The graceful-restart t2-interval command configures a value for the T2 timer during an IS-IS GR.
The undo graceful-restart t2-interval command restores the default value of the T2 timer.
By default, the GR T2 timer is 60 seconds.
| Parameter | Description | Value |
|---|---|---|
| interval-value | Specifies the value of the T2 timer during the IS-IS GR. |
The value is an integer that ranges from 30 to 1800,
in seconds. Setting a value smaller than that of the GR T3 timer specified using the graceful-restart interval command is recommended. |
Usage Scenario
IS-IS GR can be classified into restarting GR and starting GR based on the restart type. The restarting GR is triggered by a master/slave main control board switchover or an IS-IS process restart, while the starting GR is triggered by a restart of the IS-IS-enabled router.
A GR restarter starts the T1 and T2 timers during all GRs. The value of the T1 timer indicates the longest time during which the GR restarter waits for the LSP from the GR helper. The value of the T2 timer indicates the longest time during which the system waits for the LSDB synchronization. The T2 timer is disabled after the LSDB synchronization among Level-1 or Level-2 routers ends. If LSDBs are not synchronized yet when the T2 timer expires, the GR fails.
You can run the graceful-restart t2-interval command to adjust the value of the T2 timer so that the LSDB synchronization can end before the T2 timer expires, which prevents the GR failure.
Prerequisites
The GR of the IS-IS process has been enabled using the graceful-restart command.
Precautions
If the value of the T2 timer is too small, a GR may fail. Keeping the default value is recommended. If you want to adjust it, configure a value to meet the conditions on the live network.