High Efficient And Secure Link Discovery And Optimal Controller Deployment For SDNs

In software-defined networks(SDN),the controller grasps the entire network infrastructures and maintains a global view of the network by topology discovery.However,as a key service of topology discovery,the link discovery opens problems on efficiency and security.Besides,the different deployment strategy for multi controllers may have different influence on the efficiency of topology discovery.Hence,the high efficient intra-domain link discovery protocol and the effective inter-domain controller deployment strategy are fatal for the topology discovery of the network.On the one hand,the current link discovery scheme send packets to all ports and the superfluous packets may waste the resources and reduce the link discovery efficiency.Meanwhile,for the lack of authentication of packet,attacker may make use of these superfluous packets or forged packets to carry out link fabrication attacks.In this paper,we propose efficient and secure scheme to improve link discovery performance by eliminating superfluous.The packet authentication method can also resist link fabrication attacks.On the other hand,the Euclidean distance based controller deployment method ignores the association between nodes and the synchronization between controllers will affect the topology discovery efficiency of the whole network.Thereby,the controller placement method that ignores the deployment of networking between controllers cannot get the optimal control delay.Accordingly,we first divide the network domain according to the relevance between nodes,and then design controller deployment strategy reconciling the network between controllers and the control channel between controllers and switches and thus reduce the delay of the network topology discovery.We use the Mininet and POX to evaluate the effectiveness of the intra-domain link discovery scheme and the inter-domain multi controller deployment strategy.The intra-domain link discovery scheme significantly reduces the load of the data plane and the controller.Meanwhile,the inter-domain has a shorter data transmission distance,thus the propagation delay is lower and our deployment strategy is more efficient.