Routing And Spectrum Allocation For Multicast Over Elastic Optical Networks

According to a variety of emerging high bandwidth of multicast services,the current optical networks provided with the limited spectrum resource are undergoing the serious shortage of optical resources.We mainly deal with this problem from two perspectives of optimizing the optical network architecture and improving the spectrum resource utilization.Due to that the network coding technology has the advantages of improving the network throughput,robustness and balancing the network load,the network coding based multicast capable elastic optical network is proposed by integrating the network coding technology and all-optical multicast into elastic optical network.This paper mainly investigate hybrid services efficient provisioning problem over the network coding enabled elastic optical network in a reliable and efficient way.The contributions of this doctoral dissertation are summarized as followings:(1)The research on multipath routing and spectrum allocation over the network coding enabled elastic optical networks.We proposed a multipath routing and spectrum allocation algorithm,considering the time delay constraint to ensure the real time transmission for multicast service.A layered graph approach is utilized in the proposed algoirhtm,and the routing and spectrum allocation is sloved in an integrated way.From the simulation results,compared with the benchmark algorithms,as different simulation parameters change,the proposed algorithm NCMC-MRSA utilizing the ordering policy of SRB(Spectrum Request Balancing)shows the best spectrum utlilization in most test networks.With the increase of the average number of multicast receivers or the random network size,the proposed NCMC-MRSA outperforms the MC-RSA with 21.63%improvement of spectrum utilization,and the improvement is more obvious in the large-scale network.In addition,the impact of different requests ordering policies on the performance of the proposed algorithm is also evaluated.(2)The research on the hybrid services efficient provisioning over the network coding enabled multicast capable elastic optical networks.Considering the existence of different types of services,the hybrid services efficient provisioning problem is investigated over the network coding enabled multicast capable elastic optical networks.A mathematic model is proposed with the constraints of time delay and maximal transmission distance,and a network coding enabled adaptive routing and the layered graph approach based spectrum allocation is proposed.The proposed algorithm could adaptively select different routing policies for different types of services.The simulation results show that as the average number of multicast receivers or the random network size increases,the proposed NCAR-LGSA algorithm improves the spectral efficiency by 21.72%compar~ed with other benchmark algorithms in most random networks.With different routing mechanisms,the spectrum utilization of NCAR-LGSA outperforms the benchmark algorithms with the average increase of 23.53%.Moreover,the performance advantage of NCAR-LGSA is more obvious in the real network.In addition,the impact of the number of parallel transmission paths on the performance of the algorithm is evaluated.(3)Research on reliable routing and spectrum allocation for hybrid services over network coding enabled multicast capable elastic optical networks.We mainly solve the problem of how to ensure the reliable routing and spectrum allocation for hybrid service requests in case of the failure occurs in the optical networks.An optimization mathematical model is proposed,and an efficient heuristic algorithm of reliable multipath routing and spectrum allocation algorithm for network coding based multicast is proposed.The proposed algorithm establishes an independent backup protection route adaptively for every working routing structure.In addition,network coding has the natural advantages of the information encryption,and improving the reliability transmission.From the simulation results,as different parameters change,the spectrum utilization can be improved by the proposed algorithm,compared with the benchmark algorithms.