From IoT to Cloud: Applications and Performance of the MQTT Protocol

A study of the MQTT publish/subscribe protocol with different QoS levels is presented with the aim to extend the Internet of Things (IoT) concept across access, edge and transport networks and reach cloud computing facilities. A simple testbed is set up with related software components to measure the end-to-end delivery latency between the publisher and the subscribers and the impact of the network delay caused by network configurations with different service deployments. In particular, the latency is shown to rise up to more than 7 times the average network delay when the QoS 2 level is applied, thus indicating that its adoption must be carefully considered.