Proactive Load Shifting for Distributed SDN Control Plane Architecture

Balancing the workload among distributed SDN controllers plays a critical role for both the network performance and the control plane scalability. Several distributed SDN controller architectures have been proposed to mitigate the risk of controller overload and failures. However, many of these architectures fall short for maintaining the same level of complexity in the control plane. A core implication of complex control plane can translate to a limitation in functional improvements of existing implementation. To address this issue, we propose a novel Proactive Load Shift (PLS) technique that augments the traditional SDN architecture with a shim layer to diminish the complexities in existing distributed SDN controller architectures. While our primary focus is on efficient workload distribution among SDN controllers in a distributed architecture, our shim layer also serves as a programmable abstraction for supporting new network functionalities in the SDN control plane and the data plane without infringing the SDN principles. To achieve optimal network performance in our proposed technique, we eliminate the need for inter-controller synchronization by delegating the synchronization sequence to the shim layer at a per-need based only. Our experimental results show that the PLS technique provides efficient responses to load balancing triggers with less overhead on the control plane.