Enhancing Preventive Start-time Optimization considering both failure and non-failure scenarios

This paper proposes a Preventive Start-time Optimization with no penalty (PSO-NP). The penalty being the generation of a higher than normal congestion ratio in non-failures scenario when the link weight set used in our network only targets the failure scenario. PSO-NP determines a suitable set of OSPF link weights at the start time that can handle any link failure scenario preventively while suppressing the penalty for the non-failure scenario. Previously, a preventive start time optimisation was presented to minimize the worst case congestion ratio in case of failure. That scheme unfortunately presents a non-negligible penalty when there is no link failure in the network because it only focuses on the failure scenario. In this paper we consider both the worst case failure scenario and the non-failure scenario.We suppress that penalty while enhancing the Preventive Start-Time scheme to counter failures. Simulation results show that PSO-NP achieves substantial congestion reduction for any failure case while eliminating the penalty in case of no failures in the network.