Disaster-Resilient Routing Schemes for Regional Failures

Abstract

Large scale natural disasters can have a profound effect on the telecommunication services in the affected geographical area. Hence, it is important to develop routing approaches that may help in circumventing damaged regional areas of a network. This prompted the development of geographically diverse routing schemes and also of disaster-risk aware routing schemes. A minimum-cost geodiverse routing, where a minimum geographical distance value D is imposed between any intermediate element of one path and any element of the other path is presented. Next the problem of the calculation of a D-geodiverse routing solution which ensures a certain level of availability is tackled. An algorithm is described that either obtains a solution to that problem or the most available path pair satisfying the desired geographical distance value D - this can be useful for the specification of availability levels in Service Level Agreements. Finally, a case study is presented, in an optical network, to determine the cost increase in terminal equipment (transponders) of approaches to ensure a much larger separation of the paths (of the selected path pair), with respect to minimal length link-disjoint routing.