What aspect does the external interface focus on?

The external interface primarily emphasizes the interactions that occur outside of the proposed solution. This includes how the system communicates with external entities such as users, other systems, or hardware. Understanding these interactions is crucial for ensuring that the solution is designed to effectively integrate with other systems and meet user needs.

In a requirements analysis context, focusing on external interfaces allows analysts to identify key requirements for how the system should behave in relation to its environment. This perspective ensures that the solution is not only functional within its internal framework but also capable of handling the necessary communication channels and data exchanges with external systems or users that it will interact with.

Recognizing the importance of these interactions helps in defining clear interfaces and communication protocols, which are essential for the successful integration and operation of the system as a whole.