Data Item Description (DID): System/Subsystem Design Description (SSDD)

3. DESCRIPTION/PURPOSE OF THE SSDD
3.1 The System/Subsystem Design Description (SSDD) describes the architectural (conceptual) design of the system or subsystem which is the subject of the SSDD. The SSDD also may contain a description of system/subsystem external behaviour (how the system/subsystem will behave, from a user's point of view, in meeting its requirements, to the extent that the design defines behavior more detailed than, and consistent with, system requirements, and ignoring internal implementation). The SSDD may be supplemented by Interface Design Descriptions (IDDs) (see PPA-ME04-001133) for descriptions of design decisions relating to external interfaces. The SSDD may be supplemented by Database Design Descriptions (DBDDs) (see PPA-ME04-001134), for externally input databases, externally output databases, and databases internal to the system/subsystem that are not to be engineered as configuration items.