The increase of bandwidth demand for new Internet applications suggests mapping directly IP over the WDM layer. Since reliability is such a critical issue in these broadband networks, we propose an integrated design method which addresses the problem of survivability as viewed from the IP/MPLS layers but taking into account the failure mechanisms in the optical layer. This approach is becoming practical because of the emergence of GMPLS as a multilayer control plane that can support the signaling required for coordinating the restoration mechanisms in multiple layers.

The model relies on network calculus to evaluate a QoS metric as actually perceived by end users and computes a preplanned restoration scheme to recover from failures. We discuss the numerical implementation, the convergence and the solutions produced by the algorithm and show that the resulting network can provide the prescribed QoS guarantees for all failure states.