s off its radio and goes to the sleep state when it is not in use. Since duty cycling approach offers a huge amount of energy saving, there is a need to design an novel centralized algorithm for designing the optimal duty schedule for each node SO that coverage and connectivity of the network is maintained. Flexible Rules and Policies for Sensor OpenFlow: Since OpenFlow mechanism offers a novel approach to decouple the data and control plane in the SDN paradigm, SDWSN framework needs to focus on designing the simple and flexible rules for sensor Open flow and where to place these rules and policies is an emerging challenge in this area of research. Support of Node Mobility: Since WSN is a application oriented network, node mobility as well as sink node mobility both offers various advantages in order to tackle various challenges such as energy balance problem, coverage and connectivity problem, energy hole problem Since node mobility makes network topology dynamic, there is a design research challenge for SDWSN architecture which can support node mobility. Virtualization of the SDN Controller: Since in cluster based SDWSN architecture, multiple controllers are deployed where each cluster has one controller, how to virtualized multi-controller sensor network and how to organize then is a research challenge. Reliability: Since WSN uses wireless links for the communication and these links are generally unreliable and unstable. Sometimes dynamic network topology may cause unreliable network operations and management by the centralized controllers. The design of protocols for SDWSN should consider these issues also. Optimal Placement of Controllers: In SDWSN architecture, SDN controller plays a major role in topology management, routing, duty cycling etc. However, optimal placement of these controllers and how to distribute loads to these controllers are an emerging research challenge in order to provide scalable solutions. Implementation and Evaluation Over a Sensor Platform: In the literature, there are many researc