Research On Grooming Ports Configuration And Rerouting In WDM Networks

Networks have become increasingly popular in contemporary society.With the rapid development of Internet and multimedia business,demands for high bandwidth networks are increasing.The development of optical network technology offers the possibility for the high bandwidth.Grooming port is an important electrical switching device which can make a plurality of services be multiplexed to the same light path.It is the key factor to improve the wavelength utilities,reduce the blocking probability and improve the performance of WDM optical network.However,its high cost and high energy consumption determines that the grooming ports cannot be a lot of configuration in the network.In this thesis,under the premise of a limited number of grooming ports,the ports are legitimately allocated and traffic are groomed more reasonably by assessing the importance of network nodes,statically establishing light path and a series of other policies.Then the blocking probability is reduced and the performance of network is also inproved.Two allocation strategies to grooming ports based on the enhanced betweenness are proposed and their performances are simulated.Based on the enhanced betweenness,the static light paths are established between the primary nodes.So the traffic in the network can be together with the purposes.Meanwhile,under the non-uniform traffic the performance of network is further studied.The adverse effects of burst traffic on network can be effectively inhibited by a reasonable allocation of groorring ports and establishing static light paths.In dynamic WDM networks,connections arrive and departure randomly.The blocking probability in such network with the wavelength continuity constraint is relatively high.Rerouting can rationalize the light paths and make them adapt to the current network environment better.So the network blocking can be alleviated.However,the rerouting mechanism can lead to interruption of the transmission which affects the transmission quality.The excessive number of rerouting is not good for the network.The traditional passive and active rerouting algorithms are analyzed in the thesis first.And then,in the stage of wavelength allocation based on the active rerouting algorithm,the strategy of wavelength selection is improved so than the number of rerouting can be reduced obviously.On the basis of the reserve wavelength channel wavelength rerouting(RWC_WR)algorithm,a new rerouting algorithm is proposed with considering the importance of nodes.It can reduce the blocking probability so as the number of rerouting in the networks.Finally,the load-balanced active rerouting algorithm is proposed.The load of each link is measured by the wavelength usage of the link.The traffic of each link is legitimately adjusted to reach load balance by rerouting so as to achieve the effect of reducing the blocking probability.The common auxiliary graph model and the simulation parameters the algorithms used are presented in this thesis.Combined with auxiliary graph model and traffic grooming policy in WDM networks,all the algorithms proposed in this thesis are simulated by the OPNET network simulation tool.Finally the reliable data is got to verify the effectiveness of the algorithms.