Software-defined networking (SDN) is a new paradigm that allows network switches to provide a per-flow data path to satisfy an application-specific purpose. Since the data path is open to modification by an application, the current standard SDN protocol is called OpenFlow. OpenSDWN is a platform for extending the SDN to Wi-Fi to control Wi-Fi characteristics as well as the data path. There have been several studies on controllable Wi-Fi, because a wireless channel is a valuable resource and there is a need to increase its performance. Compared to other approaches, an SDN-based approach has advantages, including exploiting existing SDNs and network function virtualization (NFV) and compatibility with today’s Wi-Fi media access control (MAC) and physical layer (PHY) specifications.

A main contribution of this paper is its presentation of a platform that facilitates the easy handling and migration of per-client state by unifying the SDN and NFV. It also allows per-flow transmission setting based on packet classification and tagging technology. A participatory interface is also provided to allow applications to request an application-specific network policy. Through evaluation, the authors show several benefits of OpenSDWN. OpenSDWN allows: (1) a specific flow to have priority; (2) direct multicast service (DMS) without a client signaling; and (3) user mobility without reinstallation of per-client state. The detailed implementation description in the paper will be helpful to interested readers.

Since a wireless channel is shared among nearby users, changing Wi-Fi characteristics can cause unexpected results. For example, transmission power reduction for a flow can result in information asymmetry among neighbor nodes, which can increase the number of hidden terminals. Thus, experiments in various environments are necessary.