MQTT

Table of Contents

1. MQTT Architecture
2. MQTT Communication Flow
3. MQTT Configuration
4. MQTT Explorer Setup
5. MQTT Integration Benefits

Overview

MQTT (Message Queuing Telemetry Transport) is a lightweight communication protocol designed for IoT devices and efficient message transmission in bandwidth-constrained environments.

MQTT Architecture

Core Components

1. Clients - Publishers: Send messages to specific topics - Subscribers: Receive messages from subscribed topics - Dual Role: Clients can both publish and subscribe

2. Broker - Message Distribution: Central server managing message routing - Topic Management: Handles topic subscriptions and publications - Client Coordination: Manages connections and message delivery

3. Topics - Message Categories: String-based channels for message organization - Hierarchical Structure: Support for complex topic hierarchies (e.g., home/livingroom/temperature) - Subscription Management: Clients subscribe to topics of interest

MQTT Communication Flow

Connection Process

1. Client Connection: Connect to MQTT broker with IP address and port
2. Authentication: Provide credentials if required
3. Topic Subscription: Subscribe to relevant topics
4. Message Publishing: Publish messages to topics
5. Message Distribution: Broker delivers messages to subscribers
6. Quality of Service: Message delivery guarantees based on QoS level

Quality of Service Levels

QoS Level	Guarantee	Description
QoS 0	At most once	No delivery guarantee, possible message loss
QoS 1	At least once	Guaranteed delivery, possible duplication
QoS 2	Exactly once	Guaranteed delivery without duplication

MQTT Configuration

Connection Settings

Broker Details: - Host: 127.0.0.1 - Port: 8080 - Username: admin - Password: admin

Connection Credentials

Use the default credentials for local MQTT broker access.

MQTT Explorer Setup

Publication Configuration

Create publication files in your project directory:

File Path: ../sample/app/mqtt/room1.pub Relative Path: app/mqtt/room1.pub

File Content:

room1 RoomTemp1  // [group-name] [message-name]
room2 RoomTemp1

MQTT Explorer Installation

Download MQTT Explorer

MQTT Explorer Download

Explorer Configuration

Configure the MQTT Explorer with your broker settings for real-time message monitoring.

Live Monitoring

Monitor real-time MQTT message flow and topic activity through the graphical interface.

MQTT Integration Benefits

• Lightweight Protocol: Minimal bandwidth usage for IoT applications
• Real-time Communication: Instant message delivery and updates
• Scalable Architecture: Support for numerous connected devices
• Reliable Messaging: QoS levels ensure appropriate delivery guarantees
• Flexible Topics: Hierarchical topic structure for organized messaging