The Message Queuing Telemetry Transport protocol (MQTT) is a publish/subscribe message protocol designed for networks with limited bandwidth and IoT devices with extremely high latency (delay in DATA transmission). This messaging protocol is simple and lightweight, suited to devices and networks with low bandwidth, high latency, or insecure networks. It has been designed to reduce network bandwidth and resource requirements of devices and to ensure supply security. Furthermore, these principles are beneficial for IoT or M2M devices, SINCE battery life and bandwidth are very important. Because MQTT is efficient and lightweight, it can be used to monitor or control a large amount of data. Nowadays, MQTT is used in a variety of industries, including automotive, manufacturing, telephony, oil and gas. 

Publishes are the sources of data that send data to TOPICS. The broker MANAGES the topics, and consumers subscribe to the topics. Upon receiving data for a topic from the publisher, the broker forwards it to all SUBSCRIBED consumers. As a result, brokers are responsible for receiving data from publishers and sending it to the appropriate consumers.