Defines what is external to the application.
Is the conceptual interface between the ‘internal’ software and the ‘external’ user world.
Acts as a ‘membrane’ through which data processed by transactions (EIS, EOs, and EQs) passes into and out of the application
Encloses the logical data maintained by the application (ILFs).
Assists in identifying the logical data referenced by but not maintained within the application (EIFs)
Is dependent on the user’s external business view of the application. It is independent of technical or implementation considerations.