Configuring Ospf Virtual Link - 3Com 5500-EI PWR Install Manual

On Switch A, run the display ospf peer command to display its OSPF peers. Note that Switch A has
three peers.
The state of each peer is full, which means that adjacency is established between Switch A and each
peer. Switch A and Switch C must establish adjacencies with all the switches on the network so that
they can serve as the DR and BDR respectively on the network. Switch A is DR, while Switch C is BDR
on the network. All the other neighbors are DR others (This means that they are neither DRs nor BDRs).
# Change the priority of Switch B to 200.
<SwitchB> system-view
[SwitchB] interface Vlan-interface 1
[SwitchB-Vlan-interface1] ospf dr-priority 200
On Switch A, use the display ospf peer command to display its OSPF neighbors. Note that the priority
of Switch B has been changed to 200, but it is still not a DR.
The current DR is changed only when it is offline. Shut down Switch A, and use 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 becomes BDR now.
If all Ethernet Switches on the network are removed from and then added to the network again, Switch
B will be elected as the DR (with a priority of 200), and Switch A will be the BDR (with a priority of 100).
Shutting down and restarting all the switches will bring about a new round of DR/BDR election on the
network.

Configuring OSPF Virtual Link

Network requirements
Devices in the network run OSPF to realize interconnection. The network is split into three areas: one
backbone area and two non-backbone areas (Area 1 and Area 2). Area 2 has no direct connection to
the backbone, and it has to reach the backbone through Area 1. The customer hopes that Area 2 can
interconnect with other two areas.
Based on the customer requirements and networking environment, use a virtual link to connect Area 2
to the backbone area.
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