Dell S4048–ON Configuration Manual page 594

Enabling OSPFv2 Graceful Restart
Graceful restart is enabled for the global OSPF process.
The Dell Networking implementation of OSPFv2 graceful restart enables you to specify:
• 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]
Dell Networking OS 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.
NOTE: The Helper mode is enabled by default on the device. To enable the restart mode also on the device, you must
configure the grace period using the graceful-restart grace-period command. After you enable restart mode
the router advertises the neighbor as fully adjacent during a restart.
For more information about OSPF graceful restart, refer to the Dell Networking OS Command Line Reference Guide.
594
Open Shortest Path First (OSPFv2 and OSPFv3)