PID-based Adaptive Control Plane Management Method for Software-Defined Networks

Software-Defined Network (SDN) is an emerging network paradigm which enables flexible network management by separating control plane from data plane. Since SDN adopts a centralized management scheme, with large scale SDN network, it brings intensive overhead to control plane. One way of limiting this overhead is to either distribute the overhead to multiple controllers, or offload the overhead to switches. However, both of the approaches require modification on SDN de-facto standard, therefore, it is not viable for practical use. As an alternative solution, we propose a new control plane management method without changing the underlying SDN protocol. The key idea of the proposed method is to maximize the switch resource utilization by maintaining as much information as possible inside the switches, so that the switches may less frequently query the controller for new information. However, it is non-trivial problem to control the switch resource utilization under the capacity, due to the absence of a detailed correlation model between resource utilization and the affecting parameters. To resolve this issue, our management method adopts a lightweight feedback loop based control scheme - Proportional-Integral-Derivative (PID) to adaptively tune the affecting parameters to minimize the control plane overhead, while avoiding the switch's resource exhaustion. We design and implement the proposed method as an SDN application and evaluate its performance in an emulated network.