architectural solution

A design-level response to a security, privacy, or compliance requirement — one that resolves the requirement through structural choices about how components, systems, or services are arranged, separated, or interconnected rather than through policy alone or through a single point-in-time control. In NIST usage, an architectural solution names and describes a particular deployment configuration — such as a specific encryption placement strategy — and then maps the key-management or other security challenges that follow from that structural choice. In policy contexts (such as the passage you quoted), organizations or regulators mandate specific architectural solutions when a security property — for example, mandatory access control or network isolation — cannot be reliably achieved through configurable settings and must instead be built in at the design level.