Optimal placement of light splitters and wavelength converters for multicast in WDM networks

In wavelength-division multiplexing (WDM) optical networks, sparse light splitting and sparse wavelength conversion can achieve most benefit of full splitting and full wavelength conversion, provided that the light splitters and wavelength converters are properly placed. We propose an integer linear programming model for the optimal solution of the combined problem of light splitter placement and wavelength converter placement, in the sense that the total number of wavelength channels required by multicast requests is minimized. Solving the ILP model supplies the optimal placement of light splitters and wavelength converters, as well as the routing and wavelength assignment (RWA) approach under the presented sparse splitting and sparse wavelength conversion placement. The model can be applied to any optical network topology with any multicast traffic configuration, and can be used to get performance benchmarks when dealing with optical multicast under wavelength continuity constraint and multicast capability constraint.