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A new approach for fast segment‐based protection in WDM mesh networks

We propose a new approach for developing segment‐based schemes for protection against single link/node failure in wavelength division multiplexing (WDM) mesh networks. In the proposed approach, every request is allocated a pair of link disjoint but most coupled primary and backup paths. Two paths are said to be most coupled if they share the maximum number of end nodes of some existing requests. Coupled paths reduce the total number of hops need to be traversed by a failure signal and, hence, potentially reduces the overall recovery time. We show that the problem of finding a pair of disjoint and most coupled paths is NP‐complete. Accordingly, we propose an efficient and fast protection algorithm called SPXP—Segment Pre‐Cross‐Connected Protection, to allocate disjoint and most coupled paths. The proposed SPXP algorithm reduces the recovery time by ensuring that backup resources are pre‐configured along each backup segment and, hence, is readily available upon a failure. Simulation results for different incremental traffic models and network topologies show that, for most cases, the proposed SPXP exhibits better performance in terms of blocking probability, resource usage, and recovery time compared with existing protection schemes. Copyright © 2010 John Wiley & Sons, Ltd.