Research On Routing Spectrum Allocation Algorithm And Optimization Strategy In Elastic Optical Networks

With the rapid development of various bandwidth hungry services such as cloud computing,live webcasting and high-definition multimedia,traditional Wavelength Division Multiplexing(WDM)optical networks are facing difficult to meet the today's high-speed network service requirements due to its fixed grids resource allocation features.Elastic optical network(EON)adopts orthogonal frequency division multiplexing(OFDM)technology,which can provide high bandwidth utilization and on-demand resource allocation characteristics simultaneously.How to utilize spectrum resource efficiently and decrease energy consumption has been an ugent issue with the rapid growth of Internet traffic.This thesis presents a comprehensive and in-depth research on routing spectrum allocation problems and optimization strategy in EONs via theoretical analysis and experimental simulation.Firstly,this thesis introduces some fundamental concepts,system architectures,and key issues of elastic optical networks,along with the discussion of the existing routing and spectrum allocation(RSA)algorithms in elastic optical networks detailed,respectively.Aiming at the spectrum fragmentation and energy consumption in EON,a multi-domain awared energy-efficient routing algorithm is proposed.By adopting the fragmentation metrics both in spectrum domain and the spatial domain,the blocking rate of new services will be reduced.The newly arrived services are sorted to the already working links to reduce the number of newly built optical path and the working network components.The continuous working time of the path selects routes with shorter working hours to achieve energy saving.Simulation results show that compared with the traditional energy-saving algorithm,the proposed algorithm can effectively reduce the bandwidth blocking rate of the service and save network energy consumption,respectively.Finally,this thesis proposes an improved spectrum allocation scheme for EON based on spectrum candidate windows.The available spectrum candidate windows are searched for the arriving services,and the spectrum allocation is performed after screening for the idle spectrum block continuity.Theoretical analysis and simulation results show that the algorithm can greatly improve the continuity of spectrum resource occupation,thereby reducing spectrum fragmentation in the network and reducing the network bandwidth blocking rate.