Samphel Norden, Washington University in St. Louis
Milind M. Buddhikot, Dept. of Network Software Research, Lucent Bell Labs.
Marcel Waldvogel, Washington University in St. Louis
Subhash Suri, Department of Computer Science, Washington University in St. Louis
In this paper, we investigate distributed algorithms for routing of LSPs with backup restoration in the context of static and dynamically reconfigurable label switched networks. Specifically, we propose a new concept of Backup Load Distribution (BLD) Matrix that captures partial network state and eliminates the problems of bandwidth wastage and pessimistic link selection. We describe two new distributed routing algorithms that utilize the BLD matrix and require bounded amount of run time. We can realize these algorithms in the current Intenet architecture using the OSPF extensions for Quality-of-Service (QoS) routing \cite{ospf-extensions} to exchange the proposed BLD matrix among peer routers/switches. Our simulation results for sample realistic topologies show excellent (30-50\%) improvement in number of rejected requests and 30-40\% savings in total bandwidth used for backup connections.