- , , , , -. , tier, -. , - , (, tier 4), , , tier 4.
tier - Uptime Institute
, Uptime Institute, , .
TIA EIA 942 Uptime Institute
Uptime Institute TIA EIA 942, 2005 . TIA EIA 942 , : , , , , , , , . , .
N ( need) . (, N+1 , ), (, N*2 ).
tier 1
. - 60- 70- . . . , ().
, ( N)
28,8
99,671%
- tier 2
- 2- . - -. , . .
, ( N+1)
22,0
99,749%