## 2 Related Work  
Extensive research has concentrated on the installation of reliable and affordable WSNs to identify core issues in traditional management systems. Industrial growth requires exclusive management systems to ensure the heterogeneity of network resources and a wide application spectrum. In this regard, significant research work is being conducted on the integration of the SDN management layer with the infrastructure layer of WSNs [21; 22; 23]. All these solutions tend to shift control logics to the centralized controller, and nodes obey their responsibilities of forwarding tasks. Existing research highlights many interesting developments that enable SDN-based networking capabilities for WSNs to enhance application-awareness, wide-area network management and the stability of network performance [24; 25; 26]. By reviewing the related literature in detail, we discuss the following contributions that are vital additions to this paper. The basic SDN-WSN integration architecture is given in [5] by proposing the idea of Software-Defined Networking for WIreless Sensornetworks (SDN-WISE). SDN-WISE attempts to cover the theoretical layout and real-time deployment effort by making WSN nodes programmable during online configurations. However, this requires improvement for a better integration model, with WSNs supporting conventional cluster-based organization to allow practical installations to prosper. In [27], SDN-WSN hybrid inter-networking is proposed while taking care of cluster organization; this integration is known as Software-Defined Clustered Sensor Networks (SDCSN). However, this scheme uses extensive resources by adding multiple BSs playing the role of CHs, and normal nodes only create clusters with these BSs. This architecture adds to the complexity of thenodes, as they act as sub-controllers. Moreover, it supports multiple controllers simultaneously. This causes extensive control message flooding during the setup phase and dissipates major energy resources of the WSNs. Adding to the versatility and flexibility of WSNs, the authors in [6] enabled a Network Management System (NMS) for central management of WSNs at the application level. The additional control layer of an SDN promises application-awareness, but these improvements show limited capacity at the theoretical level and many challenges for real-time execution. Establishing a reliable intra-communication protocol between forwarding logics and central control logics is an additional challenge. This issue is addressed by the Sensor OpenFlow (SOF) [27; 28] SDN-WSN environment. SOF develops flow table instructions generated at the controller to enable physical-layer forwarding tables at the sensor devices. These ideas are key technical contributions and provide intelligent components for advancements in this area. However, for real-time implementations, these ideas need actual prototypes that can offer significant participation. The soft-WSN architecture is proposed in [12]. The overall research proposes energy efficiency and network load-balancing in the hybrid network of the SDN-based Internet of Things (IoT) integration. Network configurations start from the central controller by application layer-defined decision making to ensure the utilization of limited network resources. However, these configurations are static and are not iterative in nature. These shortcomings imply the possibility to enhance the network performance. Another SDN-WSN framework called TinySDN based on Tiny-OS is proposed in [29], which contains multiple SDN-enabled sensor nodes guided by multiple SDN controllers. TinySDN based on Tiny-OS offers in-band control, which causes unacceptable latency and extensive energy consumption due to the lack of iterative clustering efficiency. One of the research surveys reports this system to be vulnerable to security collapse. A similar central management-oriented software-defined sensor networking system was introduced in [30; 31], mainly based on the TinyOS platform.