HP 6125XLG - Configuring IS-IS NSR

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• T2 timer—Specifies the LSDB synchronization interval. Each LSDB has a T2 timer. The Level-1-2 router
has two T2 timers: a Level-1 timer and a Level-2 timer. If the LSDBs have not synchronized before the
two timers expire, the GR process fails.
• T3 timer—Specifies the GR interval. The GR interval is set as the holdtime in hello PDUs. Within the
interval, the neighbors maintain their adjacency with the GR restarter. If the GR process has not
completed within the holdtime, the neighbors tear down the neighbor relationship and the GR
process fails.
IMPORTANT:
IS-IS GR and IS-IS NSR are mutually exclusive. Do not configure them at the same time.
To configure GR on the GR restarter:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enable IS-IS and
enter IS-IS view.
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
N/A
3. Enable IS-IS GR.
graceful-restart
By default, the GR capability for IS-IS is
disabled.
4. (Optional.) Suppress
the SA bit during
restart.
graceful-restart suppress-sa
By default, the SA bit is not suppressed.
By enabling the GR restarter to suppress the
Suppress-Advertisement (SA) bit in the hello
PDUs, the neighbors will still advertise their
adjacency with the GR restarter.
5. (Optional.) Configure
the T1 timer.
graceful-restart t1 seconds count
count
By default, the T1 timer is 3 seconds and can
expire 10 times.
6. (Optional.) Configure
the T2 timer.
graceful-restart t2 seconds By default, the T2 timer is 60 seconds.
7. (Optional.) Configure
the T3 timer.
graceful-restart t3 seconds By default, the T2 timer is 300 seconds.
Configuring IS-IS NSR
After an active/standby switchover, the GR restarter obtains routing information from its neighbors, and
the IS-IS process must learn all the routes. If the network topology changes during the switchover,
removed routes cannot be updated to the device, which can result in blackhole routes.
NSR solves the problem by backing up IS-IS link state information from the active process to the standby
process. After an active/standby switchover, NSR can complete link state recovery and route
regeneration without requiring the cooperation of other devices.
IMPORTANT:
IS-IS NSR and IS-IS GR are mutually exclusive. Do not configure them at the same time.
To configure IS-IS NSR: