Global optimisation of routes after the process of recovery

Abstract

Survivability in connection-oriented ATM networks is critical due to link and node failures. With regard to high priority connections, it is important that the network maintains their performance guarantees. The restoration scheme of high priority connections assumes two steps. The first step is the fast restoration to accelerate the recovery of high priority connections through a thick pipe(s) between nodes adjacent to the failed link. Such routes to accommodate thick pipe(s) are sub-optimal due to the urgency of recovery. The second step is that after recovery is completed, the optimisation procedure computes optimal path(s) for new a network topology and moves the thick pipe(s) or part of it to the new optimal path(s). In this paper an overview of route optimisation schemes is discussed. We consider the problem of optimisation of routes (used to re-route high priority connections) after a link failure recovery. The objectives of the optimisation process will be to reduce the percentage of high priority connections supported by a node, maximising the chances of a new connection acceptance and reduction of disruption caused by a link failure.