H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IPv4 Routing
H3C S7500E Series Ethernet Switches Chapter 3 OSPF Configuration
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3.10 Troubleshooting OSPF Configuration
3.10.1 No OSPF Neighbor Relationship Established
I. Symptom
No OSPF neighbor relationship can be established.
II. 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), network type. If the network type is broadcast or NBMA, at least
one interface must have a router priority higher than 0.
III. 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 router priority higher than 0.
3.10.2 Incorrect Routing Information
I. Symptom
OSPF cannot find routes to other areas.
II. 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.
III. 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.