An AllJoyn to CoAP Bridge

Interoperability between smart devices and applications across multiple architectures, platforms and communication technologies is a key challenge for the future Internet of Things (IoT). Many IoT open platforms are being developed to overcome this issue, such as the AllJoynTM framework specified by the AllSeen industrial alliance. Due to heavy resource constraints, however, it is not always a feasible option to run such framework on low-power devices, where other mature technologies like, e.g., Constrained Application Protocol (CoAP), are already successfully applied. In this work we present the design and open-source implementation of an application acting as a transparent bridge between AllJoyn and CoAP networks. The bridge leverages advanced CoAP features, i.e. caching and resource observation, for efficiency and scalability, and provides AllJoyn applications with a rich low-level interface to interact with multiple CoAP servers hosting CoAP resources. The implementation has been extensively validated in a real test case, and proved to properly work in a transparent manner.