Online broadcasting and multicasting in WDM networks with shared light splitter bank

In this paper we deal with online broadcasting and multicasting in a WDM optical network with shared light splitter bank. Our objective is to maximize the network throughput. Since light splitting and wavelength conversion switching in WDM optical networks is cost expensive and fabrication difficult, we assume that only a fraction of network nodes are equipped with limited number of light splitting and/or wavelength conversion switches, and they are shared by all incoming and outgoing signals at each installed node. We first propose two cost models of realizing a broadcast or multicast request to model the consumption of network resources, particularly in modelling the light splitting and/or wavelength conversion resources consumption. We then show that under either of the two proposed cost models, finding a cost-optimal broadcast or multicast tree for a broadcast or multicast request is NP-complete, and instead devise approximation and heuristic algorithms for it. We finally conduct experiments to evaluate the performance of the proposed algorithms.