Open Shortest Path First (OSPFv2 and OSPFv3) | 731Enable OSPFv3 graceful restartGraceful Restart for OSPFv3 is supported only on platform et. Refer to Graceful Restart on page 700for more information on the feature.By default, OSPFv3 graceful restart is disabled and functions only in a helper role to help restartingneighbor routers in their graceful restarts when it receives a Grace LSA.To enable OSPFv3 graceful restart, you must enter the ipv6 router ospf process-id command to enterOSPFv3 configuration mode and then configure a grace period using the graceful-restart grace-periodcommand. The grace period is the length of time that OSPFv3 neighbors continue to advertise therestarting router as though it is fully adjacent. When graceful restart is enabled (restarting role), an OSPFv3restarting 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 with the ipv6 ospf graceful-restart helper-rejectcommand, you reconfigure OSPFv3 graceful restart to function in a “restarting-only” role. OSPFv3 doesnot participate in the graceful restart of a neighbor. (Note that you enter the ipv6 ospf graceful-restarthelper-reject command in Interface configuration mode.)To disable OSPFv3 graceful restart when it is enabled, enter the following command:Command Syntax Command Mode Usagegraceful-restartgrace-period secondsCONF-IPV6-ROUTER-OSPFEnable OSPFv3 graceful restart globally by setting the graceperiod (in seconds). Valid values are from 40 to 1800 seconds.ipv6 ospf graceful-restarthelper-rejectINTERFACE Configure an OSPFv3 interface to not act upon the Grace LSAsthat it receives from a restarting OSPFv3 neighbor.graceful-restart mode[planned-only |unplanned-only]CONF-IPV6-ROUTER-OSPFSpecify the operating mode and type of events that trigger agraceful restart:• Planned-only. The OSPFv3 router supports graceful restartonly for planned restarts. A planned restart is when youmanually enter a redundancy force-failover rpm command toforce the primary RPM over to the secondary RPM. During aplanned restart, OSPFv3 sends out a Grace LSA before thesystem switches over to the secondary RPM. OSPFv3 isnotified that a planned restart is happening.• Unplanned-only. The OSPFv3 router supports graceful-restartonly for unplanned restarts. During an unplanned restart,OSPFv3 sends out a Grace LSA once the secondary RPMcomes online.Default: Both planned and unplanned restarts trigger an OSPFv3graceful restart. Selecting one or the other mode restricts OSPFv3to the single selected mode.Command Syntax Command Mode Usageno graceful-restart grace-period CONF-IPV6-ROUTER-OSPFDisable OSPFv3 graceful-restart.
