We address the problem of multicast routing and wavelength assignment (MClowbarRWA) in wavelength-routed WDM optical networks. Multicast requests are facilitated in WDM networks by setting up so-called light trees and assigning wavelengths to them. Objectives of the MClowbarRWA problem include minimizing the number of distinct wavelengths used to establish a set of multicast requests and minimizing the cost of the corresponding light trees. This cost can represent the physical length, delay, or actual cost of a tree. Applications that require quality of service (QoS) multicasting can impose additional constraints on light trees, such as a bounded end-to-end delay. Proposed are heuristic algorithms based on bin packing methods for the general MClowbarRWA problem, which is NP complete. These algorithms can consider unicast, multicast, and broadcast requests with or without QoS demands. Computational tests indicate that these algorithms are efficient, particularly for dense networks.
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