Source: Security Magazine
How to Protect Sub-Perimeters with Advanced IP Technology
By definition, a perimeter is the outer boundary, and securing that perimeter means protecting that area. Everything has a perimeter, from a large university campus to your own personal space on that campus. Law enforcement and security personnel have predefined outer perimeters that keep people either in or out in the case of an event. But you should also look within the perimeter to criticalities that could present problems.