b) selecting a set of preconfigured virtual cycles from among all candidate preconfigured virtual cycles so that each of the demands in the optical network is protected by one cycle while achieving a near-minimum total restoration wavelengths cost in the network; (c) resolving wavelength conflicts among restoration routes and demand working routes and among restoration routes on different preconfigured virtual cycles that share one or more links; and (d) incorporating the plurality of selected preconfigured virtual cycles, demands assigned to each of these cycles, and restoration route and restoration wavelengths assigned to each of the demands into the optical network thereby forming a survivable optical network.