This is the hold time, in seconds, this co-routed tunnel waits after recovering before automatically reverting to active, assuming reversion is enabled, applying to the whole bidirectional circuit as a unit. An admin sizes this to avoid the entire two-way circuit flapping back and forth if the primary path is intermittently unstable. For example, a 180-second reversion timeout on a co-routed circuit means the primary path must stay healthy in both directions continuously for three minutes before the circuit reverts.