Constraint
A constraint represents a factor that prevents or obstructs the realization of goals.

In contrast to a requirement, a constraint does not prescribe some intended functionality of the system to be realized, but imposes a restriction on the way it operates or may be realized. This may be a restriction on the implementation of the system (e.g., specific technology that is to be used), a restriction on the implementation process (e.g., time or budget constraints), or a restriction on the functioning of the system (e.g., legal constraints).

: Constraint (architecture_autodiagram)
Figure 82 : Constraint (architecture_autodiagram)
ConstraintRequirement