The EIGRP IPv6 NSF/GR feature supports three types of timers: the signal timer, the converge timer, and the graceful-restart
Configure the signal timer to adjust the maximum time of the initial restart period. The restarting device sends hello packets
with the restart-signal (RS) bit set. If the restarting device has not learned about any neighbor or any Nonstop Forwarding
(NSF)-aware neighbor or has not received all updates from neighbors when the timer expires, the Routing Information Base (RIB)
is notified for convergence. The default value for the signal timer is 20 seconds. The
signal command is used to configure the signal timer.
Configure the converge timer to adjust the maximum time that a restarting device waits for the end-of-table (EOT) indications
from all neighbors. The default value for the converge timer is 120 seconds. The
converge command is used to configure the converge timer.
Configure the graceful-restart purge-time timer to adjust the maximum waiting time to receive the convergent signal from a
restarting device. The graceful-restart purge-time timer is used when the NSF-aware peer does not receive the EOT indication
from the restarting neighbor. When the graceful-restart purge-time timer expires, the Enhanced Interior Gateway Routing Protocol
(EIGRP) peer scans the topology table for stale routes from the restarting neighbor and changes the stale routes to active.
This process allows EIGRP peers to find alternate routes instead of waiting during a long switchover operation. The default
value for the graceful-restart purge-time timer is 240 seconds. The
purge-time command is used to configure the graceful-restart purge-time timer.