A study of waveband routing and wavelength assignment in multi-granular hybrid optical networks

Waveband routing and wavelength assignment (WRWA) has only recently attracted attention from the optical networking industry for its practical importance in reducing the control complexity and cost of optical cross-connects (OXCs). In this paper, we study WRWA tasks in hybrid hierarchical wavelength division multiplexing (WDM) networks with OXCs that can route multiple granularity (wavelengths and wavebands) at the same time. We develop a unique integer linear programming (ILP) model of a network with those OXCs with the objective to minimize the cost of optical-electronic-optical (OEO) and all optical (OOO) ports used. The optimal ILP solution can only be obtained for networks of smaller size. For larger problems we use a heuristic WRWA algorithm which was presented in our earlier work. Simulation results in this paper show near optimal performance of the heuristic WRWA algorithm for networks of smaller size.