Affected specification/section: Part 81, Table 93 (PubSubCommunicationFlowConfigurationType), description of the Variables TransportProfileUri and HeaderLayoutUri.

Problem:

Both Variables are optional but specify a mandatory default value if the Variable is not implemented.
This enforces an implementation to either use the default value or implement the variable (i.e. expose in the information model) with at least 1 entry (which represents the configured value) in the corresponding SelectionList.

This is (1) inconsistent, since none of the other variables define a default value and (2) requires an implementation to expose these Variables with at least a single entry (if != default), even if the user does not want to make any modification options available for Clients.

Proposal:

Remove the definition of the default value for these 2 Variables.