STEP-ONE: Simulated testbed for Edge-Fog processes based on the Opportunistic Network Environment simulator

The Internet of Things (IoT) has evolved from a cloud-based architecture towards multi-layer architectures such as Fog computing, where network edge devices perform processing and messaging tasks. Researchers studied managing and scheduling applications in these architectures extensively, however some issues, especially the effect of mobility, have been less explored. Additionally, evaluation of these mechanisms in realistic scenarios is difficult, as real-world experiments are costly and building composite applications with existing simulation tools is laborious. We call such composite applications which entail functions for handling connectivity and mobility disruptions in the edge network, Edge Processes. In this paper, we present STEP-ONE - a set of tools developed to simulate IoT systems where the management and application composition is handled with Business Process Model and Notation (BPMN) related standards. We demonstrate STEP-ONE with a smart-city scenario, where an application modeled as a choreography of processes is executed between different resources - cloud, fog and moving edge devices. We show how STEP-ONE enables constructing such a scenario and how it can be extended with algorithms and decision-mechanisms to adaptively drive the execution of such processes. We also present how detailed performance metrics can be extracted from the discrete event simulations run with STEP-ONE. (C) 2020 Elsevier Inc. All rights reserved.