The goal of the Information System/Data Flow Diagram is to capture the main components of an Information System, how data moves within the system, user-interaction points, and the Authorization Boundary. Think of this diagram as conceptual rather than technical, multiple systems can be abstracted together, and there's no need to detail every network connection. The Authorization Boundary describes the limits of the Information System which pieces are currently being assessed. Information Systems often depend on other Information Systems, but those other Information Systems will be assessed independently, and their risk factored into the current Information System.