Survivability is an important issue in IP-over-WDM networks. IP layer failure recovery is possible only if the IP topology is mapped onto the WDM topology in a survivable way, i.e., the failure of any single fiber will not disconnect the IP topology. This problem has been proven NP-hard in [1]. And an integer linear programming (ILP) formulation that solves this problem is provided in [2]. We p...

In this work we introduce and describe optimal sets of survivable paths defined on an undirected simple graph G. An optimal set of survivable paths in G corresponds to a set of mesh-restored lightpaths in an optical network that minimizes the number of optical channels. We present several fundamental properties of optimal sets of survivable paths in G.

Network restoration is often done at the electronic layer by rerouting traffic along a redundant path. With Wavelength Division Multiplexing (WDM) as the underlying physical layer, it is possible that both the primary and backup paths traverse the same physical links and would fail simultaneously in the event of a link failure. It is therefore critical that lightpaths are routed in such a way t...

A network is said to be survivable if it has sufficient capacity for rerouting all of its flow under the failure of any one of its edges. Here we present a polyhedral approach for designing survivable networks. We describe a mixed–integer programming model, in which sufficient slack is explicitly introduced on the directed cycles of the network while flow routing decisions are made. In case of ...