A proposal on the control mechanism among distributed MQTT brokers over wide area networks

MQTT for IoT communication requires the deployment of multiple brokers to aggregate traffic from localized areas. However, the routing mechanisms among these brokers in a large-scale environment have yet to be specified. In this paper, a routing suitable for up-scaling based on the distribute MQTT broker by data link look up for traffic reduction (DMLT) is proposed. In this study, several up-scaling methods are proposed and compared in terms of traffic volume, scalability, and resilience. As a result, we chose an improved version of DMLT. A prototype of a wide-area DMLT system was constructed and verified by combining the DMLT method with an approach that the authors judged to be the most suitable for large-scale deployment.