Some studies on path protection in WDM networks

Path protection in WDM networks is one of the popular ways to design resilient WDM networks. Although complete ILP formulations for optimal design of WDM networks have been proposed in literature, the computational cost of actually solving such formulations make this approach impractical, even for moderate sized networks. This high computational cost arises mainly due to the large number of integer variables in the formulations, which increases the complexity exponentially. As a result, most practical solutions use heuristics, which do not provide any guarantees on the performance. In this article, we propose two novel ILP formulations, which drastically reduce the number of integer variables compared to existing ILPs. This leads to much more efficient formulations. We also present a simple heuristic that may be used for larger networks for which ILP formulations become computationally intractable.