Freund, MichaelMichaelFreundFries, JustusJustusFriesHarth, AndreasAndreasHarthSchiller, PeterPeterSchillerDorsch, ReneReneDorsch2024-05-222024-05-222023https://publica.fraunhofer.de/handle/publica/46860510.1145/3627050.36270632-s2.0-85189331166We present WoT2Pod, an architecture that provides a uniform API for data access and control of IoT devices at the edge and in the cloud, creating a seamless continuum between these environments. The uniform API is based on Resource Description Framework (RDF) graphs, Linked Data Platform (LDP) containers, and HTTP. The API is created by a middleware that uses the Web of Things to interact with devices, maps collected IoT data to RDF, provides the most recent data at the edge, and stores data for long-Term storage and sharing with third parties in a Solid Pod in the cloud layer. We establish a formalism and derive equations for predicting latency, and use them to evaluate different polling and pushing-based methods for exchanging data between components. Our results underscore that interactions at the edge are consistently faster than those in the cloud, with data access 65% faster and device control 70% faster. We found that a strategy that relies entirely on pushing data provides the most optimal latency results.enArchitectureInternet of ThingsSolid ProjectWeb of Thingsconference paper