444 CHAPTER 29: CONFIGURING OSPF
Configuring an OSPF Virtual Link Area 4 is not directly connected with area 0 in the following diagram. Area 1 serves as the transit area to connect area 4 and area 0. Configure a virtual link between Router B and Router C.

Figure 149 Networking diagram of configuring OSPF virtual link

To configure an OSPF virtual link:
1Configure Router A:
[RouterA] interface ethernet 0
[RouterA-Ethernet0] ip address 192.1.1.1 255.255.255.0
[RouterA-Ethernet0] quit
[RouterA] router id 1.1.1.1
[RouterA] ospf enable
[RouterA-ospf] interface ethernet 0
[RouterA-Ethernet0] ospf enable area 0
2Configure Router B:
[RouterB] interface ethernet 0
[RouterB-Ethernet0] ip address 192.1.1.2 255.255.255.0
[RouterB-Ethernet0] interface serial 0
[RouterB-Serial0] ip address 193.1.1.2 255.255.255.0
[RouterB-Serial0] quit
[RouterB] router id 2.2.2.2
[RouterB] ospf enable
[RouterB-ospf] interface ethernet 0
[RouterB-Ethernet0] ospf enable area 0
[RouterB-Ethernet0] interface serial 0
[RouterB-Serial0] ospf enable area 1
[RouterB-Serial0] quit
[RouterB] ospf
[RouterB-ospf] Vlink peer-id 3.3.3.3 transit-area 1
3Configure Router C:
[RouterC] interface ethernet 0
[RouterC-Ethernet0] ip address 152.1.1.1 255.255.255.0
[RouterC-Ethernet0] interface serial 0
[RouterC-Serial0] ip address 193.1.1.1 255.255.255.0
[RouterC-Serial0] quit
E0 192.1.1.1/24
E0 152.1.1.1/24
E0 192.1.1. 2/24
Router B
Virtual
Link
S0 193.1.1. 2/24
Area 2
Area 1
Area 0
Router C
3.3.3.3
Router A
2.2.2.2
1.1.1.1
S0 193.1.1. 1/24