System engineering analyses the requirements the customer has issued for the system, then derives, generates, controls and maintains the requirement set for the lower-level elements, covering the design constraints and operating constraints on them and the functionality, performance and verification parameters needed to satisfy the customer's requirements. It keeps the requirements consistent at system level, at the lower levels and between levels, checks each requirement against the characteristics of a well-formed requirement set out in clause 8 of ECSS-E-ST-10-06, and records a justification for every lower-level requirement in a requirements justification file.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.