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