Slotted WDM, which achieves higher capacity compared with conventional WDM and SDH networks, has been discussed a lot recently. The ring network for this architecture has been demonstrated experimentally. In slotted WDM ring network, each node is equipped with a wavelength-tunable transmitter and a fixed receiver and assigned with a specific wavelength. A node can send data to every other node by tuning wavelength accordingly in a time slot. One of the important issues for it is scheduling. Scheduling of it can be reduced to input queued switch when synchronization and propagation are solved and many schemes have been proposed to solve these two issues. However, it’s proved that scheduling of such a network taking both jitter and throughput into consideration is NP hard. Greedy algorithm has been proposed to solve it before. The main contribution of this paper lies in a novel genetic algorithm to obtain optimal or near optimal value of this specific NP hard problem. We devise problem specific chromosome codes, fitness function, crossover and mutation operations. Experimental results show that our GA provides better performances in terms of throughput and jitter than a greedy heuristic.
Open Shortest Path First (OSPF) protocol is used for the routing and topology discovery in the optical networks. In the next generation optical network, enhanced OSPF is extended to support opaque LSA. In optical networks, each OXC disseminates the resource information of the optical links that bundled between the adjacent neighbors. Recently proposed enhanced OSPF protocol is promising to reduce the blocking probability of the data plane at the cost the usage of the control channel bandwidth in the control plane. This article has a full analysis of the bandwidth usage due to the optical LSA updates. We also discuss the blocking probability with the enhanced OSPF, some key results on the performance of the enhance OSPF are also given in this article. Finally, we propose a method to balance the tradeoff of the flooding information and the blocking probability.