Mypower
S4100
Troubleshooting
Maipu Confidential & Proprietary Information
Page
94
of
124
zero.
Note: Point-to-point and point to multiple point network, do
not select DR and BDR.
15.
The OSPF neighbor is
in the
Exstart/Exchange
status
How to find out the cause:
Run the show ip ospf neighbor command. The neighbor
interfaces are in the exstart status and the other end is in the
Exchange status.
Open debug ip ospf packet DD detail. The MTU parameters of
the DD packets in the two negotiation parties are different. The
prompt message is “MTU size is too large (1500)”
Use the packets less than 1500 bytes to ping the opposite
interface. Then use the packets larger than 1500 bytes to ping
the opposite interface.
Solution:
For the different MTU, modify the MTU or configure the mtu-
ignor in the interface. For the unavailable ping, find other
causes, for example, whether ACL is created to prevent the
unicast packets.
Fault 2: OSPF neighbor status is Full, but the route cannot be calculated
Possible Reasons
Judging Methods and Solutions
1.
The OSPF network
modes of the two
parties are not
matched
How to find out the cause:
When the OSPF network modes of the two parties are not
matched, the neighbor status may be full, but when the route
cannot be learned, for example, the point to point network mode
and the broadcast network mode, after the two parties are set to
the mode, the neighbor status can be full, but the routing
information cannot be calculated.
Solution:
Check whether the four types of OSPF network modes are
matched:
ip ospf network broadcast
ip ospf network non-broadcast
ip ospf network point-to-multipoint
ip ospf network point-to-point
Note: The Ethernet is in the broadcast mode by default.
2.
The advertised LSA
metric reaches the
maximum
How to find out the cause:
Show ip route ospf, no relevant routes are learned
Show ip ospf route, no routes are learned
Show ip ospf database, LSA is learned
Show LSA, find that metric is the maximum
Solution:
Change the metric of the advertised LSA
3.
Unavailable next-hop
causes that the route
cannot be calculated
How to find out the cause:
Show ip route ospf, no relevant routes are learned
Show ip ospf database, LSA is learned
Debug ip route spf, check the route calculation
Solution:
Check the network topology, ensure that the next-hop is
available and then the route can be calculated
4.
There is no route
about the forward
address
How to find out the cause:
The LSA of external route is learned
Show ip ospf route, there is no route about the forward address
Show ip route ospf, external route is not added
Solution:
Ensure that in the area of the forward address or between areas,
