Enhancement of Reliability of Message Delivery in Many-Subscriber MQTT Networks

A message protocol called message queuing telemetry transport (MQTT) is being used in large-scale energy-efficient communications. However, even when using MQTT, if the network quality and capacity are insufficient, especially when there are many subscribers, nodes may fail to receive messages. Therefore, we propose a new communication control mechanism, eXchanging attributes of transmission uniformity (Xatu). The goal of Xatu is to establish a reliable new method that can compensate for message loss even in long-time and large-scale environments. Xatu sets up a state called bridge, and a conventional MQTT subscriber switches to a bridge. Xatu allows messages to be sent to all subscribers without missing messages.