Ospf Graceful Restart Commands; Nsf Restart-Interval - NETGEAR M6100 Series Reference Manual

OSPF Graceful Restart Commands

The OSPF protocol can be configured to participate in the checkpointing service, so that
these protocols can execute a graceful restart" when the management unit fails. In a graceful
restart, the hardware to continues forwarding IPv4 packets using OSPF routes while a
backup switch takes over management unit responsibility
Graceful restart uses the concept of helpful neighbors. A fully adjacent router enters helper
mode when it receives a link state announcement (LSA) from the restarting management unit
indicating its intention of performing a graceful restart. In helper mode, a switch continues to
advertise to the rest of the network that they have full adjacencies with the restarting router,
thereby avoiding announcement of a topology change and the potential for flooding of LSAs
and shortest-path-first (SPF) runs (which determine OSPF routes). Helpful neighbors
continue to forward packets through the restarting router. The restarting router relearns the
network topology from its helpful neighbors.
Graceful restart can be enabled for either planned or unplanned restarts, or both. A planned
restart is initiated by the operator through the initiate failover command. The
operator may initiate a failover in order to take the management unit out of service (for
example, to address a partial hardware failure), to correct faulty system behavior which
cannot be corrected through less severe management actions, or other reasons. An
unplanned restart is an unexpected failover caused by a fatal hardware failure of the
management unit or a software hang or crash on the management unit.
nsf
Use this command to enable the OSPF graceful restart functionality on an interface. To
disable graceful restart, use the no form of the command.
Default Disabled
Format
nsf [ietf] [planned-only]
Modes OSPF Router Configuration
Parameter Description
ietf This keyword is accepted but not required.
planned-only This optional keyword indicates that OSPF should only perform a graceful restart when the restart is
planned (that is, when the restart is a result of the initiate failover command).
no nsf
Use this command to disable graceful restart for all restarts.

nsf restart-interval

Use this command to configure the number of seconds that the restarting router asks its
neighbors to wait before exiting helper mode. This is referred to as the grace period. The
restarting router includes the grace period in its grace LSAs. For planned restarts (using the
M6100 Series Switches
Routing Commands
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