Software Defined Networking and OpenFlow have forever changed the landscape of computer networking. Researchers and leading IT corporations have been embracing this evolution in recent years, but greater commercial and industrial acceptance is contingent upon successful “real-world” testing. Testing which focuses on the stability and performance gains SDN/OpenFlow provides. One particular area of performance enhancement is the arena of network security via dynamic administrator control. This paper proposes a framework for large-scale M&S of denial of service attacks against SDN/OpenFlow networks. Beyond the M&S framework research of particular attack methodologies, large-scale tools, and an evaluation of their effectiveness is provided.