Message Service Handler
The MSH is an entity that is able to generate or process messages that conform to the ebMS specification, and which act in at least one of the two ebMS roles: Sender and Receiver.
In terms of SOAP processing, an MSH is either a SOAP processor or a chain of SOAP processors. In either case, an MSH has to be able to understand the eb:Messaging header (qualified with the ebMS namespace).
Definition from https://ec.europa.eu/cefdigital/wiki/display/CEFDIGITAL/CEF+Glossary
