Abstract: “This problem of traffic grooming, routing, and wavelength assignment (GRWA) is considered with the objective of minimizing the number of transponders in the network. We first formulate the GRWA problem as an integer linear programming (ILP) problem. Unfortunately, the resulting ILP problem is usually very hard to solve computationally, in particular for large networks. To overcome this difficulty, a decomposition method is proposed that divides the GRWA problem into two smaller problems: the traffic grooming and routing (GR) problem and the wavelength assignment (WA) problem. In the GR problem, we only consider how to groom and route traffic demands onto light paths and ignore the issue of how to assign specific wavelengths to light paths. Similar to the GRWA problem, we can formulate the GR problem as an ILP problem. The size of the GR ILP problem is much smaller than its corresponding GRWA ILP problem. Once we solve the GR problem, we can then consider the WA problem, in which our go”

Keywords: ILP: integer linear programming, RWA: Routing and Wavelength Assignment, GRWA: grooming, routing, and wavelength assignment, GR: grooming and routing, FTPS: Fault Tolerant Path Set, NSF: National Science Foundation Standard network model.