QoS levels (0, 1, 2) in IOT Protocols - Mini Project: Build & Apply

Understanding MQTT QoS Levels (0, 1, 2)

📖 Scenario: You are working with IoT devices that send messages to a central server using MQTT protocol. MQTT supports three Quality of Service (QoS) levels: 0, 1, and 2. Each level defines how messages are delivered and acknowledged to ensure reliability.Understanding these QoS levels helps you configure your devices to balance between message delivery assurance and network usage.

🎯 Goal: Build a simple Python dictionary that represents MQTT messages with their QoS levels, then filter and display messages by a chosen QoS level.

📋 What You'll Learn

Create a dictionary named mqtt_messages with message IDs as keys and their QoS levels as values.

Create a variable named selected_qos to hold the QoS level to filter messages.

Use a dictionary comprehension to create a new dictionary filtered_messages containing only messages with the selected_qos.

Print the filtered_messages dictionary.

💡 Why This Matters

🌍 Real World

MQTT is widely used in IoT devices to send sensor data or commands. Understanding QoS levels helps ensure messages are delivered reliably according to the needs of the application.

💼 Career

Knowing how to handle MQTT QoS levels is important for IoT developers, DevOps engineers managing IoT infrastructure, and anyone working with message brokers and device communication.

1

Create MQTT messages dictionary

Create a dictionary called mqtt_messages with these exact entries: 101: 0, 102: 1, 103: 2, 104: 1, 105: 0 representing message IDs and their QoS levels.

IOT Protocols

# Create the mqtt_messages dictionary with message IDs and QoS levels
# Your code here

Need a hint?

Use curly braces {} to create a dictionary with keys as message IDs and values as QoS levels.

2

Set the QoS level to filter

Create a variable called selected_qos and set it to 1 to filter messages with QoS level 1.

IOT Protocols

mqtt_messages = {101: 0, 102: 1, 103: 2, 104: 1, 105: 0}
# Set selected_qos to 1
# Your code here

Need a hint?

Assign the integer 1 to the variable selected_qos.

3

Filter messages by selected QoS

Use a dictionary comprehension to create a new dictionary called filtered_messages that includes only the entries from mqtt_messages where the QoS level equals selected_qos.

IOT Protocols

mqtt_messages = {101: 0, 102: 1, 103: 2, 104: 1, 105: 0}
selected_qos = 1
# Create filtered_messages dictionary with messages having QoS == selected_qos
# Your code here

Need a hint?

Use {key: value for key, value in dict.items() if condition} syntax for dictionary comprehension.

4

Display filtered messages

Write a print statement to display the filtered_messages dictionary.

IOT Protocols

mqtt_messages = {101: 0, 102: 1, 103: 2, 104: 1, 105: 0}
selected_qos = 1
filtered_messages = {msg_id: qos for msg_id, qos in mqtt_messages.items() if qos == selected_qos}
# Print the filtered_messages dictionary
# Your code here

Need a hint?

Use print(filtered_messages) to show the filtered dictionary.