Optical network design and restoration

The explosion of data traffic and the availability of enormous bandwidth via dense wavelength division multiplexing (DWDM) and optical amplifier (OA) technologies make it important to study optical layer networking and restoration. This paper is concerned with fast distributed restoration and provisioning for generic mesh-based optical networks. We consider two problems of practical importance: determining the best restoration route for each wavelength demand, given the network topology and the capacities and primary routes of all demands, and determining primary and restoration routes for each wavelength demand to minimize network capacity and cost. The approach we propose for both problems is based on precomputing. For each problem, we describe specific algorithms used for computing routes. We also describe endpoint-based failure detection, message flows, and cross-connect actions for execution of fast restorations. Finally, we report test results for large carrier-scale networks that include both the computational performance of the optimization algorithms and the restoration speed obtained by simulation. Our results indicate that subsecond restoration, high capacity efficiency, and scalability can be achieved without fault isolation and with moderate processing. We also discuss methods for scaling algorithms to problems with very large numbers of demands. The wavelength routing and restoration algorithms, the failure detection, and the message exchange and activation architectures we propose are collectively known as WaveStar™ advanced routing platform.