MQTT Algebraic Formal Modelling Using ACP

Internet of Things special nature brings new challenges as to what communication protocols better suit its features, because the most popular ones nowadays, based on client-server or peer-to-peer paradigms, do not fit properly as they may not meet IoT challenges. However, communication protocols based on a central entity called broker fulfill those requirements, since they help end devices to offload their tasks, thus improving the overall system performance. Among those IoT-based protocols, MQTT is one of the preferred choices, as being lightweight, bandwidth-efficient, low-energy consuming and capable of offering reliable messaging. In this paper, MQTT is selected in order to perform a study on its behavior by means of a simplified model built by using an abstract algebra called Algebra of Communicating Processes (ACP). In this context, first, the entities taking part are modeled, then, specification is carried out, and finally, verification is undertaken, showing that the model proposed meets the requirements expected for MQTT.