No way back? An SDN protocol for directed IoT networks

The Internet of Things (IoT) has and will continue to permeate many aspects of everyday life. However, IoT devices often use wireless communication to transfer their data, which may experience ambient noise and multipath fading. This, together with the wide heterogeneity in types of devices, leads to the emergence of unidirectional links in IoT networks. Surprisingly, many routing protocols for wireless networks either do not account for such links or employ radical mechanisms, like blacklisting. In this paper, we leverage the features of Software-Defined Networking (SDN) to develop a network discovery algorithm that is able to cope with unidirectional links, while containing the control overhead. We provide a proof-of-concept implementation of an SDN protocol for constrained devices that uses our algorithm and perform experiments. The experiment results show that our solution is scalable and performs well both for unidirectional links as well as for fully bidirectional networks.