You may find it necessary to deprovision devices that were previously auto-provisioned through the Device Provisioning Service.
In general, deprovisioning a device involves two steps:
1. Disenroll the device from your provisioning service, to prevent future auto-provisioning. Depending on whether you want to revoke access temporarily or permanently, you may want to either disable or delete an enrollment entry.
2. Deregister the device from your IoT Hub, to prevent future communications and data transfer. Again, you can temporarily disable or permanently delete the device's entry in the identity registry for the IoT Hub where it was provisioned.
Reference:
https://docs.microsoft.com/bs-latn-ba/azure/iot-dps/how-to-unprovision-devices
AZ-220
Number: AZ-220
Passing Score: 800
Time Limit: 120 min
File Version: 1
AZ-220
Implement the IoT solution infrastructure
Testlet 1
Case Study
This is a case study. Case studies are not timed separately. You can use as much exam time as you
would like to complete each case. However, there may be additional case studies and sections on this
exam. You must manage your time to ensure that you are able to complete all questions included on this exam
in the time provided.
To answer the questions included in a case study, you will need to reference information that is provided in the
case study. Case studies might contain exhibits and other resources that provide more information about the
scenario that is described in the case study. Each question is independent of the other question on this case
study.
At the end of this case study, a review screen will appear. This screen allows you to review your answers and
to make changes before you move to the next sections of the exam. After you begin a new section, you cannot
return to this section.
To start the case study
To display the first question on this case study, click the Next button. Use the buttons in the left pane to explore
the content of the case study before you answer the questions. Clicking these buttons displays information
such as business requirements, existing environment, and problem statements. If the case study has an All
Information tab, note that the information displayed is identical to the information displayed on the subsequent
tabs. When you are ready to answer a question, click the Question button to return to the question.
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 BYclause.
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 levelproperty 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.
Implement the IoT solution infrastructure
Question Set 2

Explanation
Routes are declared in the $edgeHub desired properties.
Reference:
https://docs.microsoft.com/en-us/azure/iot-edge/module-composition

Explanation
Device twins store device-related information that:
Device and back ends can use to synchronize device conditions and configuration.
The solution back end can use to query and target long-running operations.
Desired properties. Used along with reported properties to synchronize device configuration or conditions. The solution back end can set desired properties, and the device app can read them. The device app can also receive notifications of changes in the desired properties.
Reference:
https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-device-twins
Topic 1, ADatum
Case Study
This is a case study. Case studies are not timed separately. You can use as much exam time as you would like to complete each case. However, there may be additional case studies and sections on this exam. You must manage your time to ensure that you are able to complete all questions included on this exam in the time provided.
To answer the questions included in a case study, you will need to reference information that is provided in the case study. Case studies might contain exhibits and other resources that provide more information about the scenario that is described in the case study. Each question is independent of the other question on this case study.
At the end of this case study, a review screen will appear. This screen allows you to review your answers and to make changes before you move to the next sections of the exam. After you begin a new section, you cannot return to this section.
To start the case study
To display the first question on this case study, click the button. Use the buttons in the left pane to explore the content of the case study before you answer the questions. Clicking these buttons displays information such as business requirements, existing environment, and problem statements. If the case study has an All Information tab, note that the information displayed is identical to the information displayed on the subsequent tabs. When you are ready to answer a question, click the button to return to the question.
Requirements. Planned Changes
ADatum is developing an Azure IoT solution to monitor environmental conditions. The IoT solution consists of hardware devices and cloud services. All the devices will communicate directly to Azure IoT Hub.
The hardware devices will be deployed to the branch offices and will collect data about various environmental conditions such as temperature, humidity, air quality, and noise level. The devices will be wired by using Power over Ethernet (PoE) connections.
ADatum is developing the solution in the following three phases: proof of value (POV), pilot, and production.
Requirements. POV Requirements
The POV phase will demonstrate that a technical solution is viable. During this phase, 100 devices will be deployed to the main office and Azure Stream Analytics will be connected to an IoT hub to generate real-time alerts. Stream Analytics will perform the following processing:
* Calculate the median rate of the telemetry across the entire devices that exceed the median rate by a factor of 4.
* Compare the current telemetry to the specified thresholds and issue alerts when telemetry values are out of range.
* Ensure that all message content during this phase is human readable to simplify debugging.
Requirements. Pilot Requirements
During the pilot phase, devices will be deployed to 10 offices. Each office will have up to 1,000 devices.
During this phase, you will add Azure Time Series Insights in parallel to Stream Analytics to support real-time graphs and queries in a dashboard web app.
The pilot deployment must minimize operating costs.
Requirements. Production Requirements
The production phase will include all the offices.
The production deployment will have one IoT hub in each Azure region. Devices must connect to the IoT hub in their region.
The production phase must meet the following requirements:
* Ensure that the IoT solution can support performance and scale targets.
* Ensure that the IoT solution support up to 1,000 devices per office.
* Minimize operating costs of the IoT solution.
Requirements. Technical Requirements
Datum identifies the following requirements for the planned IoT solution:
* The solution must generate real-time alerts when a fire condition is detected in an office. All the devices in that office must trigger an audible alarm siren within 10 seconds of the alert.
* A dashboard UI must display alerts and the system status in real time and must allow device operators to make adjustments to the system.
* Each device will send hourly updates to IoT Hub. Condition alerts will be sent immediately.
* Multiple types of devices will collect telemetry that has different schemas.
* IoT Hub must perform message routing based on the message body.
* Direct methods must be used for cloud-to-device communication.
* Reports must be provided monthly, quarterly, and annually.
* Stored data queries must be as efficient as possible.
* The device message size will be under 4 KB.
* Development effort must be minimized.
Requirements. Throttle and Quotas
The relevant throttles and quotas for various IoT Hub tiers are shown in the following table.

Requirements. IoT Hub Routing
You plan to implement IoT Hub routing during the POV phase as shown in the following exhibit.

Explanation
The TPM simulator's Registration ID and the Endorsement key, are used when you create an individual enrollment for your device.
Reference:
https://docs.microsoft.com/en-us/azure/iot-edge/how-to-auto-provision-simulated-device-linux

The IoT Hub resource logs connections category emits operations and errors having to do with device connections. The following screenshot shows a diagnostic setting to route these logs to a Log Analytics workspace:

Note: Azure Monitor: Route connection events to logs:
IoT hub continuously emits resource logs for several categories of operations. To collect this log data, though, you need to create a diagnostic setting to route it to a destination where it can be analyzed or archived. One such destination is Azure Monitor Logs via a Log Analytics workspace, where you can analyze the data using Kusto queries.
Reference:
https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-troubleshoot-connectivity