H3C Technologies H3C S5560 Series Switches - Manual (Page 147)

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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
To resolve the problem:
1. Use the display ospf peer command to verify neighbor information.
2. Use the display ospf interface command to verify OSPF interface information.
3. Use the display ospf lsdb command to verify the LSDB.
4. Use the display current-configuration configuration ospf command to verify area configuration. 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
routers attached are configured with the nssa command.
6. If a virtual link is configured, use the display ospf vlink command to verify the state of the virtual
link.
7. If the problem persists, contact H3C Support.