3Com Switch 8800 Configuration Guide Chapter 19 OSPF Configuration
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Change the priority of Switch B to 200
[Switch B-Vlan-interface2000] ospf dr-priority 200
On Switch A, execute the display ospf peer command to show its OSPF neighbors.
Note the priority of Switch B has changed to 200, but it is still not the DR.
Only when the current DR is offline, will the DR be changed. Shut down Switch A, and
execute the display ospf peer command on Switch D to display its neighbors. Note
that the original BDR (Switch C) becomes the DR, and Switch B is BDR now.
If all Switches on the network are removed and added back again, Switch B will be
elected as the DR (with the priority of 200), and Switch A becomes the BDR (with a
priority of 100). To switch off and restart all of the switches will bring about a new round
of DR/BDR selection.
19.4.2 Configuring OSPF Virtual Link I. Network requirements
In Figure 19-4, Area 2 and Area 0 are not directly connected. Area 1 is required to be
taken as a transit area for connecting Area 2 and Area 0. Configure a virtual link
between Switch B and Switch C in Area 1.
II. Network diagram
152.1.1.1/24
196.1.1.2/24
Switch A
1.1.1.1
Switch B
2.2.2.2 Virtual
Link
197.1.1.2/24
Area 2
Area 1
Area 0
Switch C
3.3.3.3
197.1.1.1/24
196.1.1.1/24
Figure 19-4 Network diagram for OSPF virtual link configuration