Design and Performance Evaluation of a Standalone MQTT for Sensor Networks (MQTT-SN) Broker

The Message Queuing Telemetry Transport (MQTT) protocol is a de-facto standard for machine-to-machine (M2M) communication in the Internet of Things (IoT) domain. However, since it is limited to TCP at transport layer, it is not possible to run MQTT over UDP, which would be desirable for real-time capable publish/subscribe. MQTT for Sensor Networks (MQTT-SN), which is a lightweight version of MQTT, allows the use of UDP, however, is strongly coupled to MQTT by the current specification and cannot be operated independently of it. In this work, we therefore propose a standalone broker implementation of MQTT-SN. In initial measurements, we can show that our approach is much more performant than the approach described in the specification and that our implementation compares very well with the protocols CoAP Pub/Sub and MQTT.