Introduction to MQTT
MQTT is a fast, lightweight, and simple messaging protocol that enables devices to communicate with each other over the internet. It is an ideal protocol for low-power devices in the internet of things (IoT) because it uses a publish/subscribe model, which requires very little bandwidth and can be easily implemented on devices with limited resources.
In the past few years, there has been an increasing interest in MQTT as a protocol for the IoT. This is because MQTT can provide a way to connect many different types of devices and sensors in a simple and standard way. Using MQTT, developers can create applications that can monitor and control these devices without dealing with the underlying communication protocols.
Many different brokers support the MQTT protocol (mosquito, HiveMQ, etc.). In this article, we will be using the open-source broker Mosquitto.
What is the Internet of Things (IoT)?
The Internet of Things refers to the growing network of physical objects connected to the internet. These objects are equipped with sensors and other devices to collect and exchange data. The IoT has the potential to transform the way we live, work, and play by making everyday objects more connected and intelligent.
One of the critical technologies that are enabling the IoT is MQTT (MQ Telemetry Transport). MQTT is a lightweight publish/subscribe messaging protocol that enables devices to communicate with each other over the internet. MQTT is an ideal protocol for use in the IoT because it is designed for constrained devices and networks, has a small footprint, and is easy to implement.
How MQTT Works
MQTT is a publish/subscribe messaging protocol for constrained Internet of Things devices. It is lightweight, open, simple to use, and suitable for constrained environments such as low-power sensors or mobile devices. These characteristics make it ideal for use in many internets of things applications.
The MQTT protocol establishes a connection between a publisher and a broker. The publisher sends messages to the broker, which then distributes the messages to subscribers. The subscribers can connect to the broker directly or through another intermediate device.
For a device to connect to an MQTT broker, it needs to have an MQTT client library installed. There are many different MQTT client libraries available for a variety of platforms.
Once a connection is established, the publisher can start publishing messages. Each message has a topic, which the broker uses to determine which subscribers should receive the message. The topic can be any string, but it is often structured to describe the message’s content (for example, “sensor/temperature”).
The publisher can also specify what kind of delivery guarantee it requires: whether the message should be delivered at most once (fire-and-forget), at least once (acknowledged), or exactly once (assured). The quality of service (QoS) level is specified when the message is published and cannot be changed later.
Benefits of MQTT
MQTT has many benefits, making it an attractive protocol for use in the world of IoT. One key benefit is its low bandwidth requirements, which make it ideal for devices with limited resources or applications where data usage must be kept to a minimum. Another advantage is its publish/subscribe messaging model, which can offer greater flexibility and scalability than traditional point-to-point communication models. Additionally, MQTT has built-in support for security and reliability features such as Quality of Service (QoS) and testament (LWT), which ensure that messages are delivered safely and reliably even in hostile or resource-constrained environments.