A distributed scheme for bandwidth reallocation between working and recovery paths

Abstract

This paper presents a model of network failure recovery based on a scheme for reallocating bandwidth in path-oriented transport networks. We first describe the bandwidth reallocation scheme where, at specified time points, bandwidth can be switched to those routes that (possibly temporarily) value it most highly. This is done entirely according to local rules and without centralised control.We next describe our model of network failure recovery. We consider a protection switching recovery model which works with pre-established reserve-on-demand recovery routes. A reserve-on-demand recovery route allocates required resources after a failure on the working path has been detected. The bandwidth reallocation scheme is used to distribute bandwidth between the working routes before and after a failure, and between the working and recovery routes during the recovery cycle.To support the efficacy of such a system, we present a simulation model of failure recovery in a 30-node 46-link network. The simulation study reveals that bandwidth reallocation allows rapid recovery after the failure of a single link. Traffic is restarted on a recovery route within one round trip time and the recovery path attains the same Grade of Service (GoS) as its working counterpart within 0.1 call holding times.