Help Center/ IoT Device Access/ User Guide/ Rules/ Data Forwarding to Third-Party Applications/ MQTT Data Forwarding/ Overview
Updated on 2024-11-06 GMT+08:00
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Overview

The figure below shows the subscription and push process.

Push mechanism: The IoT platform pushes QoS 0 messages to users. If a user does not establish a connection or does not subscribe to the topic after the connection is established, the IoT platform will delete expired data and data that exceeds the capacity limit in rolling mode when the maximum cache duration (24 hours) or maximum cache size (1 GB) is reached or exceeded.

Subscribing to Data

  1. You can create a rule and add an MQTT message queue as the forwarding target on the console to subscribe to data. For details, see MQTT Server Configuration.
  2. Call APIs to subscribe to data. For details, see Calling APIs, Creating a Rule Triggering Condition, Creating a Rule Action, and Modifying a Rule Triggering Condition.

Format of Pushed Data

For details on the format of data pushed by the platform to applications after data subscription is created, see Data Transfer APIs.

Constraints

Description

Constraint

Supported MQTT version

3.1.1

Differences from the standard MQTT protocol
  • QoS 0 is supported.
  • Custom topics are supported.
  • Shared subscription is supported.
  • QoS 1 and QoS 2 are not supported.
  • Will and retained messages are not supported.
  • Client publishing is not supported.

Security level supported by MQTTS

TCP + TLS (TLS v1.2)

Supported cipher suites:

  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

  • TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

MQTT connection requests for an account per second

10

MQTT connections for an account

10 per access credential

Push rate of an MQTT connection

1,000 TPS

Message cache duration and size

The maximum duration is one day, and the maximum size is 1 GB. Caching is limited by either of the item. For example, if the cache duration exceeds one day, data will not be cached even if the size does not reach 1 GB.

Recommended heartbeat interval for MQTT connections

Range: 30s to 1200s; recommended: 120s

Message publishing and subscription
  • Shared subscription is supported. Clients that subscribe to the same topic consume pushed data in polling mode. Clients can subscribe to only the topics created in the forwarding rule.
  • Message publishing is not supported.

Subscriptions per subscription request

Maximum number of topics supported by an account

Topics subscribed to by an account (created during rule action creation)

100
Parent topic: MQTT Data Forwarding