• internet of things
• interoperability
• Java
• smart home

The recent advancements of the building automation in the technological revolution of the Internet of Things (IoT) are leading to the need to enable the communication between devices extremely different from each other. Smart objects equipped with communication capabilities may rely on proprietary IoT solutions consisting of various hardware and software components, that would not be able to be interworked.
Several companies are developing advanced IoT software frameworks, e.g. AllJoyn, which enable interoperability between devices across multiple architectures and protocols. These frameworks provide resource discovery, data transmission and device management, and they support several platform and language bindings.
Despite their great effort, further improvements are still needed, due to technical limitations and framework availability of low-power devices in pre-existing networks. An example is the Constrained Application Protocol (CoAP), a redesign of the popular HTTP protocol that aims to support heavily resource-constrained devices for machine-to- machine (M2M) applications.
In this work we present the design and the implementation of an application that acts as a bridge between an AllJoyn network and a pre-existing one based on CoAP, in order to enable the resources provided by resource-constrained nodes to be reached by a more powerful network, which also includes computers and smartphones.
The bridge allows on-demand registration of CoAP resources, dynamically translated and advertised on the AllJoyn network, so that AllJoyn client applications can easily discover and interact with them.
Experimental tests show the proper functioning of the bridge, the transparent way it operates, and the amplitude of its application. These tests validate the work with both an ad-hoc client application and an already existing AllJoyn application.