Routing Algorithms In WDM Optical Networks

All-optical networks employing the concept of WDM and routing and wavelength assignment (RWA) are considered as the most competitive transport networks for the future. RWA is an important problem in WDM networks. Given a call or lightpath to be established between a node pair, the problem is to find a route from the source node to the destination node and assign a wavelength to this route. A study is made of the routing subproblem in this paper, and the algorithm is evaluated in simulations by the mathematical software Matlab.The existing RWA algorithms are summarized firstly, so are the basis and realization of the simulation of the algorithm. By extending the conventional method called least loaded routing (LLR), two alternate routings named least loaded-hop routing (LLHR) and least load-sum routing (LLSR) are proposed, which take both link load and route hop count into account. Simulation results show that the algorithms can significantly reduce blocking probability and improve network performance compared with LLR. Another priority-based alternate routing algorithm is also presented in this paper. Compared with the existing algorithms based on priority, the routing problem is paid more attention to in this algorithm, with restoration of networks enhanced. Simulation results show that the algorithm can effectively reduce blocking probability of requests with different priorities.