第一步：
配置接口與啓用OSPF協議
配置如下：
R1
interface Loopback0
ip address 1.1.1.1 255.255.255.0
interface FastEthernet0/0
ip address 10.1.1.1 255.255.255.0
router ospf 1
network 1.1.1.0 0.0.0.255 area 0
network 10.1.1.0 0.0.0.255 area 0
R2
interface Loopback0
ip address 2.2.2.2 255.255.255.0
interface FastEthernet0/0
ip address 10.1.1.2 255.255.255.0
interface FastEthernet1/0
ip address 10.1.2.1 255.255.255.0
router ospf 1
network 2.2.2.0 0.0.0.255 area 1
network 10.1.1.0 0.0.0.255 area 0
network 10.1.2.0 0.0.0.255 area 1
R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0
interface FastEthernet0/0
ip address 10.1.3.1 255.255.255.0
interface FastEthernet1/0
ip address 10.1.2.2 255.255.255.0
router ospf 1
network 3.3.3.0 0.0.0.255 area 1
network 10.1.2.0 0.0.0.255 area 1
network 10.1.3.0 0.0.0.255 area 2
R4
interface Loopback0
ip address 4.4.4.4 255.255.255.0
interface FastEthernet0/0
ip address 10.1.3.2 255.255.255.0
router ospf 1
network 4.4.4.0 0.0.0.255 area 2
network 10.1.3.0 0.0.0.255 area 2
第二步
查看路由表：
R1
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/2] via 10.1.1.2, 00:17:01, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O IA 3.3.3.3 [110/3] via 10.1.1.2, 00:14:50, FastEthernet0/0
10.0.0.0/24 is subnetted, 2 subnets
O IA 10.1.2.0 [110/2] via 10.1.1.2, 00:17:08, FastEthernet0/0
C 10.1.1.0 is directly connected, FastEthernet0/0
可以看到，它學到了area 1 中的路由條目，但學不到area2的路由條目。
原因是什麼呢？
大家先想想。後面我會介紹到的。
R2
R2#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/2] via 10.1.1.1, 00:20:55, FastEthernet0/0
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/2] via 10.1.2.2, 00:18:45, FastEthernet1/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.1.2.0 is directly connected, FastEthernet1/0
C 10.1.1.0 is directly connected, FastEthernet0/0
還是沒有R4的路由
R3
R3#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O IA 1.1.1.1 [110/3] via 10.1.2.1, 00:21:51, FastEthernet1/0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/2] via 10.1.2.1, 00:23:51, FastEthernet1/0
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/2] via 10.1.3.2, 00:21:51, FastEthernet0/0
10.0.0.0/24 is subnetted, 3 subnets
C 10.1.3.0 is directly connected, FastEthernet0/0
C 10.1.2.0 is directly connected, FastEthernet1/0
O IA 10.1.1.0 [110/2] via 10.1.2.1, 00:21:51, FastEthernet1/0
R4
R4#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
4.0.0.0/24 is subnetted, 1 subnets
C 4.4.4.0 is directly connected, Loopback0
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.3.0 is directly connected, FastEthernet0/0
可以看到，R4上除了直連的路由以外是沒有別的遠程路由條目的。
第三步
我們來做 tunnel
也是在R2與R3之間做
配置如下：
R2
R2(config)#interface tunnel 0
R2(config-if)#ip address 192.168.1.1 255.255.255.0
R2(config-if)#tunnel source f1/0-------（源地址）
R2(config-if)#tunnel destination 10.1.2.2-----------（目標地址）
R2(config-if)#exit
R2(config)#router ospf 1
R2(config-router)#network 192.168.1.0 255.255.255.0 area 0
R3
R3(config)#interface tunnel 0
R3(config-if)#ip address 192.168.1.2 255.255.255.0
R3(config-if)#tunnel source f1/0 -------本端接口
R3(config-if)#tunnel destination 10.1.2.1------對端接口
R3(config-if)#exit
R3(config)#router ospf 1
R3(config-router)#network 192.168.1.0 255.255.255.0 area----啓用OSPF，且area爲0
第四
查看路由表
R1
R1#show ip rou
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/2] via 10.1.1.2, 00:07:53, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O IA 3.3.3.3 [110/3] via 10.1.1.2, 00:07:53, FastEthernet0/0
4.0.0.0/32 is subnetted, 1 subnets
O IA 4.4.4.4 [110/11114] via 10.1.1.2, 00:07:53, FastEthernet0/0
10.0.0.0/24 is subnetted, 3 subnets
O IA 10.1.3.0 [110/11113] via 10.1.1.2, 00:07:53, FastEthernet0/0
O IA 10.1.2.0 [110/2] via 10.1.1.2, 00:07:54, FastEthernet0/0
C 10.1.1.0 is directly connected, FastEthernet0/0
O 192.168.1.0/24 [110/11112] via 10.1.1.2, 00:07:54, FastEthernet0/0
R1#
R2
R4#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF , IA
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O IA 1.1.1.1 [110/11114] via 10.1.3.1, 00:08:35, FastEthernet0/0
2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/3] via 10.1.3.1, 00:08:44, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O IA 3.3.3.3 [110/2] via 10.1.3.1, 00:08:44, FastEthernet0/0
4.0.0.0/24 is subnetted, 1 subnets
C 4.4.4.0 is directly connected, Loopback0
10.0.0.0/24 is subnetted, 3 subnets
C 10.1.3.0 is directly connected, FastEthernet0/0
O IA 10.1.2.0 [110/2] via 10.1.3.1, 00:08:44, FastEthernet0/0
O IA 10.1.1.0 [110/11113] via 10.1.3.1, 00:08:35, FastEthernet0/0
O IA 192.168.1.0/24 [110/11112] via 10.1.3.1, 00:08:44, FastEthernet0/0
R4#
實驗完成！
陳濱