Research On Optimization Of Routing Algorithm In SDN Architecture

With the development of network,people's demand for network performance is higher and higher,and the demand for network bandwidth and other resources is also increasing rapidly.However,the existing network devices are complex and diverse,and the traditional network structure is rigid and difficult to manage.The emergence of the software defined network brings dawn to the network administrator.The software definition network makes the network software.The architecture is free from the restriction of the hardware to the network.It has the advantages of flexibility and programmable,so it is convenient to manage and modify the network.A logical centralized controller with a global network view in a software defined network is responsible for all control decisions and communicates with a distributed forwarding unit through a standardized interface.In this paper,two optimization schemes are proposed for traffic scheduling in SDN.One is to optimize the disassembled traffic in the network,which includes the optimization of the model and the improvement of the existing algorithms;one is to provide a better network path for the undisassembled traffic in the existing network.The main research work of the thesis is as follows:(1)For the problem that the TCAM(Ternary Content Addressable Memory)resource of the flow table is limited when the detachable traffic is transmitted in the network,a multicommodity flow model is established by limiting the number of paths passed by the path node,eventually achieving the purpose of fine-grained control of the flow and reducing the flow table resource excess consumption.The model minimizes the maximum link utilization as the optimization goal.After adding the restriction of the number of node paths,the network traffic can be balanced and the flow splitting can be effectively controlled,saving the TCAM resources of the flow table.Finally,through the solution,the validity of the model is proved.(2)In order to utilize the link resources in the network more effectively and improve the existing Dijkstra node potential multi hop routing algorithm(NPMA-Dijkstra),an optimized multi hop routing algorithm(MNPMA-Dijkstra)is proposed to solve the problem of network topology.Simulation experiments show that the algorithm is effective in terms of the number of paths and the proportion of traffic.(3)Based on the flexible and controllable characteristics of SDN,a routing scheme that satisfies the Qo S constraint path is designed according to the flexible and controllable characteristics of the current network.This strategy uses the SDN architecture to control the global information of the network,uses the minimum cost as the optimization goal of the network,evaluates the link cost according to the traffic service type,and uses the Lagrange relaxation algorithm to solve the problem.Verify the feasibility of the solution in the final simulation environment.