Empowering Software Defined Network controller with packet-level information

Packet level information, such as packet content and inter-arrival time, are necessary for some network monitoring and control applications. However, current Software Defined Networks (SDN) such as OpenFlow provide limited access to packet-level information in the controller. In this paper, we propose an extension that enables the controller to access packet-level information through per-flow sampling. Our extension is flexible and powerful, yet it can be implemented entirely in the data plane at line rate. We present a set of possible applications that can take advantage of this new packet-level information, including examples that are extremely difficult, if not impossible in current SDN.