| In this research, we investigate several important and fundamental design issues in wavelength division multiplexing (WDM) networks, such as traffic routing, wavelength assignment, wavelength conversion and survivability. Using the solutions and studies presented in this research, different system metrics can be optimized or greatly improved for various scenarios, to achieve an efficient and flexible WDM optical network.; We first investigate the problem of routing and wavelength assignment (RWA) for assigning connections in a survivable WDM optical network. We have developed algorithms based on the static and dynamic strategy for establishing protection paths. The dynamic strategy allows for re-arrangement of protection paths, that is, both the route and wavelength chosen for the protection path of an existing connection can change so as to accommodate new connection requests. One of the results of our study is that contrary to intuition, the static strategy performs better than the dynamic strategy.; In our next research on optical network survivability, we propose a new survivability scheme called sub-path protection. We show that our proposed sub-path protection scheme is more efficient and flexible in providing failure recovery, and has advantages over the traditionally used link and path schemes. Further, the sub-path scheme can provide a good trade-off between capacity utilization and restoration times required for failure recovery. We study the effect of using wavelength conversion on various network parameters under static and dynamic traffic conditions. Our results indicate that the use of wavelength conversion can considerably reduce the blocking of the network under dynamic traffic conditions, but there is minimal difference in the wavelength requirements while building a green-field network using wavelength conversion.; We investigate the RWA problem for assigning connections profitably in optical networks. In this work we model the problem of profit maximization as a modified RWA problem and propose various solutions by which a carrier can maximize the profit for static and dynamic traffic. We also investigate the effect of lightpath re-arrangement on the profitability and extend this work to consider survivable optical networks consisting of multiple traffic classes, wherein each class of traffic may require a different amount of protection. |
