The graceful-restart no-impact-holdtime command configures the holdtime of an IS-IS neighbor to remain unchanged after IS-IS GR is enabled.
The undo graceful-restart no-impact-holdtime command cancels the configuration.
By default, after IS-IS GR is enabled, the holdtime of an IS-IS neighbor is automatically changed to 60s if it is smaller than 60s, and the holdtime of an IS-IS neighbor is kept unchanged if it is equal to or greater than 60s.
Usage Scenario
If IS-IS GR is enabled on a router, the holdtimes of this router's neighbors are automatically changed to 60s if they are smaller than 60s, and the holdtimes of this router's neighbors are kept unchanged if they are equal to or greater than 60s. If a router is faulty in non-GR scenarios, its neighbors need to take 60 seconds to detect the fault. A large number of packets may be discarded within the 60 seconds.
To resolve this problem, run the graceful-restart no-impact-holdtime command to configure the holdtimes of the neighbors to remain unchanged after IS-IS GR is enabled. After you run this command, the router can still fast detect neighbor status, implementing rapid network convergence.
Prerequisites
You have run the graceful-restart (IS-IS) command in the IS-IS view.