Users Guide

To enable OSPFv3 graceful restart, enter the ipv6 router ospf command to enter OSPFv3 conguration
mode and then congure a grace period using the graceful-restart grace-period command. The grace period
is the length of time that OSPFv3 neighbors continue to advertise the restarting router as though it is fully
adjacent. When graceful restart is enabled (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 with the ipv6 ospf graceful-restart helper-reject
command, you recongure OSPFv3 graceful restart to function in a “restarting-only” role. In a “restarting-
only” role, OSPFv3 does not participate in the graceful restart of a neighbor.
graceful-restart mode
Specify the type of events that trigger an OSPFv3 graceful restart.
S4820T
Syntax
graceful-restart mode {planned-only | unplanned-only}
To disable graceful restart mode, enter no graceful-restart mode.
Parameters
planned-only (OPTIONAL) Enter the keywords planned-only to indicate graceful restart is
supported in a planned restart condition only.
unplanned-only (OPTIONAL) Enter the keywords unplanned-only to indicate graceful restart is
supported in an unplanned restart condition only.
Defaults OSPFv3 graceful restart supports both planned and unplanned failures.
Command Modes ROUTER OSPFv3
Command History
This guide is platform-specic. For command information about other platforms, refer to the relevant Dell
Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.1.(0.0) Introduced on the S4810 and Z9000.
8.4.2.2 Introduced on the E-Series TeraScale.
8.3.19.0 Introduced on the S4820T.
Usage Information
OSPFv3 graceful restart supports planned-only and/or unplanned-only restarts. The default is support for
both planned and unplanned restarts.
• A planned restart occurs when you enter the redundancy force-failover rpm command to
force the primary RPM to switch to the backup RPM. During a planned restart, OSPF sends out a
Type-11 Grace LSA before the system switches over to the backup RPM.
• An unplanned restart occurs when an unplanned event causes the active RPM to switch to the backup
RPM, such as when an active process crashes, the active RPM is removed, or a power failure happens.
During an unplanned restart, OSPF sends out a Grace LSA when the backup RPM comes online.
By default, both planned and unplanned restarts trigger an OSPFv3 graceful restart. Selecting one or the
other mode restricts OSPFv3 to the single selected mode.
Open Shortest Path First (OSPFv2 and OSPFv3)
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