Microsoft Azure IoT Developer — Question 30

You have an Azure IoT solution that contains 20 IoT devices. Each device typically sends five Message Queuing Telemetry Transport (MQTT) messages per minute.

You need to configure an alert to detect which devices have an anomalous MQTT message send rate.

What should you do?

Answer options

• A. Create an Azure IoT hub and an IoT alert that has the following settings: • Condition: C2D message deliveries completed • Threshold: Static • Threshold value: 15 • Aggregation granularity: 5 minutes
• B. Create an Azure IoT hub and an IoT alert that has the following settings: • Condition: C2D message deliveries completed • Threshold: Static • Operator: Greater than • Aggregation type: Average • Threshold value: 30
• C. Enable Azure Defender for IoT and create a custom rule that has the following settings: • Custom Alert: Number of device to cloud messages (MQTT protocol) is not in allowed range • Minimal Threshold: 30 • Maximum Threshold: 60 • Time Window Size: 00:05:00
• D. Enable Azure Defender for IoT and create a custom rule that has the following settings: • Custom Alert: Number of device to cloud messages (MQTT protocol) is not in allowed range • Minimal Threshold: 20 • Maximum Threshold: 30 • Time Window Size: 00:05:00

Correct answer: D

Explanation

The correct answer is D because it sets a minimal threshold of 20 and a maximum threshold of 30, which is appropriate since each device sends 5 messages per minute, making 20 messages the expected minimum for four devices. Options A and B are incorrect as their thresholds do not align with the expected message rate, and option C sets thresholds that are too high for the scenario.