Dynamic routing and wavelength assignment in all-optical networks

All-optical wavelength-division-multiplexed (WDM) networks using wavelength routing are believed to be potential candidates for the next generation of wide area backbone networks. One of main issues in such networks is the Routing and Wavelength Assignment (RWA) problem, which has been proved NP -complete. Many algorithms have been proposed in order to solve this problem efficiently, and several analytical models have been proposed to analyze the network performance. Basically, these analytical models can be separated into three categories, according to the assumptions they used. First is the wavelength decomposition model, which assumes the utilization of each wavelength on a link is independent to other wavelengths and other links. Second is the link decomposition model, which assumes the state of each link is independent to the other links. Recently, a new model called the path decomposition model has been proposed, which separates the network into several path systems and solves the Markov process of each path system. The wavelength decomposition model is the simplest model and can be used to study the quantitative behavior of the network since it does not require recursive calculation. The path decomposition model is the most accurate, but the complexity is very high. For large networks, approximation needs to be made in order to make the problem tractable. This will degrade the accuracy.; However, there are two issues that are rarely considered by current studies. The first one is the multicast routing problem, which is to setup connections between one source and multiple destinations. The main problem related with multicast is the duplicated information transmitted in the network, which will consume large amounts of bandwidth. The basic idea here is to route the multicast connections using a tree, which has the advantage of being able to minimize the duplicated information. The second issue is the traffic grooming problem, which is the multiplexing of multiple connections into one lightpath. In general, the bandwidth requirement of a call is much smaller than the bandwidth of a wavelength channel. If the calls are limited to be routed using single hop connections (one lightpath), the throughput of the network will be low because of the low utilization of the lightpaths.; In this thesis, we first study these two issues separately. Four schemes have been proposed for supporting multicast routing in a wavelength-routed network, and two algorithms have been proposed to solve the traffic grooming problem. Then the multicast traffic grooming problem is addressed, and three algorithms are proposed to support traffic grooming based on trees, tunnels, and subtrees respectively. Analytical models are proposed for these algorithm. The numerical results shows that our analytical model is quite accurate. In addition, with consideration of these two issues, our algorithms can achieve a great improvement in performance.