The envelope model

The envelope model should contain the information needed to complete whatever the user wants to accomplish with the message. This is the generic information, as opposed to the actual message itself, which is the subject of the next section (the section called The message model). The term envelope was chosen because of it's clarity when compared with generic vocabulary.

First and foremost, you need an identification of the parties[1] on both sides. Secondly, you need a place to store the info on business processes and a place to store the message. For a proof-of-concept, Figure 6-5 provides a model that contains enough information to be usable in simple applications.