Extension of Reception Frequency Control to MQTT Protocol

Abstract

MQTT protocol is widely used for message delivery between sensors and small devices in IoT systems. When using MQTT, it is especially important to reduce unnecessary message delivery. Methods/Statistical analysis: This paper proposes RFC(Reception Frequency Control) algorithm with which subscribers of the MQTT broker can control the maximum reception frequency of messages depending on their own processing ability and thereby the network traffic of the MQTT brokercanbe reduced. Findings: The Mosquitto is an open source MQTT broker that implements the standard MQTT protocol. To verify the effectiveness of the RFC algorithm, we modified the Mosquitto to have the function of RFC and developed a test IoT system. We measured the network traffic of the existing Mosquitto and the modified Mosquitto with the RFC algorithm, respectively. The experimental results showed that the RFC algorithm reduces the message traffic of the MQTT broker extremely as well as keeps the network load of the MQTT broker uniformly. Improvements/Applications: As a result, the RFC algorithm proposed in this paper not only enables low-capability devices or sensors to participate in MQTT based IoT systems,but also drastically reduces message traffic.