Testing and evaluating a secure-aware pub&sub protocol in a fog-driven IoT environment

The continuous spreading of innovative applications and services, based on the emerging Internet of Things (IoT) paradigm, leads to the need of even more efficient network architectures/infrastructures, in order to support the huge amount of information to be transmitted in real-time. Hence, new protocols and mechanisms must be conceived to allow the IoT network to be more reactive towards environmental changes and in promptly satisfying the IoT users' requests. Aiming at dealing with the emerged issues, the scope of the present paper is twofold: (i) describing a running IoT platform, which exploits fog computing principles to act as a middleware layer between data producers and consumers, in order to properly manage the transmitted data; the proposed architecture adopts a secure-aware publish&subscribe protocol, based on MQTT, coupled with a network of brokers, which are in charge of effectively performing the information sharing task towards end-users; (ii) conducting a test campaign on a prototypical implementation of the just mentioned platform, for preliminary evaluating its efficiency, in terms of computing effort and latency. The test-bed implies the use of Raspberry Pis, which run different instances of the IoT platform, so as to realize a distributed and, possibly, scalable, middleware layer, following a fog-driven approach.