Virtual Link Topology

1. Service-side environment deployment

1. R1 router:

Configure the IP address information of each interface, configure the fixed IP address of the loop network card, and configure the OSPF protocol information.

conf t
int f0/0
ip add 192.168.10.1 255.255.255.0
no shut
int f0/1
ip add 192.168.20.1 255.255.255.0
no shut
ex
int lo 0                                
ip add 1.1.1.1 255.255.255.255        
no shut
ex
router ospf 1                                             
router-id 1.1.1.1                   
network 192.168.10.0 0.0.0.255 area 2  
network 192.168.20.0 0.0.0.255 area 2  

2. R2 Router

Configure the IP address information of each interface, configure the fixed IP address of the loop network card, configure the OSPF protocol information, and create virtual links.

conf t
int f0/0
ip add 192.168.20.2 255.255.255.0
no shut
int f0/1
ip add 192.168.30.1 255.255.255.0
no shut
ex
int lo 0                                
ip add 2.2.2.2 255.255.255.255          
no shut
ex
router ospf 1                                
router-id 2.2.2.2                       
network 192.168.20.0 0.0.0.255 area 2   
network 192.168.30.0 0.0.0.255 area 1   
ex
router ospf 1                           
area 1 virtual-link 3.3.3.3           

3. R3 router:

Configure the IP address information of each interface, configure the fixed IP address of the loop network card, configure the OSPF protocol information, and create virtual links.

conf t
int f0/0
ip add 192.168.30.2 255.255.255.0
no shut
ex
int f0/1
ip add 192.168.40.1 255.255.255.0
no shut
int lo 0
ip add 3.3.3.3 255.255.255.255
no shut
ex
router ospf 1                        
router-id 3.3.3.3                     
network 192.168.30.0 0.0.0.255 area 1 
network 192.168.40.0 0.0.0.255 area 0 
ex
router ospf 1                       
area 1 virtual-link 2.2.2.2  

4. R4 router:

Configure the IP address information of each interface, configure the fixed IP address of the loop network card, and configure the OSPF protocol information.

conf t
int f0/0
ip add 192.168.40.2 255.255.255.0
no shut
int f0/1
ip add 192.168.50.1 255.255.255.0
no shut
ex
int lo 0
ip add 4.4.4.4 255.255.255.255
no shut
ex
router ospf 1                         
router-id 4.4.4.4                
network 192.168.40.0 0.0.0.255 area 0  
network 192.168.50.0 0.0.0.255 area 0 

II. Client Environment Deployment

1. PC1 Configuration IP Address and Gateway Information

2. PC2 Configuration IP Address and Gateway Information

3. Verify the Interoperability of the Whole Network

PC1 can communicate with PC2 via virtual link. The experiment is successful.