Routing under Heterogeneity and Mobility for the Internet of Things - A Centralized Control Approach.

Being part of the Internet of Things (IoT), the Wireless Sensor Networks (WSNs) inherit characteristics such as large-scale deployment, dynamicity, heterogeneity and mobility. These aspects mandate elasticity in many network functions and especially in routing. The IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) is the state-of-the-art routing protocol for resource-constrained devices in environments with signal issues, but it was not designed to support mobility. However, mobility is fundamental in critical WSNs applications, e.g., it improves sensing coverage and brings back connectivity. In this paper, we propose a centralized routing control approach, which exploits the global view of the network inspired by the Software-Defined Networks (SDNs), in order to provide dynamic end-to-end routing service in heterogeneous environments. We briefly present our novel Cross-Layer Control of Data Flows (CORAL) framework, which-in the context of the current work-has been enhanced with management and control features to provide elasticity in the RPL's functionality. In practice we developed and propose dynamic and individual parameters' configuration and adaptation, live monitoring of performance through visualization and Ansible-based protocol's deployment. Our results show that dynamic RPL configuration, which tackles mobility issues on-the-fly, along with individual configuration which handles them separately, can efficiently tune the protocol's performance trade-offs, e. g., between packet delivery ratio (PDR) and routing overhead, bringing up to 35% improvement in PDR and offloading the control overhead from the mobile nodes.