Users Guide

Layer 3 Routing Commands 1676
Passive Interfaces
The passive interface feature is used to disable sending OSPF routing updates
on an interface. An OSPF adjacency will not be formed on such an interface.
On a passive interface, subnet prefixes for IP addresses configured on the
interface will continue to be advertised as stub networks.
Graceful Restart
The Dell EMC Networking implementation of OSPFv2 supports graceful
restart as specified in RFC 3623. Graceful restart works in concert with Dell
EMC Networking nonstop forwarding to enable the hardware to continue
forwarding IPv4 packets using OSPFv2 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.
Dell EMC Networking implements both the restarting router and helpful
neighbor features described in RFC 3623.
area default-cost (Router OSPF)
Use the area default-cost command in Router OSPF Configuration mode to
configure the advertised default cost for the stub area. Use the no form of the
command to return the cost to the default value.
Syntax
area area-id default-cost integer
no area area-id default-cost
• area-id — Identifies the OSPF stub area to configure. (Range: IP address
or decimal from 0-4294967295)
• integer — The default cost for the stub area. (Range: 1–16777215)