Preplanned restoration of multicast demands in optical networks

The evolution of multicast applications has speeded up. providers have to offer cheap and reliable services for their customers. One way to achieve this is to use a restoration method that provides relatively fast restoration calculated upon a failure, where nearly the minimal amount of resources is allocated. In this paper we propose a new, faster way of restoring multicast demands after link failure that is based on preplaning. We prove its optimality if a few preconditions hold. To do so a new formalization of the wavelength graph transformation (WGT) is presented. We show, based on simulations, that the beneficial properties of our method hold even when one or more preconditions are not kept.