A routing and wavelength assignment scheme supporting multiple light-source nodes in multi-carrier-distributed optical mesh networks with wavelength reuse

This paper proposes a routing and wavelength assignment (RWA) scheme that supports multiple light-source nodes to minimize the number of required wavelengths for wavelength-reusable multi-carrier-distributed (WRMD) mesh networks. These networks use a light source, called the multi-carrier light source (MCLS), to ease the difficulty of controlling many light source devices. Moreover, they are able to reuse optical carriers for improving the effectiveness of wavelength usage. Since the WRMD network suffers constraints different from those of the conventional wavelength division multiplexing (WDM) network, an RWA scheme for the WRMD network with a single light source was recently developed. To use the resources of large-scale networks efficiently, there may be a need to have more than one MCLS node. In this paper, we first formulate the RWA problem as the integer linear programming (ILP) problem of obtaining the minimum number of required wavelengths to satisfy the given lightpath setup requests. A heuristic RWA scheme is then introduced to solve the RWA problem in practical times. Simulation results show that the proposed heuristic RWA scheme for the WRMD network achieves a near-optimum number of wavelengths. In addition, optimizing MCLS node location is shown to reduce the number of required wavelengths for lightpath establishment.