Configuration manual

• grace period — the length of time the graceful restart process can last before OSPF terminates it.
• helper-reject neighbors — the router ID of each restart router that does not receive assistance from
the configured router.
• mode — the situation or situations that trigger a graceful restart.
• role — the role or roles the configured router can perform.
NOTE: By default, OSPFv2 graceful restart is disabled.
To enable and configure OSPFv2 graceful restart, use the following commands.
1. Enable OSPFv2 graceful-restart globally and set the grace period.
CONFIG-ROUTEROSPF- id mode
graceful-restart grace-period seconds
The seconds range is from 40 and 3000.
This setting is the time that an OSPFv2 router’s neighbors advertises it as fully adjacent, regardless of
the synchronization state, during a graceful restart. OSPFv2 terminates this process when the grace
period ends.
2. Enter the Router ID of the OSPFv2 helper router from which the router does not accept graceful
restart assistance.
CONFIG-ROUTEROSPF- id mode
graceful-restart helper-reject router-id
• Planned-only — the OSPFv2 router supports graceful-restart for planned restarts only. A planned
restart is when you manually enter a fail-over command to force the primary RPM over to the
secondary RPM. During a planned restart, OSPF sends out a Grace LSA before the system
switches over to the secondary RPM. OSPF also is notified that a planned restart is happening.
• Unplanned-only — the OSPFv2 router supports graceful-restart for only unplanned restarts.
During an unplanned restart, OSPF sends out a Grace LSA after the secondary RPM comes online.
By default, OSPFv2 supports both planned and unplanned restarts. Selecting one or the other mode
restricts OSPFv2 to the single selected mode.
3. Configure the graceful restart role or roles that this OSPFv2 router performs.
CONFIG-ROUTEROSPF- id mode
graceful-restart role [helper-only | restart-only]
The system supports the following options:
• Helper-only: the OSPFv2 router supports graceful-restart only as a helper router.
• Restart-only: the OSPFv2 router supports graceful-restart only during unplanned restarts.
By default, OSPFv2 supports both restarting and helper roles. Selecting one or the other role restricts
OSPFv2 to the single selected role.
To disable OSPFv2 graceful-restart after you have enabled it, use the no graceful-restart grace-
period
command in CONFIG-ROUTEROSPF- id mode. The command returns OSPF graceful-restart to
its default state.
Open Shortest Path First (OSPFv2 and OSPFv3)
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