Operation Manual – IPv4 Routing
H3C S3610&S5510 Series Ethernet Switches
Chapter 4 IS-IS Configuration
4-35
The Graceful Restart interval on a router is used as the holdtime in the IS-IS Hello
PDUs so that its neighbors can maintain the adjacencies within the interval after the
router restarts.
By setting the SA (Suppress-Advertisement) bit in the hello PDUs sent by the GR
Restarter, its neighbors will not advertise adjacencies within the specified period until
the completion of LSDB synchronization between the GR Restarter and its neighbors.
This feature helps to effectively avoid blackhole routes due to the sending or receiving
of LSPs across the restart.
Note:
A device can act as both the GR Restarter and GR Helper at the same time.
Follow these steps to configure GR on the GR Restarter and GR Helper respectively:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Enable IS-IS, and
enter IS-IS view
isis
[
process-id
]
[
vpn-instance
vpn-instance-name
]
Required
Disabled by default
Enable the GR
capability for IS-IS
graceful-restart
Required
Disabled by default
Set the Graceful
Restart interval
graceful-restart interval
timer
Required
300 seconds by default
Configure to set
the SA bit during
restart
graceful-restart
suppress-sa
Optional
By default, the SA bit is not
set.
4.7 Displaying and Maintaining IS-IS
To do…
Use the command…
Remarks
Display brief IS-IS
information
display isis brief
[
process-id
|
vpn-instance
vpn-instance-name
]
Available in any view
Display information
about IS-IS enabled
interfaces
display isis interface
[
verbose
] [
process-id
|
vpn-instance
vpn-instance-name
Available in any view
Display IS-IS license
information
display isis
license
Available in any view