For Signal Fail (SF) recovery situations, you can use the wtr-time command to configure the Wait-To-Restore (WTR) timer on the RPL owner to prevent frequent operation of the protection switching due to the detection of intermittent signal failures. When recovering from a Signal Failure, the WTR timer must be long enough to allow the recovering network to become stable.
This WTR timer is activated on the RPL Owner Node. When the relevant delay timer expires, the RPL owner initiates the reversion process by transmitting an R-APS (NR, RB) message. The WTR timer is deactivated when any higher-priority request preempts this timer. The WTR timers may be started and stopped. A request to start running the WTR timer does not restart the WTR timer. A request to stop the WTR timer stops the WTR timer and resets its value. The clear erp wtr-time command can be used to stop the WTR timer. While the WTR timer is running, the WTR running signal is continuously generated. After the WTR timer expires, the WTR running signal is stopped, and the WTR Expires signal is generated. When the WTR timer is stopped by the clear erp wtr-time command, the WTR Expires signal is not generated.
When configured, the RPL owner waits until the timer expires before transmitting the R-APS (NR, RB) message to initiate the reversion process. While the timer is in effect, the WTR running signal is continuously generated. You can configure the WTR timer in 1 minute increments from 1 to 12 minutes; the default value is 5 minutes.
The following example configures a WTR time of one minute.
device# configure terminal device(config)# erp 1 device(config-erp-1)# wtr-time 1
Use the no wrt-time command to clear the configuration in ERP configuration mode, restoring it to the default value.
Use the global clear erp wtr-time command to clear the WTR timer for a specific ERP instance, as in the following example for instance 1.
device# clear erp wtr-time 1