Dell Networking 7048, Reference Manual

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1268
OSPFv3 Commands
Syntax
nsf [ ietf ] [ planned-only ]
no nsf [ ietf ]
ietf — This keyword is used to distinguish the IETF standard
implementation of graceful restart from other implementations. Since the
IETF implementation is the only one supported, this keyword is optional.
planned-only — This keyword indicates that OSPF should only perform a
graceful restart when the restart is planned (i.e., when the restart is a result of
the initiate failover command).
Default Configuration
Graceful restart is disabled by default
Command Mode
Router OSPFv3 Configuration mode
User Guidelines
Graceful restart works in concert with nonstop forwarding to enable the
hardware to continue forwarding IPv6 packets using OSPFv3 routes while a
backup unit takes over management unit responsibility. When OSPF
executes a graceful restart, it informs its neighbors that the OSPF control
plane is restarting, but that it will be back shortly. Helpful neighbors continue
to advertise to the rest of the network that they have full adjacencies with the
restarting router, avoiding announcement of a topology change and
everything that goes with that (i.e., flooding of LSAs, SPF runs). Helpful
neighbors continue to forward packets through the restarting router. The
restarting router relearns the network topology from its helpful neighbors.
This implementation of graceful restart restarting router behavior is only
useful with a router stack. Graceful restart does not work on a standalone,
single-unit router.
nsf helper
Use the nsf-helper to allow OSPF to act as a helpful neighbor for a restarting
router. Use the no form of this command to prevent OSPF from acting as a
helpful neighbor.
2CSPC4.X7000-SWUM204.book Page 1268 Friday, March 15, 2013 8:22 AM