Understanding MQTT Protocol and History

MQTT Protocol

• MQTT is a messaging protocol used for machine-to-machine communication
• It's used by IoT (Internet of Things) devices to transmit and receive data over networks with limited bandwidth
• MQTT is lightweight, efficient, scalable, reliable, and secure
• It supports messaging between devices and the cloud, and between the cloud and devices
• MQTT uses a publish/subscribe model where a central broker manages communication
• Publishers (devices) and subscribers (other devices) communicate without knowing each other's network details
• Publishers and subscribers don't have to be active or connected at the same time
• Publishers and subscribers operate independently
• MQTT clients use an MQTT library to act as publishers and subscribers
• The MQTT broker receives, filters, and distributes messages to subscribed clients

MQTT History

• Invented in 1999 for the oil and gas industry
• Initially known as Message Queuing Telemetry Transport
• IBM product MQ Series supported its early phase
• Released as a free and open protocol in 2010 (MQTT 3.1)
• Standardized by the Organization for the Advancement of Structured Information Standards (OASIS) in 2013
• Upgraded to MQTT version 5 in 2019
• MQTT is now the official name of the protocol

MQTT Components

• MQTT Client: A device (e.g., sensor, mobile device, backend system) running an MQTT library
  • Acts as a publisher when sending messages
  • Acts as a subscriber when receiving messages
• MQTT Broker: Coordinates communication
  • Receives, filters, and distributes messages to subscribed clients

MQTT Topic

• Keywords used by the MQTT broker to filter messages
• Organized hierarchically like folders
• Example: ourhome/groundfloor/livingroom/light for a smart home system

MQTT Publish

• MQTT clients send messages containing a topic and data in bytes
• Data formats like text, binary, XML, or JSON
• Example: A smart lamp publishing livingroom/light

MQTT Subscribe

• MQTT clients subscribe to topics of interest
• Contains a unique identifier and a list of subscriptions
• Example: A smart home app subscribing to the light topic to display the status of lights in a room

MQTT over WSS

• MQTT implementation for direct data receiving into a web browser
• Adds headers to MQTT messages for web socket support

MQTT Security

• MQTT uses SSL and certificates for secure data transmission
• Implements identity, authentication, and authorization between clients and the broker.
• MQTT brokers authenticate clients with passwords or unique identifiers
• Clients can authenticate with certificates.

MQTT and REST

• MQTT is not RESTful
• Instead of a request-response pattern, it uses a publish-subscribe model with a continuous connection.
• Version 5 has a method for request/response interaction.

MQTT and HTTP Comparison

• MQTT is lightweight and efficient for resource-constrained devices, good for IoT devices
• HTTP is suitable for general-purpose communication over the web

MQTT and COAP Comparison

• MQTT is a more general-purpose protocol, whereas COAP is designed for constrained devices

Modbus TCP vs. MQTT

• Modbus TCP is point-to-point, good for on-premise machine-to-machine communication.
• MQTT is publish-subscribe, suited for scalable machine-to-enterprise or cloud communication.

This quiz explores the MQTT protocol, its applications in IoT communication, and its history. Learn about its lightweight architecture, the publish/subscribe model, and how it has evolved since its invention in 1999. Test your knowledge on its key features and functionality.