T1/E1 LCR provides revertive and non-revertive modes; non-revertive mode is the default option. In revertive mode, the activity is switched back to the working adapter card after it has recovered from a failure. In non-revertive mode, a switch to the protection adapter card is maintained even after the working adapter card has recovered from a failure.
To prevent frequent automatic switches that result from intermittent failures, a revert-time is defined for revertive switching. The revert-time is configurable from 0 to 60 min in increments of 1 min; the default value is 5 min. In some scenarios, performance issues can occur if the revert-time is set to 0; therefore, it is recommended that the revert-time always be set to a value of 1 or higher. Any change in the revert-time value takes effect upon the next initiation of the wait-to-restore (WTR) timer. The change does not modify the duration of a WTR timer that has already been started. The WTR timer of a non-revertive switch can be assumed to be infinite.