Information Technology Reference
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Adjacent with neighbor 192.168.31.33 (Designated Router)
Adjacent with neighbor 192.168.31.22 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Use the show ip ospf neighbor command to view information about the other routers in
the OSPF area.
Step 3.
Notice that R3 is the DR and R2 is the BDR:
R1# show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
192.168.31.22 1 FULL/BDR 00:00:35 192.168.1.2 FastEthernet0/0
192.168.31.33 1 FULL/DR 00:00:30 192.168.1.3 FastEthernet0/0
Task 7: Use the OSPF Priority to Determine the DR and BDR
Use the ip ospf priority interface command to change the OSPF priority of the R1 router
to 255, which is the highest possible priority.
Step 1.
R1(config)# interface fastEthernet0/0
R1(config-if)# ip ospf priority 255
R1(config-if)# end
Use the ip ospf priority interface command to change the OSPF priority of the R3 router
to 100.
Step 2.
R3(config)# interface fastEthernet0/0
R3(config-if)# ip ospf priority 100
R3(config-if)# end
Use the ip ospf priority interface command to change the OSPF priority of the R2 router
to 0.
Step 3.
A priority of 0 causes the router to be ineligible to participate in an OSPF election and
become a DR or BDR:
R2(config)# interface fastEthernet0/0
R2(config-if)# ip ospf priority 0
R2(config-if)# end
Shut down and reenable the FastEthernet 0/0 interfaces to force an OSPF election.
Step 4.
The FastEthernet 0/0 interfaces of each of the routers can be shut down and reenabled to
force an OSPF election. Shut down the FastEthernet 0/0 interface on each of the three
routers. Notice that as the interfaces are shut down, the OSPF adjacencies are lost:
R1(config)# interface fastethernet0/0
R1(config-if)# shutdown
%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administra
tively down
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed
state to down
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