OpenFlow is Software Defined Networking, Software Defined Networking is Not Only OpenFlow
The roots of Software Defined Networking (SDN), the predictions for the future of application layer emphasis, and a proposal to create a broader "Big tent" definition. The authors certainly believe SDN should be a big tent and encourage all sorts of means and mechanisms to be born in the virtual networking primordial soup. The behaviors of the Open Networking Foundation will in some ways determine if there is a big tent, or an encampment of tiny tents. If it behaves as "OpenFlow = SDN, SDN = OpenFlow" then that is a possible outcome.