Network restoration under link or node failure using preconfigured virtual cycles

A computer readable medium having computer readable program for operating on a computer 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, said program comprising instructions that cause the computer to perform the steps of:

• (a) generating a plurality of candidate preconfigured virtual cycles where each such cycle can restore a plurality of demands in the optical network;
• (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;
• (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 in the optical network to thereby design a survivable optical network.