Header layouts

Header content and message layouts were designed to be flexible and to support different use cases by enabling or disabling individual fields within the headers. While this flexibility makes it possible to support many different use cases with Pub/Sub, the number of possible header field combinations also increases the effort needed for the implementation and verification. On the other hand, within a given application domain or for different use cases some configurations might be more appropriate than others.

Custom header layout configurations (also called the “Flexible” header layout) can be used but they should be limited to applications that do not fall into the use cases for the layouts.

The header layout can be configured on a publisher or subscriber, as shown in the following screenshot.

The following header layouts are supported. The header layout names are derived from the OPC UA specification, part 14, annex A.