Optimal master controller assignment for minimizing flow setup latency in SDN

In multi-controller software-defined networking (SDN) environments, a flow whose path includes switches that are managed by different controllers experiences increased flow setup latency, which is critical for delay-sensitive applications. To address the issue, we propose an optimal controller assignment scheme that minimizes the average flow setup latency while limiting load imbalance between controllers. Preliminary simulation results show that the optimal assignment scheme can achieve lower average flow setup latency than a load-based assignment scheme.