Channel reliability

Circuit reliability (also time availability) (CiR) is the percentage of time an electronic circuit was available for use in a specified period of scheduled availability. Circuit reliability is given by where T _o is the circuit total outage time, T_s is the circuit total scheduled time, and T _a is the circuit total available time. $T_{s}=T_{a}+T_{o}$

In addition, circuit reliability is the expected lifespan of operation of a functioning system under nominal conditions.