AZ-900 Describe Azure architecture and services Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Azure Event Hubs

  Why it's wrong here

  Azure Event Hubs is a managed big data streaming ingestion service that accepts millions of events per second from sources like apps, devices, and microservices. It is schema-agnostic and Kafka-compatible, but it is a one-way ingest pipeline, not a device management solution. Event Hubs lacks per-device identity registry, device twins, and direct-method command capabilities, so it cannot handle remote device control or lifecycle management. In an IoT architecture, Event Hubs might sit downstream of IoT Hub for telemetry analytics, not replace it.

• ✗

  Azure Notification Hubs

  Why it's wrong here

  Azure Notification Hubs is a push notification engine for sending mobile push notifications to Android, iOS, Windows, and other platforms using APNs, FCM, and WNS. It performs device registration for push services and template-based fan-out, but it does not expose any way to interact with a device's configuration, properties, or telemetry. While it can alert users on their phones, it does not provide the secure, bidirectional device-to-cloud and cloud-to-device messaging or the device management APIs that IoT solutions require.

• ✓

  Azure IoT Hub

  Why this is correct

  Azure IoT Hub is the correct choice because it is a fully managed IoT-specific service that provides secure bidirectional communication, per-device authentication, device twins, direct methods, and automatic device management. It maintains an identity registry for every connected device, so you can connect and manage each device individually with SAS tokens or X.509 certificates. IoT Hub also ingests telemetry and routes it to downstream Azure services, while supporting cloud-to-device commands such as desired-state updates and firmware-over-the-air jobs. These IoT-native features are exactly what is needed for managing IoT devices at scale.

• ✗

  Azure Service Bus

  Why it's wrong here

  Azure Service Bus is a fully managed enterprise message broker for integrating applications through queues and topics using publish/subscribe patterns. It offers advanced features like sessions, transactions, duplicate detection, and dead-lettering, which are ideal for business messaging workflows, but it is not built for the IoT device lifecycle. Service Bus has no notion of device identity, device twin state, or per-device command responses, so it cannot manage devices or report device-specific properties. It might be used as a downstream component to connect IoT events into backend line-of-business systems, not as the device management layer.

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