SN consists of a set of sensor nodes and one or more sink nodes that are deployed over a monitoring area of interest in a structured or unstructured way (Khan, 2016). Wireless sensor nodes are generally operated by battery power thus requires an energy efficient operation to prolong the network lifetime. In recent years, software defined networking (SDN) paradigm emerges as a new network design mechanism where control logic is decoupled from the network devices and leaving the network device with only data forwarding logic (Kreutz, 2015; Nunes, 2014; Jagadeesan, 2014; Bizanis, 2016; Jarraya, 2014; Olivier, 2015). This new paradigm offers various advantages over traditional paradigm such as energy efficient network operations, energy efficient resource allocations and flexible network management, multiple applications deployment and control over sensor nodes etc. (Haque, 2016; Gante, 2014; Luo, 2012; Zeng, 2013). The application of the SDN paradigm in the design of WSN emerges a new network called software defined Wireless Sensor Networks (SDWSNs). In SDWSN, most of the energy demanding operations such as routing decision, duty cycling, topology management, resource allocation, network coverage and connectivity planning etc. are migrated to the logically centralized SDN controllers, thus saves a lot of node energy (Kobo, 2017). This book chapter first discuss generic model for SDWSN and presents different components of this model and its interactions in details. Next, it summarizes the various advantages offered by SDN paradigm to the WSN. SDN paradigm based Protocol design for Wireless Sensor Networks are discussed in Section 4. Finally some open research challenges are discussed in Section 5 and Section 6 concludes the book chapter. SOFTWARE DEFINED NETWORKING MODEL FOR WIRELESS SENSOR NETWORKS Traditional architecture of a sensor node contains full fledge functionality with physical layer up to application layer. This traditional model of a sensor node makes it self-configurable and equipped with the ability to