Huawei Quidway S3500 Series Operation Manual page 217

Operation Manual - Routing Protocol
Quidway S3500 Series Ethernet Switches
interfaces for two routers are in DROther state, the peer state machine for 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.
Execute the display ospf peer command to view peers.
Execute the display ospf interface command to view OSPF information in the
interface.
Check whether the physical connections and the lower level protocol operate
normally. You can execute the ping command to test. If the local router cannot
ping the peer router, it indicates that faults have occurred to the physical link and
the lower level protocol.
If the physical link and the lower layer protocol are normal, please check the OSPF
parameters configured on the interface. The parameters should be the same
parameters configured on the router adjacent to the interface. The same area ID
should be used, and the networks and the masks should also be consistent. (The
p2p or virtually linked segment can have different segments and masks.)
Ensure that the dead timer on the same interface is at least four times the value of
the hello timer.
If the network type is NBMA, the peer must be manually specified, using the peer
ip-address command.
If the network type is broadcast or NBMA, there must be at least one interface with
a priority greater than zero.
If an area is set as the STUB area, to which the routers are connected. The area
on these routers must be also set as the STUB area.
The same interface type should be adopted for the neighboring routers.
If more than two areas are configured, at least one area should be configured as
the backbone area (that is to say, the area ID is 0).
Ensure the backbone area to connect with all the areas.
The virtual links cannot pass through the STUB area.
Troubleshooting globally: If OSPF cannot discover the remote routes yet in the case
that the above steps are correctly performed, proceed to check the following
configurations.
If more than two areas are configured on a router, at least one area should be
configured as the backbone area.
As shown in the following figure: RTA and RTD are configured to belong to only one
area, whereas RTB (area0 and area1) and RTC (area1 and area 2) are configured to
belong to two areas. In which, RTB also belongs to area0, which is compliant with the
requirement. However, none of the areas to which RTC belongs is area0. Therefore, a
virtual link should be set up between RTC and RTB. Ensure that area2 and area0
(backbone area) is connected.
Huawei Technologies Proprietary
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Chapter 4 OSPF Configuration