Why a single strong fence isn't a complete security strategy — and how concentrating protection into one boundary quietly creates a single point of failure.
It's tempting to believe that a tall enough fence, a strong enough gate, or a sophisticated enough main-entrance access reader is "enough" security on its own. Perimeter security relies on exactly that: a single outer boundary standing between unauthorized people and everything valuable inside. Defense-in-depth(layered security) rejects that premise entirely — it assumes any one layer can eventually be defeated, and deliberately stacks multiple independent layers so that defeating one still leaves an intruder facing several more. The difference isn't how strong any single layer is. It's what happens the moment that one layer fails.