Multicast routing and wavelength assignment in multihop optical networks

This paper addresses multicast routing in circuit-switched multihop optical networks employing wavelength-division multiplexing. We consider a model in which multicast communication requests are made and released dynamically over time. A multicast connection is realized by constructing a multicast tree which distributes the message from the source node to all destination nodes such that the wavelengths used on each link and the receivers and transmitters used at each node are not used by existing circuits. We show that the problem of routing and wavelength assignment in this model is, in general, NP-complete. However, we also show that for any given multicast tree, the wavelength assignment problem can be solved in linear time.