25. Irregular area Tunnel tunnel in OSPF configuration experiment
1. Experimental topology
After OSPF is configured as shown in the topology, at this time, because area1 is separated between area2 and area0, R5 in area2 does not have routes that can reach area3, area0 and area1. For this reason, we set up a Tunnel tunnel on R3 and R4, and then announce the Tunnel tunnel into area0.
2. Experimental configuration
R1 configurations
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 configuration
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 configuration
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 configuration
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 configuration
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. Configure OSPF multi-process redistribution
R1 and R5 do not have a route to each other. We modify R3 and R4 as follows
R3 configuration
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 configuration
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
