One advantage that the BPMN Business Process diagram offers over traditional business process diagrams is the ability to model message flows. Traditional business process diagrams enable the modeling of sequential process flows:- from starting events to ending results. In an eCommerce environment, however, people send messages to one another as part of the process flow. These messages drive the depiction and understanding of business-to-business and business-to-consumer processes. The BPMN Business Process diagram enables you to model message passing using the Message Flow line. The Message Flow lines drive the depiction and understanding of eCommerce processes.
Messages are sent between two different departments or organizations. System Architect enforces this rule by mandating that a Message Flow line be drawn across a poolor a lane for it to connect between two processes.
You cannot connect a Message Flow line between two processes in the same lane.
