Mean Time Between Failures (MTBF)

Device Model	Conditions	Mean Time Between Failures
8820-40C	front-to-back airflow 2 power supplies AC/DC (1+1 redundancy) 6 fans (supporting one fan fail)	225,486 hrs @ 25ºC
8820-40C	back-to-front airflow 2 power supplies AC/DC (1+1 redundancy) 6 fans (supporting one fan fail)	198,718 hrs @ 25ºC
8820-80C	front-to-back airflow 4 power supplies AC/DC (2+2 redundancy) 4 fans (supporting one fan fail)	153,251 hrs @ 25ºC
8820-80C	back-to-front airflow 4 power supplies AC/DC (2+2 redundancy) 4 fans (supporting one fan fail)	129,304 hrs @ 25ºC