H3C S7500 Series Operation Manual page 348

Operation Manual – Routing Protocol
H3C S7500 Series Ethernet Switches
instead of FULL state. The peer state machine between DR/BDR and all the other
routers is in FULL state.
Use the display ospf peer command to view peers.
Use the display ospf interface command to view the OSPF information on an
interface.
Check whether the physical connection is correct and the lower layer protocol
operates normally. You can use the ping command to test. If the local router
cannot ping the peer router, this indicates that faults exist on the physical link and
the lower level protocol.
If the physical connection and the lower layer protocol are normal, check the
OSPF parameters configured on the interface. Verify that these parameter
configurations are consistent with those on the peer interface. The area IDs must
be the same, and the network segments and the masks must also be consistent
(p2p or virtually linked segments can have different segments and masks).
Ensure that the dead timer value is at least four times of the hello timer value on
the same interface.
If the network type is NBMA, you must use the peer ip-address command to
manually specify a peer.
If the network type is broadcast or NBMA, ensure that there is at least one
interface with a priority greater than zero.
If an area is set to a stub area, ensure that the area is set to a stub area for all the
routers connected to this area.
Ensure that the interface types of two neighboring routers are consistent.
If two or more areas are configured, ensure that at least one area is configured
as the backbone area; that is, the area ID of an area is 0.
Ensure that the backbone area is connected to all the other areas.
Ensure that no virtual link passes through a stub area.
Global fault removal:
If OSPF still cannot discover the remote routes after the above procedure, check the
following configurations:
If two or more areas are configured on a router, at least one area should be
configured to be connected to the backbone area.
As shown in
and area 1) and RTC (area 1 and area 2) belong to two areas. One of the areas of
RTB is area 0 (the backbone area). However, neither areas of RTC is area 0.
Therefore, a virtual link should be set up between RTC and RTB to ensure that Area 2
and Area 0 are interconnected.
Figure 4-5, RTA and RTD belong to only one area, whereas RTB (area 0
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Chapter 4 OSPF Configuration