ADAPTIVE WEIGHT FUNCTION BASED ON ENHANCEDLEAST RESISTANCE FOR ROUTING ALGORITHMSIN OPTICAL WDM NETWORKS

摘要

The main objective of this research paper is to enhancethe efficiency of routing and wavelength assignment(RWA) for optical Wavelength Division Multiplexing(WDM) networks. Normally, the transport protocol inWDM networks is based on connection-orientedtransmission that in physical it uses circuit-switchingtechnique. Therefore, when a session request is given, thehard task of routing and wavelength assignment is how todetermine the satisfied path between two nodes, and alsoto assign an available set of wavelengths along this path.To overcome these problems, we have proposed a newapproach, called Enhanced Least Resistance (ELR)algorithm, in order to achieve the effective routing andwavelength assignment that can find the least resistantlightpath for user’s requirement. The link weight functionis considered as the main important factor for routeselection in ELR algorithm. And this function iscalculated by using a determination factor of the numberof wavelengths that are being used currently and aresupposed to be available after a certain time. In accordingto ELR algorithm, the session requests from users will berouted on the links that has the least number of linkweights by using Dijkstra’s shortest path algorithm. Thismeans that the selected lightpath will have the leastresistance, i.e., low blocking probability. Theperformance ELR is investigated by using Abilenenetwork as a simulation model. The simulation resultsshow that the proposed ELR algorithm can achieve betterperformance in terms of the blocking probability whencomparing with the well-known traditional mechanism.