In the field of IoT, communication between sensors and servers, information collection, and MQTT protocol are all options that can be considered. MQTT is often used in scenarios that require low power consumption and low bandwidth, such as IoT devices, sensor networks, mobile applications, etc. Its lightweight and efficient features make it very suitable for use in resource-constrained devices and unreliable network environments.

What is MQTT protocol

MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol designed for resource-constrained devices and low-bandwidth, unreliable network environments. It was originally developed by IBM and has become one of the standard protocols in the field of Internet of Things (IoT). The main features of MQTT include:

Publish/Subscribe model: MQTT uses the publish/subscribe (Pub/Sub) communication model, which is different from the traditional request/response model. In this model, clients can publish messages to a topic, and other clients interested in the topic can subscribe to the topic and receive corresponding messages.

Lightweight and efficient: The MQTT protocol header is very small and has low overhead, making it suitable for bandwidth-constrained network environments.

Reliability: MQTT provides three different quality of service (QoS) levels to ensure the reliability of message delivery:

QoS 0: At most once

QoS 1: At least once

QoS 2: Exactly once

Persistent session: MQTT supports persistent session, that is, after the client disconnects, the server can save the client's subscription information and unreceived messages, and when the client reconnects, it can continue to receive unreceived messages.

Retained message: The publisher can send a message with a retain flag, and the server will save the message and send it to the subscriber when a new subscriber subscribes to the topic.

Will message: The client can specify a will message when connecting. When the client accidentally disconnects, the server will publish the will message to the specified topic.

Security: MQTT can be encrypted through TLS/SSL to ensure the security of transmitted data. In addition, MQTT also supports username and password authentication mechanism.