concentric physical model (perimeter → facility → data hall → cage/rack) with escalating MFA at each boundary
4 zonesobserved
| Value kind | observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range. |
|---|---|
| As of | 2026 |
| Source | NIST / DCK physical-security guidance · The Four Layers of Physical Data Center Security: perimeter, facility, server room and cabinet |
| Review | checking…review by 2026-11-23 · standard cadence |
| Recorded changes | last 2026-06-29 |
| Claim id | concentric-physical-model-perimeter-facility |
Where the guide uses it
← Full numbers register — every date-stamped figure in the guide, with revision history.