The Performance and Dependability of Control Plane in OpenFlow Networks

OpenFlow is an innovative approach to manage networks. It separates the control plane out of forwarding devices and uses a centralized controller to manipulate all the forwarding devices. The separation offers many benefits in terms of network flexibility and management. However, these benefits come with a performance penalty. Since the controller manipulates all the forwarding devices, the performance of the controller impacts the performance of the whole network. In addition, the controller is a single point failure of an OpenFlow network. I investigate the performance and dependability of OpenFlow controllers during my PhD. I implement a benchmark tool for OpenFlow controllers to fit the response time of an OpenFlow controller into a PH (PHase-type) distribution. Based on the distribution of response time, I can build queueing models for multiple controllers in an OpenFlow network. Based on the queueing models, the parameters that can minimize the response time of the controllers will be determined. I also use a stochastic model to evaluate the dependability of multiple controllers.