“…A new technique that allows the MQTT protocol to cope with distributed brokers for the new IoT challenges was to apply the spanning tree protocol over a network of brokers in order to create a loop-free topology between more brokers [12]. A second example of such application is D-MQTT [30]: this work proposes a distributed version of MQTT, based on the mosquitto broker, where multiple brokers connect with each other through a spanning tree topology, allowing clients to communicate even if originally associated to different brokers.…”