A Discovery Pull Model for Devices in IoT and WoT Environments
Juan Alberto Llopis, Javier Criado, Luís Iribarne, Nicolás Padilla · 2021
A current issue in the Internet of Things (IoT) is the heterogeneity of the devices. Devices with the same functionality have different ways to operate and communicate. A developer interacting with many devices with the same features but from different providers may have to develop software adapted to two problems. The Web of Things (WoT) was born to solve this problem, to establish a common way for interaction and management between IoT devices. However, to apply the solution proposed by the WoT, each device deployed must use a common device definition language, the Thing Description (TD). The use of the TD may require the modification of the device to allow the usage of the TD. After IoT devices are adapted to WoT technology, a way of searching and registering the devices deployed is needed. The registration of devices in a discovery service is performed by an external user or by the device. The registration by the device requires a modification to know the location of the discovery service. Therefore, the discovery and transformation of an IoT device to the WoT need a manual process that increases the workload of developers in large IoT scenarios. In this article, we propose a Discovery Service capable of working proactively in a pull configuration, searching for MQTT devices deployed in the subnet. Furthermore, with the information extracted from the broker, we present an automatic approach to build Thing Descriptions of the discovered devices, transforming IoT devices into WoT devices.