Message Producer
The Message Producer is an entity that interacts with a Sending MSH (i.e. an MSH in the Sending role) to initiate the sending of a user message.
Some examples are:
An application.
A queuing system.
Another SOAP processor.
But not another MSH!
The Producer is always an MSH endpoint.
Definition from https://ec.europa.eu/cefdigital/wiki/display/CEFDIGITAL/CEF+Glossary
