Shared-Path Protection for Resource Efficiency

We consider the problem of dynamic survivable lightpath provisioning against single-fiber failures. Specifically, we focus on shared-path protection because of its desirable resource efficiency resulting from backup sharing. Protection approaches to optimizing resource utilization for a given traffic matrix [Crochat et al., 2000, Modiano and Narula-Tam, 2002, Ramamurthy et al., 2003, Van Caenegem et al., 1998] do not apply because lightpath requests come and go in the dynamic provisioning case. Under such a scenario, a network management system needs to compute two link-disjoint paths—a dedicated working path and a shared backup path—for an incoming lightpath request based on the current network state. We concentrate on computing link-disjoint paths for each incoming lightpath request with the assumptions that existing lightpaths cannot be disturbed and no knowledge of future arrivals is available at the time of provisioning this lightpath request. While we consider full wavelength-convertible networks here, the extension to the wavelength-continuous case is straightforward.