How to monitor OpenFlow messages with packet sniffer

OpenFlow was initially introduced in the academia as a way to enable innovation on production networks which had traditionally been built with close and proprietary networking hardware. OpenFlow offloads the high-level routing/forwarding decisions (control plane) from networking devices such as switches, and moves the control plane on to a separate controller. The networking devices then simply forward traffic, as instructed by the external OpenFlow controller. It is the OpenFlow protocol that is used by the OpenFlow controller to program the networking devices.