Enhanced South-Bound Communications for Underwater Acoustic Software Defined Networks

The Internet of Underwater Things (IoUT) paradigm exploits underwater communication networks to interconnect a possibly large number of cheap, low-powered devices, thus enabling such tasks as environmental monitoring and data telemetry. Due to the communication technology used, typically based on acoustic signals, the IoUT requires specific deployment planning in order to be functional and efficient. This may make Software Defined Networking (SDN) techniques useful in IoUT scenarios as well, despite being traditionally used for terrestrial networks. However, classic SDN message exchanges between a controller and multiple devices (the so-called 'south-bound' communication) requires a high number of reliable message exchanges, and does not fit the IoUT use case well. In this paper, we present a custom south-bound communication protocol that takes advantage of underwater network characteristics in order to enable the SDN paradigm in IoUT networks. Our results show that, by exploiting the properties of underwater acoustic communications we can solve the most problematic pain-points of underwater SDN while obtaining a significant gain in throughput and energy efficiency with respect to more traditional SDN mechanisms.