Orchestrations subscribe and publish messages to the MessageBox. Orchestrations can also be bound to Receive and Send Ports in different ways, which logically reflects as different kinds of subscriptions. As an extension to that, Orchestrations can also be configured to route messages between Orchestration instances, so that more than one Orchestration can participate in the execution chain, but they also go through the MessageBox. The only time the MessageBox is not involved is when you use the Call Orchestration shape to initiate execution of another Orchestration.
Ports in Orchestrations describe how the Orchestration will communicate with the MessageBox and the direction of that communication, that is, inbound or outbound. Ports are based on Port Types. The Port Type describes the communication pattern (one-way or request-response) and MessageType communicated. A Port Type can have a one-to-many relationship with ports. Ports can...