Dell N3200-ON EMC Networking N-Series Switches CLI Reference Guide version 6.7 - Page 1764

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. Syntax nsf [ietf] helper[planned-only] no nsf [ietf] helper • planned-only - This keyword indicates that OSPF should only help a restarting router performing a planned restart. Default Configuration OSPF may act as a helpful neighbor for both planned and unplanned restarts Command Mode Router OSPF Configuration mode User Guidelines The grace LSA announcing the graceful restart includes a restart reason. Reasons 1 (software restart) and 2 (software reload/upgrade) are considered planned restarts. Reasons 0 (unknown) and 3 (switch to redundant control processor) are considered unplanned restarts. nsf ietf helper disable is functionally equivalent to no nsf helper and is supported solely for IS CLI compatibility. Layer 3 Routing Commands 1764