Resources allocation and routing in WDM Metropolitan Networks

Metropolitan telecommunications networks is a recent network concept imported from the data communication world, which is gaining considerable importance in present/near future networks. The emerging of optical transport networks (OTN) which uses Wavelength division multiplexing (WDM), associated to the concept of all-optical networking is shaping the evolution scenarios for the Metropolitan networks. In spite of the similarities between existing WDM systems for long-distance and metro networks the cost functions are not the same for the two network segments. In metropolitan networks, cost is a major factor, which in spite of the technological advantages that all-optical networking can bring, is preventing its faster penetration. In this paper we present a possible solution to introduce WDM in this segment, based on the usage of less expensive asymmetric optical nodes, in which the handling of optical channels directed from the long distance network to the metropolitan and distribution networks is achieved by the analysis of the specificity of each case, the required functionality implemented having them into account and in most of the cases realised by one or two optical components, which reduces the cost. This approach requires a more detailed planning phase and has some implications in terms of resources allocation and wavelength routing in particular if end-to-end optical channel routing. These will be analysed in the proposed solution for the metropolitan network.