SoD-MQTT: A SDN-Based Real-Time Distributed MQTT Broker.

MQTT is currently one of the most widely used protocols at the application layer for the Internet of Things (IoT). To manage an increasing number of IoT devices and optimize the transmission of information, the distribution of the MQTT broker (MQTT cluster) and the integration of the SDN technology in the MQTT architecture are nowadays strongly promoted ideas. Unfortunately, existing proposals have several limitations: 1) they are incompatible with currently deployed solutions, 2) they induce significant delays for information exchange between MQTT brokers within the same cluster, and 3) they do not take into account the distribution of data to the end users (subscribers). That is why, in this paper, we propose a new SDN-based Real-Time Distributed MQTT Broker: SoD-MQTT. The architecture and protocols described aim to minimize communication delays between brokers and to support very low latency applications (e-health, transportation). By leveraging the advantages of SDN, subscription, and publishing can also be efficiently managed. The conducted evaluations demonstrate the relevance of the solution in terms of latency and network utilization optimization compared to existing SDN-based MQTT brokers.