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Device Connectivity Status
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Device Connectivity Status

Feature Overview

IoT Hub Device State service is responsible for monitoring the device connectivity state and triggering the device connectivity events that are pushed to the Rule Engine. As a platform user, you are able to define how to react to these events.

Supported events are:

  • Connect event - triggered when a device connects to IoT Hub. Relevant in the case of session-based transports like MQTT. It is also triggered for HTTP transport, but in this case, it will be triggered on each HTTP request;
  • Disconnect event - triggered when the device disconnects from IoT Hub. Relevant in the case of session-based transports like MQTT. It is also triggered for HTTP transport, but in this case, it will be triggered on each HTTP request;
  • Activity event - triggered when a device pushes telemetry, attribute update, or RPC command;
  • Inactivity event - triggered when a device was inactive for a certain period of time. Please note that this event may be triggered even without disconnect event from the device. Typically, means that there were no activity events triggered for a while.

Device State service is responsible for maintaining the following server-side attributes:

  • active - represents current device state, either true or false;
  • lastConnectTime - represents the last time device was connected to IoT Hub, number of milliseconds since January 1, 1970, 00:00:00 GMT;
  • lastDisconnectTime - represents the last time device was disconnected from IoT Hub, number of milliseconds since January 1, 1970, 00:00:00 GMT;
  • lastActivityTime - represents the last time device pushed telemetry, attribute update, or RPC command, number of milliseconds since January 1, 1970, 00:00:00 GMT;
  • inactivityAlarmTime - represents the last time inactivity event was triggered, number of milliseconds since January 1, 1970, 00:00:00 GMT.

Configuration

Device State service uses a global configuration parameter for inactivity timeout. This parameter is defined in thingsboard.yml (state.defaultInactivityTimeoutInSec) and by default it is set to 10 seconds. A user can overwrite this parameter for an individual device by setting the “inactivityTimeout” server-side attribute (value is set in milliseconds).

Device State service uses a global configuration parameter to detect inactivity events. This parameter is defined in thingsboard.yml (state.defaultStateCheckIntervalInSec) and by default it is set to 10 seconds.

Next steps

  • Getting started guides - These guides provide quick overview of main IoT Hub features. Designed to be completed in 15-30 minutes.