Optimal allocation of limited optical-layer resources in WDM networks under static traffic demand

In this paper, four heuristic algorithms for the optimal allocation of limited optical-layer, resources in WDM networks (virtual-topology optimization by routing and wavelength assignment) under static traffic demand are compared. While some previous papers assumed that all connection requests must be necessarily satisfied, in this work algorithms are studied aiming at comparing their ability in minimizing both the usage of optical-layer resources and the number of connection requests that cannot be allocated. Thus, this paper reports the results obtained on a 13-nodes simplified topology of the pan-European optical transport network designed in the COST 239 Project. The results of a few hundreds simulations with different traffic matrices have been gathered, by considering separately the cost of resources allocated and the percentage of rejected connections. One algorithm resulted best performing, because in most tests it allocated the lowest cost of optical-layer resources. On the other hand, the four algorithms exhibited comparable performance with respect to the percentage of rejected connections.