Dell PowerConnect 8100 CLI Reference Guide - Page 1318

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. 1318 OSPFv3 Commands