Research On Network Virtualization In FlexGrid Optical Networks

In recent years,with the rapid growth of Internet services,the network structure is becoming more and more complex,and the demand for network bandwidth is growing at the speed of Moore's law.The emergence of various Internet services and technologies has led traditional optical networks unable to meet the needs of flexible allocation and management of spectrum resources.In contrast,flexible grid optical networks,which can flexibly allocate spectrum resources based on the demand of services,will surely play an important role in the future optical transport network.At the same time,the network virtualization technology.It studies how to abstract the underlying physical resources and allocate network resources,by design of virtual mapping algorithm,for client networks(virtual networks).For different physical networks,the allocation scheme is different.How to map virtual subnet quickly and effectively with a lower blocking rate of virtual network requests is a key issue to consider for the virtual mapping algorithm.In a flexible grid optical network,if the communication resources of the data center can be utilized in the virtualized resource allocation process,the underlying optical network spectrum resources can be effectively saved,thereby reducing the service request block rate.Therefore,this paper proposes a node aggregation mapping algorithm for this situation.The algorithm enables the virtual network request to map different virtual nodes to one physical node during the mapping process,and the bandwidth requirement between the aggregated virtual nodes is provided by the corresponding data center.The paper also studies the problem of spectrum fragmentation caused by dynamic allocation of virtual networks,and proposes a spectrum fragment cascade mapping algorithm,which aims to reduce the traffic blocking rate and improve the resource utilization to some extent.For the flexgrid optical network with typical network topology,the node aggregation algorithms proposed are compared with non-node aggregation algorithms.Simulation results show that the node-aggregation mapping algorithm can reduce the blocking rate of virtual requests when applied to different flexible grid optical networks with various classical topologies and has a good load balance.cascading mapping algorithm show that the fragment cascading can alleviate the problem of fragmentation of spectrum resources,and improve the utilization of spectrum resources to a certain extent and reduce the blocking rate of virtual requests.