Help Center/ IoT Device Access/ API Reference/ MQTT or MQTTS API Reference on the Device Side/ Gateway and Child Device Management/ Gateway Responding to a Request for Updating Child Device Statuses
Updated on 2026-09-01 GMT+08:00
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Gateway Responding to a Request for Updating Child Device Statuses

Function

This API is used by the platform to respond to the request for updating child devices (for details, see Gateway Updating Child Device Status). The response is returned within 30 seconds after the platform receives the request and includes a list of updated statuses of child devices. For details about the relationship between a gateway and its child devices, see Gateways and Child Devices.

Topic

Downstream: $oc/devices/{device_id}/sys/events/down

Parameters

Parameter

Mandatory/Optional

Type

Description

object_device_id

Optional

String

Explanation:

The value is the same as that of device_id in the topic.

services

Optional

List<ServiceEvent>

Explanation:

List of services that an event is about.

ServiceEvent structure

Parameter

Mandatory/Optional

Type

Description

service_id

Mandatory

String

Explanation:

System field.

Value range:

Fixed at $sub_device_manager.

event_type

Mandatory

String

Explanation:

System field.

Value range:

Fixed at sub_device_update_status_response.

event_time

Optional

String

Explanation:

Event time. UTC time format: yyyyMMdd'T'HHmmss'Z'.

event_id

Mandatory

String

Explanation:

Event ID. The value is used to associate with the corresponding event.

paras

Mandatory

Object

Explanation:

Event parameters in JSON format.

paras structure

Parameter

Mandatory/Optional

Type

Description

successful_devices

Mandatory

List<DeviceStatus>

Explanation:

Details about the child devices that are updated.

failed_devices

Mandatory

List<Reason>

Explanation:

Cause of the failure to update the child device status.

DeviceStatus structure

Parameter

Mandatory/Optional

Type

Description

device_id

Mandatory

String

Explanation:

Device ID.

status

Optional

String

Explanation:

Indicates the device status update result.

Value range:

  • ONLINE: The device is online.
  • OFFLINE: The device is offline.

Reason structure

Parameter

Mandatory/Optional

Type

Description

device_id

Mandatory

String

Explanation:

The value is that of device_id of the corresponding device in the corresponding request.

error_code

Mandatory

String

Explanation:

Error code.

error_msg

Mandatory

String

Explanation:

Error description.

Example

Topic: $oc/devices/{device_id}/sys/events/down  
Data format:
{
   "object_device_id": "{object_device_id}",
   "services": [
    {
      "service_id": "$sub_device_manager",
      "event_type": "sub_device_update_status_response",
      "event_time": "20151212T121212Z",
      "event_id": "40cc9ab1-3579-488c-95c6-c18941c99eb4",
      "paras": {
          "successful_devices": [
          {
            "device_id": "c6b39067b0325db34663d3ef421a42f6_subdevice11",
            "status": "ONLINE"
          }
        ],
        "failed_devices": [
          {
            "device_id": "c6b39067b0325db34663d3ef421a42f6_subdevice11",
            "error_code": "XXX",
            "error_msg": "XXXX"
          }
        ]

      }
    }
  ]
}