A Modular Distributed IoT Service Discovery

The Internet of Things (IoT) consists of distributed entities that federate to implement use cases. Driven by its applications, distributed IoT services federate dynamically to deliver complex functionality. A fundamental requirement for service composition is discovery. The IoT requires a semantically-rich, dynamically extensible, low complexity service discovery mechanism. Existing mechanisms fail in delivering this functionality. We present a distributed modular directory of service properties. It can be extended at runtime. Combined our so-called search provider directories form an IoT ontology. With the novel modularization, our simple directories mash-up to a complex ontology. We introduce a query federation mechanism. Based on first-order logic it enables mapping complex semantic queries on the simple search providers. We evaluate our prototype regarding latency and usability.