Research On Reliability Of SDN Multi-controller Based On Hardware Software Cooperation

In recent years,with the rapid development of the Internet,the traditional network has been unable to control the increasingly complex network structure and increasing data traffic.In order to adapt to the development and progress of network,a new network architecture was born,which is named software defined network(SDN).This network architecture separates the control layer from the data layer in the traditional network,and the control layer implements centralized control.Because SDN can improve the programmability of the network and realize the flexible control of network traffic,it has aroused widespread concern in the academic community.One of the key research topics is how to improve the reliability of SDN network.The research models of SDN network reliability are mainly divided into single controller and multi controller.Single controller often meets performance bottleneck in large-scale SDN network.For example,when the controller load is large,single controller usually miss the transmission request of switch,which may cause data accumulation or network paralysis.In order to solve this problem,researchers propose to use multiple controllers to realize the distributed structure of the logical centralized SDN network.This multi controller SDN structure can deal with the fault of single controller and improve the service reliability of SDN network.On this basis,in order to study the reliability of multi controller SDN,the main innovations of this paper are summarized as the following three points:(1)Because most of the research on SDN reliability is based on software implementation,in order to improve the efficiency of the algorithm,this paper designs a SDN multi controller model based on software and hardware cooperation,which uses VC709 evaluation board as a dynamic resource cooperation platform to accelerate the algorithm.(2)Aiming at the problem of controller failure in multi controller SDN network,in order to maintain the network connectivity,this paper proposes a SDN multi controller fault recovery algorithm based on hardware and software cooperation.The algorithm considers the delay between the switch and the controller,the switch failure rate and the switch throughput.The algorithm selects the successor controller of the fault controller based on the improved random forest algorithm(MRF).It ensure that the control layer can still control the data layer and release the data forwarding task in time after the fault recovery.The experimental results show that the algorithm can reallocate the switches in the fault controller domain.Moreover,the completion speed of the algorithm on the dynamic resource collaboration platform is two orders of magnitude higher than the software platform.(3)Aiming at the problem of node failure caused by switch failure in SDN network,this paper proposes a SDN switch failure recovery algorithm based on hardware and software cooperation by combining network protection and network recovery mechanism.The algorithm uses the shortest path algorithm on the basis of the separation path algorithm,which can not only solve the switch fault problem more flexibly and quickly,but also consume less memory resources.The experimental results show that the algorithm can ensure the reliability of nodes and the effectiveness of the shortest path.