Research On Virtual Optical Network Embedding Algorithm For Dynamic Traffic In Elastic Optical Networks

In order to accommodate the future development trend of Internet and communications,elastic optical networks are proposed.In addition,as network infrastructures have become increasingly rigid,network virtualization technologies have been introduced.However,one of the problems to be solved to realize network virtualization is virtual optical network embedding,which is essentially a resource allocation problem,but the dynamic nature of the traffic and the multiple constraints that exist when virtual network embedding limit the way of resource allocation and reduce the efficiency of network resource utilization.Therefore,the thesis focuses on how to efficiently embed virtual optical networks to the substrate elastic optical networks.1.To solve the difficulties of long embedded optical path and excessive spectrum fragmentation when embedding virtual optical network,a cooperative virtual optical network embedding algorithm based on adjacency link fragmentation awareness(ALFACVONE)is proposed.Firstly,the node ordering rules are designed to achieve efficient node embedding,and the node-link cooperative embedding method is used to short the embedded optical path length to reduce the spectrum resource consumption.Secondly,the spectrum dispersion and the number of hops on the path are also considered in the path selection to improve the link embedding success probability.Finally,the fragmentation metric formula is designed to improve the utilization of spectrum resources by considering the fragmentation impact caused by the pre-allocated spectrum blocks on the currently selected paths as well as the neighboring links during spectrum selection.The simulation results show that the designed algorithm shortens the average embedding path length and also improves the spectrum utilization.2.To address the problem of low virtual network request acceptance ratio caused by the mismatch between the allocated resources and the required resources after the virtual network bandwidth resource demand change,a virtual optical network embedding algorithm of resource reconfiguration towards time-varying traffic(TVT-RRVONE)is proposed.Firstly,according to the resource attributes and topology attributes of nodes,the node weight measurement formula is designed to strengthen the correlation between node embedding and link embedding.Secondly,the metric formula of path spectrum resource abundance is designed to avoid the failure of link embedding due to insufficient path resources during spectrum allocation stage.Finally,in order to adapt to the dynamic change of time-varying traffic bandwidth requirements,resource reallocation to accommodate bandwidth fluctuation strategy and resource-aware virtual network reembedding strategy are proposed,respectively.The simulation results show that the designed algorithm can effectively improve the spectrum utilization and the virtual network request acceptance ratio.