Research On SDN Multi-controller Structure Based On Traffic Scheduling Problem

With the development of large-scale network,people can get the rich experience from it.At the same time,the number of network services and bandwidth traffic increased dramatically.Traffic scheduling is an important skill to enhance the network efficiency and control ability.Traditional traffic scheduling has some inevitable problems in global coordination and flexibility and so on.SDN(Software Defined Networking)technology divides the network into three layers:application,control and data,which greatly improves the flexibility and scalability of the network.Traffic scheduling based on SDN can improve the bandwidth utilization rate by scheduling data flow reasonably to avoid congestion,and can also control the network traffic fine to adapt to the real-time changes of network traffic dynamically.Therefore,SDN traffic scheduling has a great significance to improve network performance.Based on the SDN traffic scheduling,in this paper,from the perspective of SDN multi-controller,the main work is as follows:(1)This paper studied the OpenFlow communication protocol in SDN in detail,and analyzed the SDN switches,multi-flow table structure and the process of data-forwarding in detail.The two methods of SDN traffic scheduling were studied from the perspective of load balancing.It was pointed out that the key problem of SDN traffic scheduling was to study the load balancing of multi-controller.(2)In this paper,the load balancing of multi-controller was studied deeply,the static load information was added to the dynamic load balancing,which lead to a distributed multi-controller load balancing-DLCA(Distribute Load-Balance Controller Architecture)architecture,which was consists with the top named load balancing system and the bottom named controller layer system.Each layer was also composed of many modules which had the various functions,and the specific implementation of the various modules were explored,so that this architecture could achieve multi-controller load balancing.(3)This paper combined the Raft election algorithm with the SDN multi-controller,which could select load balancers from multiple controllers in the DLCA architecture by the election algorithm.(4)The load balancing algorithm and the election algorithm in DLCA were simulated on Mininet in this paper.The simulation results showed that the load balancer system of DLCA architecture could maintain the load balancing of the controller layer,and when the load balancer failed or some controllers are overloaded,the election algorithm could select a new load balancer from the controllers to take over it,which could continue to maintain the system of traffic load balancing.