CSSE begins with identification of user scenarios and user-interface prototypes to develop an operational model. The operational model includes a first draft of user documentation. It provides necessary information for all subsequent development. Essential requirements are represented by integrated data, process, and control models. Infrastructure requirements are explicitly modeled, including performance, reliability, systems management, and external interfaces.
Allocation typically results in additional requirements for interfaces.
The result is a complete set of functional and technical requirements for each program or process. This may be used for detail design or code generation. With the architecture model in hand, performance requirements are verified. Simulation is used to identify bottlenecks and loading conditions that would violate performance requirements. The architecture is revised accordingly.