INTER-LAYER - Middleware to Middleware (MW2MW) Interoperability

Interoperability at the middleware layer is achieved through establishment of an abstraction layer and subsequent attachment of all platforms to it. These attachments are established using bridges abstraction layer. This way we avoid the need to interconnect all platforms among themselves, instead connecting them directly to the abstraction layer and providing a mechanism for their communication within this layer.

Communication at the middleware layer is based on a message broker, which is accessed in every communication performed in MW2MW. This allows both complete decoupling between components and isolation of the communication responsibility in a single element, which in turn makes profiling, scaling and adaptation to enterprise infrastructures easier. Furthermore, the broker is accessed through a general API that exposes basic common operations (message pub/sub, topic creation, basic resources management...), enabling interchangeability of the actual implementation of the message broker.

Data model, used in MW2MW, is based on the ontological reference model of meta-data developed in INTER-IoT. It includes core concepts, shared between IoT platforms, that have been identified and standardized in ontologies, such as SSN (Semantic Sensor Network ontology). Using one common model for all internal MW2MW components improves efficiency of internal data transfer, as well as allows components to make assumptions about structure and content of data, so that rich functionalities specific to IoT domain can be implemented and offered in one common data model. There is, however, no requirement of compliance with the MW2MW data model placed upon platforms that use it. The models of platforms participating in communication through MW2MW are lifted to ontologies and semantically translated in IPSM. As a result, the commonalities between data models of IoT platforms can be expressed in an unified way (i.e. in a common model), despite the possibility of having different semantics.