Segmented protection path provisioning for capacity optimization in WDM mesh networks

We consider the problem of routing and wavelength assignment (RWA) of segmented protection lightpaths in all-optical wavelength division multiplexing (WDM) networks under single link and node failures for static traffic demand. We develop integer linear programming (ILP) formulations for dedicated and shared segmented protection schemes under single link/node failure for static traffic demand with two different objective functions: (1) minimize the total capacity required for a given traffic demand while providing 100% protection for all the traffic demands; (2) given a certain capacity, maximize the number of demands accepted while providing 100% protection for accepted connections. The numerical results obtained from CPLEX indicate that shared segmented protection (SSP) provides significant savings (up to 41%) in capacity utilization over dedicated and shared end-to-end protection schemes; dedicated segmented protection (DSP) provides marginal savings (up to 39%) in capacity utilization over dedicated and shared end-to-end protection schemes. The numerical results also indicate that shared segmented protection achieves the best performance followed by dedicated segmented protection and shared end-to-end protection, w.r.t. the number of requests accepted, given the network capacity.