PLANNING METHOD OF ROBUST WDM NETWORKS AGAINST TRAFFIC CHANGES

Many researches have been investigated on planning and/or designing WDM networks, but most of them assume that the future traffic demand is known be-forehand. However, it is difficult to predict the future traffic demand accurately in a practical sense since there are various types of data traffic with different traf-fic characteristics. More flexible planning/design methods are necessary to ac-commodate the unpredicted traffic demand. In this paper, we develop a scheme to design a WDM network that would accommodate as much traffic as possible against a variety of traffic patterns, that is, a WDM network robust against traf-fic uncertainties. We resolve such a problem by incrementally installing OXCs and fibers until they reach a condition that a robust WDM network needs to ful-fill. Our approach for designing such a network is divided into two problems; the OXC–deployment problem and the fiber–deployment problem. In both prob-lems, our basic idea is to select a node–pair that is expected to be a bottleneck in the future, and then to deploy network equipments so that the volume of traffi