Research On Load Balancing Of Controller Cluster For SDN

Based on the evolution process from software-defined network single controller to controller cluster,this paper studies the consistency,security and performance improvement of software-defined network from two directions of software-defined network control plane and data plane.Aiming at the traffic congestion and link delay,packet loss rate,bandwidth and quality of service requirements of software-defined network,a load balancing mechanism is designed systematically.At the same time,a corresponding system model is proposed to solve the bottleneck problems of fault tolerance of centralized controller and balancing of distributed controller.The main contributions of this paper are as follows:Firstly,aiming at the problems of balance failure and prolonged installation time of flow meter in the synchronous regulation mechanism of control plane load balancing.In this paper,firstly,a load balancing asynchronous regulation model of distributed controllers is established.Connected information of switches perceived by connected tables is used to regularly count traffic and monitor network load status.Secondly,an asynchronous tuning algorithm(DFPA,Digging and Filling Pit algorithm)is proposed,which takes into account the maximum transmission acceleration ratio and load capacity.A revenue function is introduced to measure the throughput and load capacity of idle controllers.The overload flow of controllers is distributed asynchronously to the idle controllers with the greatest benefits on demand.It can improve the load imbalance of the network and quickly restore the normal load state of the network.By introducing multi-overload controller adaptation model,network consistency is enhanced and system overhead is reduced.The experimental results show that the load balancing asynchronous adjustment algorithm plays a good role in load balancing and adapts to load balancing dynamic adjustment of different traffic.Secondly,it aims at the requirement of specified traffic level on data plane and the problem of uneven load on control plane.In this paper,firstly,a load balancing model based on traffic priority is proposed to collect real-time information such as network link delay,bandwidth and so on.Traffic level identification module determines traffic priority.Secondly,an algorithm to find the minimum cost link is proposed.If there is a congested link,exclude it.Routing decision module uses Lagrange relaxation technology to find the minimum cost link.The simulation results show that the SDN distributed controller load balancing model based on traffic priority can meet the requirements of quality of service and play a load balancing role.