Research On Elastic Optical Multicast Switching Node Architecture And Scheduling Algorithm Based On FDL And ROADM

Emerging Internet applications,such as cloud computing,high-definition media streaming,remote applications,are attracting users' attention while needing more network capacity,transmission quality and transmission rate.Multicast technology can provide good support for these applications.Multicast technology can achieve transparent transmission with high speed,high bandwidth capacity and good robustness.However,the rapid increase of requests aggravates the burden of switching node.Optical multicast contentions occur more frequently for the replication and forwarding of the optical multicast in the node.The contentions lead to the poor node throughput.At the same time,with the increasing of multicast requests and optical layer equipment in the all-optical colorless,directionless,contentionless and flexible ROADM elastic optical switching network,the energy consumption of the network further increase.Hence,it is important to design better scheduling algorithm to improve the throughput of the optical switching node.In addition,it is necessary to promote the all-optical network energy efficiency while ensuring the successful transmission of the requests.Therefore,we do some research to improve the performance of node and the whole network from two aspects.Firstly,from the perspective of improving the node throughput,in chapter 3,a new optical node architecture integrating with output shared all-optical Orthogonal Frequency Division Multiplexing(OFDM)network coding technology and shared feedback fiber delay lines(FDLs)buffer is designed.The multicast function is realized by configuring the optical splitter in the elastic optical switching node.The contending requests are addressed by the shared feedback FDLs in time domain and the output shared all-optical OFDM network coding in spectrum domain.In order to further improve the throughput of node,a time-frequency joint scheduling strategy(TFJSS)is proposed.In TFJSS,the maximal weighted independent set algorithm is used to select the output packets with no overlapping spectrum among the contending multicast requests.The remaining contention requests are coded by OFDM network coding with all-optical XOR operation in spectrum domain.If the network coding cannot successfully resolve the contending requests,the shared feedback FDLs are called to address the contention in time domain.Compared with the existing node architectureand scheduling algorithm,the simulation results show that the proposed node architecture and scheduling algorithm in this chapter can reduce the node blocking rate with low delay largely and improve the performance of switching node to solve the contention.Secondly,from the perspective of improving the whole network performance,in chapter 4,an energy efficiency scheduling algorithm is proposed in the CDC-F ROADM elastic optical multicast switching node based on the high spectral resolution processors.In routing phase of the scheduling algorithm,a minimum-cost path tree algorithm is designed to construct the multicast light tree.Firstly,a cost function is designed to compute a minimum-cost path for the source node to a certain destination node,which considers the impact of energy consumption and link resource usage on the network.The path is added to the light tree,and then the destination node is deleted.Secondly,the minimal-cost path is calculated for the remainder destination node to the existing light tree,and the minimal-cost path is added to the light tree,and then the destination node is deleted in turn.Finally,the minimal-cost tree is used as the routing path.In resource scheduling phase,firstly,the spectrum resources usage of all links in the light tree is calculated.When there are available spectrum resources to satisfy the requests transmission in the links,but the spectrum resources do not satisfy the spectrum consistency constraint,the requests can be spectral converted by the corresponding node.And then the spectrum resources are allocated for the requests.The simulation results show that the proposed algorithm can effectively promote network energy efficiency and reduce the bandwidth blocking rate.