1、实验拓扑

按拓扑所示配置好OSPF后，此时由于area2与area0之间隔着area1,此时area2中的R5并没有路由可达area3、area0、area1。为此我们在R3、R4上建立一条Tunnel隧道，然后将Tunnel隧道通告进area0即可。

2、实验配置

R1配置

interface Loopback0

 ip address 1.1.1.1 255.255.255.0

interface Serial0/0

 ip address 12.1.1.1 255.255.255.0

router ospf 110

 router-id 1.1.1.1

 network 1.1.1.0 0.0.0.255 area 3

 network 12.1.1.0 0.0.0.255 area 3

R2配置

interface Loopback0

 ip address 2.2.2.2 255.255.255.0

interface Serial0/0

 ip address 12.1.1.2 255.255.255.0

interface Serial0/1

 ip address 23.1.1.2 255.255.255.0

router ospf 110

 router-id 2.2.2.2

 network 2.2.2.0 0.0.0.255 area 0

 network 12.1.1.0 0.0.0.255 area 3

 network 23.1.1.0 0.0.0.255 area 0

R3配置

interface Loopback0

 ip address 3.3.3.3 255.255.255.0

interface Serial0/0

 ip address 34.1.1.3 255.255.255.0

interface Serial0/1

 ip address 23.1.1.3 255.255.255.0

router ospf 110

 router-id 3.3.3.3

 network 3.3.3.0 0.0.0.255 area 0

 network 23.1.1.0 0.0.0.255 area 0

 network 34.1.1.0 0.0.0.255 area 1

R4配置

interface Loopback0

 ip address 4.4.4.4 255.255.255.0

interface Serial0/0

 ip address 34.1.1.4 255.255.255.0

interface Serial0/1

 ip address 45.1.1.4 255.255.255.0

router ospf 110

 router-id 4.4.4.4

 log-adjacency-changes

 network 4.4.4.0 0.0.0.255 area 1

 network 34.1.1.0 0.0.0.255 area 1

 network 45.1.1.0 0.0.0.255 area 2

R5配置

interface Loopback0

 ip address 5.5.5.5 255.255.255.0

interface Serial0/1

 ip address 45.1.1.5 255.255.255.0

router ospf 110

 router-id 5.5.5.5

 log-adjacency-changes

 network 5.5.5.0 0.0.0.255 area 2

 network 45.1.1.0 0.0.0.255 area 2

3、配置OSPF多进程重分布

此时R1和R5都没有彼此的路由。我们将R3、R4上做如下修改

R3配置

interface Tunnel3

 ip address 10.1.1.3 255.255.255.0

 tunnel source 34.1.1.3

 tunnel destination 34.1.1.4

router ospf 110

 network 10.1.1.0 0.0.0.255 area 0

R4配置

interface Tunnel4

 ip address 10.1.1.4 255.255.255.0

 tunnel source 34.1.1.4

 tunnel destination 34.1.1.3

router ospf 110

 network 10.1.1.0 0.0.0.255 area 0