Review of Interoperability approaches in Application Layer of Internet of Things

Internet of Things (IoT) encompasses numerous old and new technologies under its umbrella; which means there is a huge diversity in types of devices, protocols and mechanisms that are to be supported. Things by themselves need to inter-network and collaborate to provide the necessary level of service expected out of them, working in isolation does not help in many cases. Interoperability issues have been attempted to be solved in broadly five different ways - publishing standards, reference architectures and frameworks, defining protocols and media-type standards and by using abstract interface definition languages and semantic ontologies. An interoperable environment requires a well-established data-model to provide properties, behavior and message formats and a framework to support selecting the right protocol along with an ontology indicating what the data means based on the context. Application layer is the primary interface for interacting with the systems and services; hence it makes it important to provide an interoperable environment at this layer enabling dynamic composition and rapid development of new services. IoT requires a common construct that is adaptive, expressive and dynamic in nature abstracting out the communications, behavior and models that allows diverse set of device stacks to interoperate. Such constructs enables device vendors to publish changes systematically and incrementally without affecting the advances in the rapid development of applications.