Research On SDN Controller For Complex Space-Earth Integration Network

The space-earth integration network consists of space-based network,air-based network and ground-based network.The research of the space-earth integrated network has played a very important role in civil use,military affairs,and space exploration of a country.However,the air-space network has some problems such as frequent link switching,constrained resource,heterogeneous network protocols and topological variability,which makes it difficult for space-earth network to control and bring more challenges of scalability,compatibility,and reliability to the network.The software-defined network(SDN)has the advantages of decoupling the control plane from the data plane,providing an open programming interface,and a centralized control way,so that network devices can be managed flexibly and configured efficiently in a heterogeneous network environment.This paper combines SDN's multiple layered with multi-layer space-air network.Based on the characteristics of the space-air network and the SDN technology,the space-earth SDN network architecture was researched,and on the basis of this architecture,a distributed controller system was learned.The network architecture achieves flexible deployment and improves network' scalability and resource utilization,and makes space-earth more manageable.The main work and innovation of this paper includes:(1)Based on SDN technology,this paper researches a space-earth SDN network architecture model in which the ground and GEO satellites are control plane,and the LEO and MEO satellites are data plane.For the problem of large overhead between devices in space-air network and satellite node load limitation,this paper proposes that the GEO control layer adopts a hierarchical architecture.The main controller has global information of the network,and the local controller only needs to manage the switches in the area,therefore it can reduce with the main controller's frequent interaction.The ground control layer can be used as a backup of the GEO layer master controller to achieve information sharing on the global network,and at the same time avoid the problems of the failure of the GEO layer master controller or link failure.This model facilitates the control of the space-earth network and enhances the reliability,availability,and scalability of the network.(2)Based on the GEO Hierarchical controller deployment method,a load balancing mechanism is proposed.Through the analysis of the functions and requirements of the system,this paper focuses on designing functional modules of the distributed controller system of the SDN network.Floodlight,an SDN controller that is suitable for scientific research is used.The main functional modules include a communication module,a database read/write module,a load measurement module,a load request module,a load collection module,a load decision module,and a switch migration module.Through the interaction of various modules,a hierarchical Multiple controllers' communication and load balancing mechanisms are implemented.(3)This paper uses the Mininet to simulate and test.We use Cbench to test the performance of the Openflow controller to verify the rationality of the proposed architecture.Furthermore,we simulate the different load of the controllers and analyze their resource utilization,throughput,and response time factors on the proposed GEO-based hierarchical architecture by using load balancing mechanism.As for the impact of the whole system throughput and the response time,we compare the ECSM algorithm,the PASMM algorithm with the proposed algorithm,and verify the superiority of the proposed algorithm.