Research On Load Balancing In Control Plane Of SDN

In traditional large-scale networks,new business deployment,troubleshooting and network management need to deal with a lot of complicated configuration,which may result in problems such as slower business online and difficult application of new technologies.The emergence of SDN network architecture can greatly alleviate these problems.However,with the continuous expansion of the network scale,centralized control of the SDN may make the control plane a bottleneck of the entire system.In order to solve this problem,many researchers proposed the distributed SDN architecture.However,in practical applications,the load imbalance among multi-controller in the control plane of distributed SDN architecture will greatly affect the network performance and user experience.This paper proposes SHLB,a load balancing model uses in the control plane of SDN,which can effectively alleviate the load imbalance in the control plane and realize transparency between the control layer and the data layer by inserting an intermediate layer between control plane and data plane and applying flow classifier strategy in the middle layer.Firstly,this paper designs and implements a load balancing algorithm in the control plane,in which,the controllers are divided into a global controller and local controllers according to their different roles.The global controller is mainly responsible for load balancing in the control layer and dynamic expansion or reduction of the local controllers.The local controllers are divided into active controllers and dormant controllers.The active controllers mainly process flows from the middle layer.The dormant controllers only accept commands from the global controller for changing state.When a local controller is overloaded,the global controller will select a active controller or activate a dormant controller to balance the load and improve the network performance.For the data layer,the middle-layer shields the execution process of the control plane and avoids the migration of flows and flows table.Secondly,this paper designs and implements a scalable middle layer which can classify the flows.The classifier can classify flows from the data layer and forward them to different controllers.That is,different controllers handle different types of messages,which can effectively reduce the load of the control plane and reduce the migration frequency of the data plane.In the middle layer,the firstly deployed controller calls a master to handle the load problem of the middle layer and others call slave.When a slave is overloaded,the master select a light-load slave or start a new slave to solve heavy load in the middle layer,which avoiding the migration of flow and flow tables,and greatly improving the network performance.Finally,this paper tests the SHLB model,and the experimental results show that compared with the two-layer distributed SDN architecture,the SHLB can indeed alleviate the frequency in the overloaded control plane,thereby reducing the frequency of switch migration,reducing network delay and maintaining network performance stability,availability and scalability.