The Study Of The Scalability Problem For Software Defined Networks

With the "Internet +" gradually into every aspect of people’s lives,the problems exposed by the Internet getting more serious,such as energy efficiency,security,and scalability.Among them,there is a network architecture focused on reform of the network,it has become a landmark of the new network architecture.It is software defined network.SDN network device control and data planes separated,enabling flexible control of network traffic,making the network to become more intelligent.The scalability problem for SDN has been a hot and difficult research field.Existing studies have focused on improving the performance of a single point of control,but expanding the network size,the amount of data increases,and the limited processing power of a single controller,which is bound to encounter bottleneck.So researchers began to deploy larger SDN network through distributed control plane design.This article discusses in a large SDN network,by increasing the number of controllers to solve SDN control plane scalability problem.The main work and include:(1)For information interactive mode between controllers and switches in SDN network,establishing a communication model.We made the captain,the waiting time and the number of controllers to the elments of the optimization objective function.Through genetic algorithm,we obtained the optimal number of controllers.(2)We proposed a highly reliable and load balance supported domain division algorithm for software defined,and determined the positions of controllers.Then this paper compared this algorithm with k-means algorithm on load balancing,network reliability and propagation delay performance.(3)Designed and deployed of Ryu controller and mininet simulation platform for SDN network.We used them to verify the feasibility of the algorithm.For SDN network scalability problem,the algorithm of this paper can effectively solve the problem of the control domain division,when the network is increasing the number of controllers need to be extended.Its main advantages are:(1)In consideration of the load capacity of the controller is limited,so to achieve load balancing control domain;(2)to enhance the connectivity of the domain,which is to improve the reliability of the network.