The current text describing DefaultDatagramPublisherId in PublishSubscribeType definition does not make it clear where is this default applied and how. It may look like that it is to be used every time when a publisherId is not available or is null; but according to Matthias Damm, it is only meant for configuration tools.

The reference to the article defining the PublisherId does not help much - it only talks about the default type of PublisherId for datagram protocols.

The place where it truly gets used appears to be the ReserveIds method (and maybe elsewhere too), but that is practically impossible to infer, because the name of the method argument differs (does not have "datagram" in it), and the method is probably expected to use the default only when the TransportProfileUri is for the datagram protocol, which isn't described either.

Matthias Damm suggested to expand the "configuration behaviors" chapter with these, and other, improvements.