Dell S4820T Configuration Manual page 706

This setting is the amount of time OSPF has available to change its interface authentication type.
When you configure the auth-change-wait-time, OSPF sends out only the old authentication
scheme until the wait timer expires. After the wait timer expires, OSPF sends only the new
authentication scheme. However, the new authentication scheme does not take effect immediately
after the authentication change wait timer expires; OSPF accepts both the old as well as new
authentication schemes for a time period that is equal to two times the configured authentication
change wait timer. After this time period, OSPF accepts only the new authentication scheme.
This transmission stops when the period ends.
The default is 0 seconds.
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.
706
Open Shortest Path First (OSPFv2 and OSPFv3)