Impairment -Aware Static Route and Wavelength Assignment in WDM Networks

Routing and Wavelength Assignment (RWA) is a fundamentally important aspect of WDM optical network design. RWA is performed to determine a route and wavelength for each demand requesting resources between a given source and destination node. Classic RWA has only been concerned with determining a route while only taking into account network layer wavelength availability constraints. In recent years the size of WDM optical communication networks has exponentially increased in size. Resulting in the use of very long fibers for interconnecting nodes. On these modern WDM networks, researchers have identified at the physical layer, linear and non-linear impairments. Impairment occurs during the propagation of optical signals across a fiber cable and within the optical switching fabric of routing equipment. These impairments have the potential to either, greatly reduce the efficiency of WDM optical networks, or to completely render lightpaths unusable. Impairment-aware routing and wavelength assignment (IA-RWA) takes different types of impairments of lightpaths into account, while performing the RWA. The use of IA-RWA improves the quality of transmission among lightpaths as well as reduce the blocking ratio. A new heuristic for IA-RWA has been reported in this thesis for use in WDM optical network planning and design. This heuristic takes both linear and non-linear impairments into account during the RWA process. The heuristic uses existing techniques from graph theory, operations research, and optical network design, to determine an IA-RWA in an efficient manner.