What should you include in the recommendation?

Topic 1, Contoso

Case Study

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Existing Environment. Current State of Development

Contoso produces a set of Bluetooth sensors that read the temperature and humidity. The sensors connect to IoT gateway devices that relay the data.

All the IoT gateway devices connect to an Azure IoT hub named iothub1.

Existing Environment. Device Twin

You plan to implement device twins by using the following JSON sample.

Existing Environment. Azure Stream Analytics

Each room will have between three to five sensors that will generate readings that are sent to a single IoT gateway device. The IoT gateway device will forward all the readings to iothub1 at intervals of between 10 and 60 seconds.

You plan to use a gateway pattern so that each IoT gateway device will have its own IoT Hub device identity.

You draft the following query, which is missing the GROUP BY clause.

SELECT

AVG(temperature),

System.TimeStamp() AS AsaTime

FROM

Iothub

You plan to use a 30-second period to calculate the average temperature reading of the sensors.

You plan to minimize latency between the condition reported by the sensors and the corresponding alert issued by the Stream Analytics job.

Existing Environment. Device Messages

The IoT gateway devices will send messages that contain the following JSON data whenever the temperature exceeds a specified threshold.

The level property will be used to route the messages to an Azure Service Bus queue endpoint named criticalep.

Existing Environment. Issues

You discover connectivity issues between the IoT gateway devices and iothub1, which cause IoT devices to lose connectivity and messages.

Requirements. Planning Changes

Contoso plans to make the following changes:

– Use Stream Analytics to process and view data.

– Use Azure Time Series Insights to visualize data.

– Implement a system to sync device statuses and required settings.

– Add extra information to messages by using message enrichment.

– Create a notification system to send an alert if a condition exceeds a specified threshold.

– Implement a system to identify what causes the intermittent connection issues and lost messages.

Requirements. Technical Requirements

Contoso must meet the following requirements:

– Use the built-in functions of IoT Hub whenever possible.

– Minimize hardware and software costs whenever possible.

– Minimize administrative effort to provision devices at scale.

– Implement a system to trace message flow to and from iothub1.

– Minimize the amount of custom coding required to implement the planned changes.

– Prevent read operations from being negatively affected when you implement additional services.

You need to recommend a solution to keep device properties synced to IoT Hub. The solution must minimize data loss caused by the connectivity issues.

What should you include in the recommendation?
A . Azure Event Grid
B . a cloud-to-device message
C . loT Hub device twins
D . the loT Hub direct method

View Answer

Answer: C

Explanation:

Scenario: You discover connectivity issues between the IoT gateway devices and iothub1, which cause IoT devices to lose connectivity and messages.

To synchronize state information between a device and an IoT hub, you use device twins. A device twin is a JSON document, associated with a specific device, and stored by IoT Hub in the cloud where you can query them. A device twin contains desired properties, reported properties, and tags.

Reference: https://docs.microsoft.com/en-us/azure/iot-hub/tutorial-device-twins