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

This paper proposes a routing and wavelength assignment (RWA) scheme that supports multiple multi-carrier light source (MCLS) nodes to minimize the number of required wavelengths for wavelength-reusable multi-carrier-distributed (WRMD) mesh networks. There are two unique features in these networks. First, a light source, called the MCLS, is required, which eases the difficulty of controlling many light source devices. Second, optical carriers are reused to improve the efficiency of wavelength usage. For large-scale networks, there may be a need to have more than one MCLS node for using resources efficiently. To utilize wavelength resources efficiently, we formulate the RWA problem as an integer linear programming (ILP) problem to obtain the minimum number of required wavelengths to satisfy the given lightpath setup requests. Numerical results show that the ILP approach with two carrier regenerations for the WRMD network achieves the same numbers of wavelengths as the optimal ones. In addition, the suitable number of the MCLS nodes is shown to reduce the number of required wavelengths for lightpath establishment.