routera--e0------e0--routerb--s0/0-------s0/0--routerc--e0---
area 0 area1 area 4
//router a
int lo0
ip addr 1.1.1.1 255.255.255.0
int e0/0
ip addr 192.1.1.1 255.255.255.0
router ospf 64
netw 192.1.1.0 0.0.0.255 area 0
//router b
int lo0
ip addr 2.2.2.2 255.255.255.0
int e0/0
ip addr 193.1.1.2 255.255.255.0
clockrate 500000
router ospf 64
netw 192.1.1.0 0.0.0.255 area 0
netw 193.1.1.0 0.0.0.255 area 1
area 1 virtual-link 3.3.3.3
//router c
int lo0
ip addr 3.3.3.3 255.255.255.0
int e0/0
ip addr 152.1.1.1 255.255.255.0
no keepalive //禁用以太网接口上的keepalive，以使得当它不连结在某个集线器上时仍然保持UP状态
int s0/0
ip adr 193.1.1.1 255.255.255.0
router ospf 64
netw 193.1.1.0 0.0.0.255 area 1
netw 152.1.1.0 0.0.0.255 area 4
area 1 virtual-link 2.2.2.2 //定义跨越区域1到2.2.2.2的虚拟链路，其中2.2.2.2是路由器B的路由器ID
监视和测试配置：
a#show ip ospf virtual-link
virtual link ospf_VL0 to router 2.2.2.2 is up
b#show ip ospf virtual-link
virtual link ospf_VL0 to router 3.3.3.3 is up
加载中，请稍候......
加载中…