Interoperability in the Internet of Things with Asymmetric Schema Matching

Abstract

Interoperability is one of the main challenges of the Internet of Things environments, given the huge number of interconnected devices and the wide range of manufacturers and models. The classical solution, symmetric interoperability, in which both interacting devices share the same data schema, usually leads to a coupling problem, since a device cannot change its schema without changing it as well in the devices with which it interacts. This chapter proposes asymmetric interoperability mechanism, in which the schema used to produce a message does not need to be identical to the schema of the messages expected by the receiver. This leads to a lower coupling level and allows a device to interact with others, which send or receive messages with different schemas, and to replace another one with a new schema without impairing existing interactions. This asymmetry in interoperability is based on the concept of structural compliance and conformance, which state that schemas need only be compatible in the message components that are actually used and not in the full message schema. A simple interoperability framework and a model of coupling, adaptability and changeability are presented to illustrate the impact of these concepts. A few implementation examples are also provided.