Multi-Area OSPF Configuration Example with Verification

* Topology:

* Configuration:

R1 configuration:

interface Loopback0

ip address 1.1.1.1 255.255.255.255

!

interface GigabitEthernet0/0/0

ip address 10.1.1.1 255.255.255.0

duplex auto

speed auto

!

interface GigabitEthernet0/0/1

no ip address

duplex auto

speed auto

shutdown

!

interface Vlan1

no ip address

shutdown

!

router ospf 1

log-adjacency-changes

network 10.1.1.1 0.0.0.0 area 1

network 1.1.1.1 0.0.0.0 area 1

!

ip classless

R2 configuration:



interface Loopback0

ip address 2.2.2.2 255.255.255.255

!

interface GigabitEthernet0/0/0

ip address 10.1.1.2 255.255.255.0

duplex auto

speed auto

!

interface GigabitEthernet0/0/1

ip address 10.1.2.1 255.255.255.0

duplex auto

speed auto

!

interface Vlan1

no ip address

shutdown

!

router ospf 1

log-adjacency-changes

network 2.2.2.2 0.0.0.0 area 0

network 10.1.2.0 0.0.0.255 area 0

network 10.1.1.0 0.0.0.255 area 1

R3 Configuration:


interface Loopback0

ip address 3.3.3.3 255.255.255.255

ip ospf 1 area 0

!

interface GigabitEthernet0/0

ip address 10.1.3.1 255.255.255.0

ip ospf 1 area 2

duplex auto

speed auto

!

interface GigabitEthernet0/1

ip address 10.1.2.2 255.255.255.0

ip ospf 1 area 0

duplex auto

speed auto

!

interface Vlan1

no ip address

shutdown

!

router ospf 1

log-adjacency-changes

R4 Configuration:


interface Loopback0

ip address 4.4.4.4 255.255.255.255

!

interface GigabitEthernet0/0

ip address 10.1.3.2 255.255.255.0

duplex auto

speed auto


router ospf 1

log-adjacency-changes

network 0.0.0.0 255.255.255.255 area 2

Verifications:

R1#sh ip rou

R1#sh ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, 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

C 1.1.1.1/32 is directly connected, Loopback0

2.0.0.0/32 is subnetted, 1 subnets

O IA 2.2.2.2/32 [110/2] via 10.1.1.2, 00:23:39, GigabitEthernet0/0/0

3.0.0.0/32 is subnetted, 1 subnets

O IA 3.3.3.3/32 [110/3] via 10.1.1.2, 00:23:39, GigabitEthernet0/0/0

4.0.0.0/32 is subnetted, 1 subnets

O IA 4.4.4.4/32 [110/4] via 10.1.1.2, 00:23:39, GigabitEthernet0/0/0

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

C 10.1.1.0/24 is directly connected, GigabitEthernet0/0/0

L 10.1.1.1/32 is directly connected, GigabitEthernet0/0/0

O IA 10.1.2.0/24 [110/2] via 10.1.1.2, 00:23:39, GigabitEthernet0/0/0

O IA 10.1.3.0/24 [110/3] via 10.1.1.2, 00:23:39, GigabitEthernet0/0/0

---------------------------------------

R2 ip route:

R2#sh ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, 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 1.1.1.1/32 [110/2] via 10.1.1.1, 00:31:51, GigabitEthernet0/0/0

2.0.0.0/32 is subnetted, 1 subnets

C 2.2.2.2/32 is directly connected, Loopback0

3.0.0.0/32 is subnetted, 1 subnets

O 3.3.3.3/32 [110/2] via 10.1.2.2, 00:31:46, GigabitEthernet0/0/1

4.0.0.0/32 is subnetted, 1 subnets

O IA 4.4.4.4/32 [110/3] via 10.1.2.2, 00:31:46, GigabitEthernet0/0/1

10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks

C 10.1.1.0/24 is directly connected, GigabitEthernet0/0/0

L 10.1.1.2/32 is directly connected, GigabitEthernet0/0/0

C 10.1.2.0/24 is directly connected, GigabitEthernet0/0/1

L 10.1.2.1/32 is directly connected, GigabitEthernet0/0/1

O IA 10.1.3.0/24 [110/2] via 10.1.2.2, 00:31:46, GigabitEthernet0/0/1


-------------------------------------

R3 ip route:

R3#sh ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, 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 1.1.1.1/32 [110/3] via 10.1.2.1, 00:32:27, GigabitEthernet0/1

2.0.0.0/32 is subnetted, 1 subnets

O 2.2.2.2/32 [110/2] via 10.1.2.1, 00:32:27, GigabitEthernet0/1

3.0.0.0/32 is subnetted, 1 subnets

C 3.3.3.3/32 is directly connected, Loopback0

4.0.0.0/32 is subnetted, 1 subnets

O 4.4.4.4/32 [110/2] via 10.1.3.2, 00:32:32, GigabitEthernet0/0

10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks

O IA 10.1.1.0/24 [110/2] via 10.1.2.1, 00:32:27, GigabitEthernet0/1

C 10.1.2.0/24 is directly connected, GigabitEthernet0/1

L 10.1.2.2/32 is directly connected, GigabitEthernet0/1

C 10.1.3.0/24 is directly connected, GigabitEthernet0/0

L 10.1.3.1/32 is directly connected, GigabitEthernet0/0

-----------------------------------------------------

R4 ip route:

R4#sh ip route

Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, 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 1.1.1.1/32 [110/4] via 10.1.3.1, 00:33:08, GigabitEthernet0/0

2.0.0.0/32 is subnetted, 1 subnets

O IA 2.2.2.2/32 [110/3] via 10.1.3.1, 00:33:08, GigabitEthernet0/0

3.0.0.0/32 is subnetted, 1 subnets

O IA 3.3.3.3/32 [110/2] via 10.1.3.1, 00:33:08, GigabitEthernet0/0

4.0.0.0/32 is subnetted, 1 subnets

C 4.4.4.4/32 is directly connected, Loopback0

10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks

O IA 10.1.1.0/24 [110/3] via 10.1.3.1, 00:33:08, GigabitEthernet0/0

O IA 10.1.2.0/24 [110/2] via 10.1.3.1, 00:33:08, GigabitEthernet0/0

C 10.1.3.0/24 is directly connected, GigabitEthernet0/0

L 10.1.3.2/32 is directly connected, GigabitEthernet0/0