Huawei Quidway S5600 Series Operation Manual page 344

Operation Manual – Routing Protocol
Quidway S5600 Series Ethernet Switches-Release 1510
Local fault removal: Firstly, check whether the protocol works normally between two
directly connected routers. The normal sign is that the peer state machine between the
two routers reaches the FULL state. Note: On a broadcast or NBMA network, if the
interfaces between two routers are in DROther state, the peer state machine between
the two routers are in 2-way state, 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 through the peer router, it 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 is performed, 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 Figure 4-5, RTA and RTD are configured to belong to only one area,
whereas RTB (Area 0 and Area 1) and RTC (Area 1 and Area 2) are configured to
belong to two areas. RTB also belongs to area 0, which meets the requirement.
However, none of the areas of RTC is Area 0. Therefore, a virtual link should be set up
between RTC and RTB. Ensure that Area 2 and Area 0 (backbone area) are
interconnected.
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Chapter 4 OSPF Configuration