MQTT Essentials Series

Overview

• Discussion on main features and characteristics of MQTT
• Explanation of why MQTT is powerful for IoT

What is MQTT?

• Internet of Things (IoT) messaging protocol
• Built upon TCP/IP
• Minimal overhead, simple, and reliable
• Designed for communication over unreliable channels (e.g., poor Wi-Fi, mobile network)
• Ideal for scenarios with frequent connectivity interruptions (e.g., cars driving through tunnels)
• Easy to implement and use

Characteristics of MQTT

Binary Protocol

• More efficient for machines compared to text-based protocols (e.g., HTML, HTTP)

Efficiency

• Built around maximum efficiency
• Smallest MQTT packet is 2 bytes

Bi-directional Communication

• Allows data transfer from device to cloud and back

Data Agnostic

• Protocol is indifferent to the data format
• Supports various formats (XML, JSON, custom formats, Google Protocol Buffers, even images or video fragments)

Scalability

• Can support connections for millions of devices
• Push communication for low latency
• Enables millisecond latency from device to device over the internet

Built for Constrained Devices

• Suitable for devices with limited computing power and memory
• Libraries available for various programming languages (Arduino, Python, Java, C, C#, Go, Rust)

MQTT Technology Stack

• Requires TCP
• Common stack: IP -> TCP -> MQTT
• Uses persistent TCP connections
• Heartbeat mechanism to handle half-open socket problems
• Supports TLS for encrypted connections (TCP -> TLS -> MQTT)
• Benefits from state-of-the-art libraries like OpenSSL

Advantages of Using TCP with MQTT

• TCP guarantees reliable, ordered, and error-checked packet transfer
• MQTT leverages these benefits for efficiency

Next Topics

• In upcoming videos, we'll discuss how MQTT works
• Focus on publish/subscribe model

Closing

• Reminder to subscribe for weekly videos (MQTT Monday)
• Stay tuned for the next video