TinyOS

(periodically checking if data is available) manner. In-Network Processing: At times WSN need to readily perform data aggregation to reduce data redundancy. This feature is absent in SDN. To tackle this issue, SD-WSN model offers an in-net proc module. If processing is not needed then it simply forwards it to the flow table. In case of making any changes to the algorithm, an over the air programming (OTA) technology can be used to direct the changes. 2.5.2 TinySDN TinySDN is a TinyOS-based Software Defined Networking (SDN) framework designed by (Oliveira et al., 2016). It introduces multiple controllers in the Wireless Sensor Networks (WSN) and has two main components: • SDN sensor node • SDN controller node As discussed by Oliveira et al., their design focuses on the key issues of energy supply, communication latency, and smaller link layer frames. Most of these issues were not addressed by the previously proposed architectures for SDN in WSN. It is also the first SDN based design for devices running TinyOS. Typical WSN devices have only one radio module that transmits or receives signals at a given time. Therefore, data and control planes have to share the same communication link and available bandwidth. This in-band control causes delays in the network. Furthermore the control and data flows must also be separated. As Oliveira et al. mentions, the IEEE 802.15.4 standard provides a very limited bandwidth which results in an average of 250 Kbps increased latency per hop…