The Community Characteristic Based Controller Deployment Strategy for SDNs

To solve the bottleneck of a single controller in software-defined networks (SDNs), most of current works based on multiple controllers focus on decreasing propagation delay between the switch and the corresponding controller. However,this kind of methods ignores the synchronization between controllers, which may affect the network performance. Moreover, the controller deployment based on out-band has neglected the association between switches, which is quite costly. In this paper, we propose a community characteristic based strategy to achieve controller placement with optimal latency and balanced controller load. We first divide the network domain according to the relevance between switches, and then we design our controller deployment strategy by reconciling the propagation delay between controllers and the control delay between controllers and switches. We adopt in- band control mode instead of Euclidean distance to compute the distance among network entities. The simulation results show that our strategy can gain lower propagation delay latency and better load balance.