100 
Figure 24 Network diagram 
 
 
Configuration procedure 
1.  Configure IP addresses for interfaces. (Details not shown.) 
2.  Enable OSPF: 
# Configure Router A.  
<RouterA> system-view 
[RouterA] router id 11.2.1.2 
[RouterA] ospf 
[RouterA-ospf-1] area 0 
[RouterA-ospf-1-area-0.0.0.0] network 11.2.1.0 0.0.0.255 
[RouterA-ospf-1-area-0.0.0.0] quit 
[RouterA-ospf-1] quit 
# Configure Router B. 
<RouterB> system-view 
[RouterB] router id 11.2.1.1 
[RouterB] ospf 
[RouterB-ospf-1] area 0 
[RouterB-ospf-1-area-0.0.0.0] network 11.2.1.0 0.0.0.255 
[RouterB-ospf-1-area-0.0.0.0] quit 
[RouterB-ospf-1] quit 
# Configure Router C. 
<RouterC> system-view 
[RouterC] router id 11.1.1.2 
[RouterC] ospf 
[RouterC-ospf-1] area 0 
[RouterC-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255 
[RouterC-ospf-1-area-0.0.0.0] network 10.2.1.0 0.0.0.255 
[RouterC-ospf-1-area-0.0.0.0] quit 
[RouterC-ospf-1] quit 
Router A
Router B
Router D
Router E
Router C
Eth1/1
10.1.1.1/24
Eth1/1
10.1.1.2/24
Eth1/1
10.2.1.2/24
Eth1/3
10.2.1.1/24
Eth1/2
11.1.1.2/24
Eth1/2
11.1.1.1/24
EBGP
AS 200
AS 100
Eth1/1
11.2.1.1/24
Eth1/1
11.2.1.2/24
Eth1/2
10.3.1.1/24
Eth1/2
10.4.1.1/24