The Research on Flow Table Optimization Based on Dynamic Timeout Mechanism

SDN(Software Defined Networking) is a new network architecture, which decouples the control plane from data plane and operates the globle network with elaborate abstraction. The control plane advocates a centralized approach of network control, which provides both flexibility and high efficiency. However, there are lots of problems in this architecture and the bottleneck problem is the network's performance. Existing OpenFlow based flow expiry mechanisms relys on a fixed timeout after which the switch proactively removes the flow entries from its flow table which may causes unnecessary flow table occupation. Therefore, in this paper, a strategy of dynamically adjusting timeout time is proposed and the program is implemented. It can dynamically adjust the timeout time according to the actual situation of equipment and data flow, and can better adapt to the network with different data flows. The experiment shows that the strategy can improve the network's performance and the mechanism designed in this paper is proved to be effective.