Research On Optimization Of SDN-Based Load Balancing

With the development of cloud computing,big data and Internet of Things,increasing demand for the network,people need to speed up innovation of network technology urgently.The biggest difference between Software Defined Network(SDN)and Traditional Network is that SDN can control the network forwarding by programming and separate the forwarding plane from the control plane in network.Simultaneously,SDN can solve complex problems in traditional network in order to achieve global optimization using centralized control.So,this paper will optimize the controller and link load balancing algorithms based on the these characteristics of SDN.Firstly,the paper introduces briefly the basic concepts of SDN technology and common load balancing technology,and analyse the advantages and disadvantages of existing load balancing technology.Secondly,a controller load balancing method based on hierarchical architecture is proposed in this paper.When load of switch cluster which is managed by controllers exceeds the threshold,this paper presented a criterion for measuring the load of the controller,by migrating some switches to these controllers with lower load,it can realize load balancing of controllers.In addition,The method improves the existing switch migration algorithm effectively by optimizing inbound area,outbound area and selection of switches which will be migrated,migrating multiple switches at one time so as to avoid load shock and reduce time.And then,for link load balancing,an improved method based on Dijkstra algorithm is also proposed in this paper.By utilizing the characters of SDN network link which can collect link states,this paper drafted an assessment plan so as to get links status.If there is a link that is often blocked in the network,it will be deleted in our algorithm and we will recalculate k shortest path.Controller will decide to use which path by making load balancing strategy in order to achieve load balancing.Finally,the simulation experiment is based on Ubuntu virtual machine and Mininet simulation software,and then,compared the network load conditions,response delay,packet loss ratio and other factors.The simulation result indicates that the proposed algorithm can effectively balance the link load and the controller load,improve the network stability and reduce the network transmission delay.