Dell S6100 Configuration Manual page 627

By default, OSPFv3 graceful restart is disabled and functions only in a helper role to help restarting neighbor routers in their graceful
restarts when it receives a Grace LSA.
To enable OSPFv3 graceful restart, enter the ipv6 router ospf process-id command to enter OSPFv3 configuration mode. Then
configure a grace period using the graceful-restart grace-period command. The grace period is the time that the OSPFv3
neighbors continue to advertise the restarting router as though it is fully adjacent. When you enable graceful restart (restarting role), an
OSPFv3 restarting expects its OSPFv3 neighbors to help when it restarts by not advertising the broken link.
When you enable the helper-reject role on an interface using the ipv6 ospf graceful-restart helper-reject command, you
reconfigure OSPFv3 graceful restart to function in a restarting-only role. OSPFv3 does not participate in the graceful restart of a neighbor.
NOTE: Enter the ipv6 ospf graceful-restart helper-reject command in Interface configuration mode.
• Enable OSPFv3 graceful restart globally by setting the grace period (in seconds).
CONF-IPV6-ROUTER-OSPF mode
graceful-restart grace-period seconds
The valid values are from 40 to 1800 seconds.
• Configure an OSPFv3 interface to not act on the Grace LSAs that it receives from a restarting OSPFv3 neighbor.
INTERFACE mode
ipv6 ospf graceful-restart helper-reject
• Specify the operating mode and type of events that trigger a graceful restart.
CONF-IPV6-ROUTER-OSPF mode
graceful-restart mode [planned-only | unplanned-only]
• Planned-only: the OSPFv3 router supports graceful restart only for planned restarts. A planned restart is when you manually
enter a redundancy force-failover rpm command to force the primary RPM over to the secondary RPM. During a
planned restart, OSPFv3 sends out a Grace LSA before the system switches over to the secondary RPM. OSPFv3 is notified that a
planned restart is happening.
• Unplanned-only: the OSPFv3 router supports graceful-restart only for unplanned restarts. During an unplanned restart,
OSPFv3 sends out a Grace LSA once the secondary RPM comes online.
The default is both planned and unplanned restarts trigger an OSPFv3 graceful restart. Selecting one or the other mode restricts
OSPFv3 to the single selected mode.
• Disable OSPFv3 graceful-restart.
CONF-IPV6-ROUTER-OSPF mode
no graceful-restart grace-period
Displaying Graceful Restart
To display information on the use and configuration of OSPFv3 graceful restart, enter any of the following commands.
• Display the graceful-restart configuration for OSPFv2 and OSPFv3 (shown in the following example).
EXEC Privilege mode
show run ospf
• Display the Type-11 Grace LSAs sent and received on an OSPFv3 router (shown in the following example).
EXEC Privilege mode
show ipv6 ospf database grace-lsa
• Display the currently configured OSPFv3 parameters for graceful restart (shown in the following example).
EXEC Privilege mode
Open Shortest Path First (OSPFv2 and OSPFv3) 627