Incorrect Routing Information - HP 4800G Series Configuration Manual

Analysis
If the physical link and lower layer protocols work well, check OSPF parameters configured on
interfaces. Two neighbors must have the same parameters, such as the area ID, network segment and
mask (a P2P or virtual link may have different network segments and masks).
Processing steps
1) Display OSPF neighbor information using the display ospf peer command.
2) Display OSPF interface information using the display ospf interface command.
3) Ping the neighbor router's IP address to check connectivity.
4) Check OSPF timers. The dead interval on an interface must be at least four times the hello interval.
5) On an NBMA network, using the peer ip-address command to specify the neighbor manually is
required.
6) On an NBMA or a broadcast network, at least one connected interface must have a DR priority
higher than 0.

Incorrect Routing Information

Symptom
OSPF cannot find routes to other areas.
Analysis
The backbone area must maintain connectivity to all other areas. If a router connects to more than one
area, at least one area must be connected to the backbone. The backbone cannot be configured as a
Stub area.
In a Stub area, all routers cannot receive external routes, and all interfaces connected to the Stub area
must belong to the Stub area.
Solution
1) Use the display ospf peer command to display neighbors.
2) Use the display ospf interface command to display OSPF interface information.
3) Use the display ospf lsdb command to display the Link State Database to check its integrity.
4) Display information about area configuration using the display current-configuration
configuration ospf command. If more than two areas are configured, at least one area is
connected to the backbone.
5) In a Stub area, all routers attached are configured with the stub command. In an NSSA area, all
interface connected to which are configured with the nssa command.
6) If a virtual link is configured, use the display ospf vlink command to check the state of the virtual
link.
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