Azure IoT Hub

Azure IoT Hub is a fully managed service that enables reliable and secure bidirectional communication between millions of Internet of Things (IoT) devices and a cloud solution. It acts as a central message hub for IoT applications, providing device-to-cloud and cloud-to-device communication, device management, and security.

Key Features and Concepts

Device Connectivity

IoT Hub supports various protocols for device connectivity, including:

  • MQTT: A lightweight messaging protocol ideal for constrained devices.
  • AMQP: Advanced Message Queuing Protocol, offering reliable, ordered message delivery.
  • HTTPS: For devices that can only support web protocols.

Message Routing

IoT Hub allows you to route device-to-cloud messages to various backend services based on message properties and content. This enables advanced data processing and analytics.


// Example of message routing configuration (conceptual)
{
  "routes": [
    {
      "condition": "temperature > 30",
      "endpoint": "azure_blob_storage_endpoint"
    },
    {
      "condition": "severity = 'critical'",
      "endpoint": "azure_service_bus_queue_endpoint"
    },
    {
      "condition": "true", // Default route
      "endpoint": "azure_cosmos_db_endpoint"
    }
  ]
}

Device Identity Registry

The device identity registry stores information about each device that is allowed to connect to IoT Hub. This includes device ID, authentication keys, and desired state properties.

Device Twins and Module Twins

Device twins and module twins are JSON documents representing the state of a device or module. They consist of:

  • Desired Properties: Set by the cloud application, intended to be synchronized with the device.
  • Reported Properties: Reported by the device, reflecting its current state.
  • Tags: Metadata applied to twins for organization and querying.

Tip:

Use device twins to manage device configurations and observe device status from the cloud.

Device Management

IoT Hub provides capabilities for device management, including:

  • Device Provisioning: Securely onboarding new devices.
  • Device Twin Management: Updating desired properties and querying reported properties.
  • Direct Methods: Invoking commands on devices.
  • Jobs: Scheduling and executing jobs across multiple devices.

Security

Security is paramount in IoT. IoT Hub offers robust security features:

  • Device Authentication: Supports symmetric keys and X.509 certificates.
  • Transport Layer Security (TLS): Encrypts communication between devices and IoT Hub.
  • Per-device identity: Each device has its own identity and credentials.

Important:

Always use secure authentication methods and TLS to protect your IoT devices and data.

Getting Started with IoT Hub

To start using Azure IoT Hub, you'll typically:

  1. Create an IoT Hub instance in the Azure portal.
  2. Register your devices in the device identity registry.
  3. Connect your devices to IoT Hub using supported SDKs.
  4. Send telemetry data from devices to the cloud and receive commands from the cloud.

For detailed guidance, please refer to the official Azure IoT Hub documentation.