# Software Defined Networking for Improved Wireless Sensor Network Management: A Survey
## 1 Introduction
Much as this works well especially with small-scale short range WSNs due to well-developed algorithms,it lacks simplicity and flexibility making it hard to manage when trying to implement a long range and low power WSN at a large-scale. In order to solve this problem in management of WSNs several techniques have been researched and developed and some of these methods revolve around the concept of Software Defined Networking (SDN). SDN is a new leading architecture for networking [22; 23]. It is based on the principle of dividing and separating the network into two separate planes; the control plane which determines the traffic routes and the data plane which forwards the traffic packets [24]. SDN was initially designed for traditional wired and wireless networks therefore using it for WSNs would pose a challenge due to limited node resources and other constraints inherent in the WSN architecture. There have been some efforts to apply SDN to wireless sensor networking to enable management versatility and flexibility [21] in what are referred to as Software Defined Wireless Networks (SDWSNs). Integration of SDN would enable building of a Network Management System (NMS) to be no different from adding another application to the control plane. It would also allow for a centralized network view which is preferred by network administrators. As a result of the advantages that SDN introduces to ordinary WSNs, applications in SDN-based WSNs are being constantly developed and researched. While several management schemes for WSNs have been proposed and discussed in the past decade [25; 26] and for the general SDN concept in recent years [27], there has been little emphasis on how SDN might improve management of WSNs or on the need for integration of SDN-based management architectures in WSNs. In any network that is expected to scale up to thousands of nodes and greater for use in various applications it is critical that management solutions be considered and developed [25]. There have been survey papers on general SDWSN aspects [28; 29]; however, issues related to WSN management based on SDN which are crucial to the requirements of an efficient WSN are yet to be adequately addressed. Therefore, this paper briefly reviews contributions in management of WSNs and presents a survey of the management techniques in which SDN has been implemented to improve the management of wireless sensor networks. In brief, this paper makes the following contributions. 1. We provide an updated overview of management in WSNs as we review various contributions in network, topology, energy, security, maintenance and monitoring management of WSNs. 2. We review SDN in general while focusing on the adoption of SDN-based management in real-world WSN applications. 3. The general overview of the WSN management architecture based on SDN is presented and we review several contributions in the management entities of the architecture. 4. We identify the requirements for improved and effective management of WSNs leveraging SDN thereby also highlighting available open challenges in SDN-based management for WSNs. The approach for the rest of the paper is as follows: Section 2 presents a background on managing a WSN and Section 3 addresses general network management based on the SDN paradigm. Section 4 reviews real-world WSN applications and the benefits of SDN-based management to these applications. Next, Section 5 focuses on reviewing SDN-based management of WSNs where SDN techniques and proposed architectures for managing the network topology, energy utilization, QoS, enabling software/hardware technologies and security for WSNs based on SDN are presented. Section 6 discusses the overview for SDN-based management in WSNs. In Section 7 several open challenges in management WSNs based on SDN are identified. Finally, we conclude in Section 8.