SDN based network access controller: A first milestone

Software Defined Network (SDN) protocols, such as OpenFlow, aim at providing a unified and reconfigurable view of communication networks. SDN protocols are not designed with the ability to act on the upper layer of the network protocol stack, where much could be gained from their capabilities. Using the SDN framework, this paper presents the implementation performance of an innovative mechanism that leverages user traffic to dynamically modify upper network layer behaviour. This generic extension of a SDN controller is particularly well suited to applicative proxies and is sufficiently lightweight to be implemented on generic hardware. This paper demonstrates an application injection and proxy redirection, where OpenFlow is used to tunnel user traffic to an SDN controller that enhances the upper layer network function. We demonstrate the feasibility of modifying application layer protocols on top of TCP by adjusting sequence and acknowledgment numbers. The performance of the current implementation is presented and shows that a single controller can handle thousands of concurrent connections.