OPC UA PubSub Automatic Message Mapping Recognition: Difference between revisions

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With some transport protocols, only a single message mapping is used (or, at least, OPC UA only has a standard profile with a single combination). For example, UDP and Ethernet transport protocol mappings are only used with the UADP message mapping (this is because they are meant for optimized, fast, low-level communications). Other transport protocol mappings, such as AMQP or MQTT, can be combined with different message mappings. For example, MQTT can be used either with UADP or JSON, depending on the needs of the application.
With some transport protocols, only a single message mapping is used (or, at least, OPC UA only has a standard profile with a single combination). For example, UDP and Ethernet transport protocol mappings are only used with the UADP message mapping (this is because they are meant for optimized, fast, low-level communications). Other transport protocol mappings, such as AMQP or MQTT, can be combined with different message mappings. For example, MQTT can be used either with UADP or JSON, depending on the needs of the application.
The combination of transport protocol and message mapping is described using a ''transport profile URI'', and specified for each OPC UA PubSub connection.

Revision as of 12:21, 21 March 2022

OPC UA PubSub uses different message mappings, which define how the PubSub messages are structured and encoded when put into the transport protocol as its payload. Currently, OPC UA PubSub defines two message mappings:

  • UADP (binary, defined by OPC UA)
  • JSON (textual, built upon interoperable standard)

With some transport protocols, only a single message mapping is used (or, at least, OPC UA only has a standard profile with a single combination). For example, UDP and Ethernet transport protocol mappings are only used with the UADP message mapping (this is because they are meant for optimized, fast, low-level communications). Other transport protocol mappings, such as AMQP or MQTT, can be combined with different message mappings. For example, MQTT can be used either with UADP or JSON, depending on the needs of the application.

The combination of transport protocol and message mapping is described using a transport profile URI, and specified for each OPC UA PubSub connection.

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