A heuristic method of logical topology design in WDM optical networks

This paper introduces a heuristic approach as a solution to the problem of routing, wavelength assignment (RWA), and traffic grooming when designing a logical topology given the network physical topology. The RWA problem is known to be the assigning of network resources (wavelengths, transmitters, and receivers) to successfully establish lightpaths in the wavelength division multiplexing (WDM) optical network. The traffic grooming problem is the multiplexing of lower speed connection requests to high speed streams. The physical topology consists of nodes and fiber links connecting these nodes. The logical topology consists of same nodes and lightpaths between these nodes, where a lightpath represents a direct optical connection without any intermediate electronics. For a given network physical topology and traffic pattern (traffic distribution between every node pairs), the objective is to design a logical topology and a routing algorithm so as to minimize both the average packet hop distance and amount of processing at each node. Two constraints are considered, namely, the number of wavelengths required to embed the resulting logical topology and the number of transmitters and receivers per node.