This paper proposes a new dynamic-alternate routing algorithm and its corresponding converter placement algorithm in order to reduce the connection blocking probability for all-optical WDM networks. The main idea in the proposed dynamic-alternate routing algorithm is to try to route the traffics according to a predefined optimal probability distribution. The problem for finding the optimal probability distribution was shown as a convex optimization problem. The problem can be solved by flow deviation method or other standard optimization techniques. Simulation results show that the proposed routing algorithm yields lower connection blocking probabilities than the previous works. The proposed routing algorithm produces similar traffic pattern as the optimal traffic pattern. The similarity between the traffic pattern produced by the proposed dynamic-alternate routing algorithm and the optimal traffic pattern can be further employed for solving other network designing problems such as converter placement problem. Since the optimal traffic pattern can be easily predicted, the optimal traffic pattern which minimizes the blocked traffic intensity is utilized for finding the locations of wavelength converters. The key idea is to place the wavelength converters at the nodes where they are needed most. Simulations have been performed to study the performance of the proposed wavelength converter placement method. The simulation results have shown that the proposed placement method combined with the proposed probability based dynamic-alternate routing algorithm yields smaller connection blocking probability than the two converter placement methods with their corresponding alternate routing algorithms.
