Energy-Aware Optimum Offloading Strategies in Fog-Cloud Architectures: A Lyapunov Based Scheme.

We introduce offloading policies for fog-cloud architectures that consider different performance parameters. We design and develop a three-tier platform, using virtualization techniques, which can be used to deploy different scenarios, with nodes having distinct features, mimicking fog and cloud characteristics. We then exploit Lyapunov's control theory to introduce offloading policies that balance energy consumption at fog nodes and monetary cost of using the cloud. The proposed scheme is able to find a trade-off between these two parameters, while ensuring system stability and so delay requirements. We compare our algorithm with baseline solutions (adapted round-robin), and the results evince that it is able to yield better performance, even under high loads and stringent energy requirements. By tweaking the algorithm operational parameters, we show that it is able to adapt its behavior to different goals, and we assess its performance under realistic configurations.