Crime Prevention Through Environmental Design (CPTED)

Intrusion Sensing, Alarm Communications, Alarm Assessment (e.g. Cameras), and Entry Control.

Barriers (anything hardened between your critical assets and potential intruders), Locks, Dispensible barriers, fences, etc.

Interruption of adversary using: Communication to Response Force (e.g. Safety Officers, Police, etc.), Deployment of Response Force, and neutralization of the threat.