OSPF Lab 10

Tasks:

1. Configure OSPF according to the network diagram. In addition, R1 should be able to reach R3 interface and vice versa.

2. All fastethernet interfaces should be seen with a cost of 10. Do not use ip ospf or bandwidth commands.

3. Configure R1 to advertise a default route into the OSPF domain, as long as the subnet 111.111.23.0/24 exists in his routing table. This route should be seen with a cost of 20 on R2, and with a cost of 30 on R3. You are allowed to add a static route.

4. Configure R2 to suppress unnecessary flood of LSAs to R3.

Lab Diagram:

NB: Click here to download the .net file and the initial configuration files.

Solutions:

Task 1:

R1:
router ospf 1
network 111.111.2.1 0.0.0.0 area 0
network 111.111.12.1 0.0.0.0 area 12
area 12 virtual-link 111.111.23.2

R2:
router ospf 1
network 111.111.23.2 0.0.0.0 area 23
network 111.111.12.2 0.0.0.0 area 12
area 12 virtual-link 111.111.12.1

R3:
router ospf 1
network 111.111.23.3 0.0.0.0 area 23
network 111.111.3.3 0.0.0.0 area 23

Task 2:

R1, R2 & R3:
router ospf 1
auto-cost reference-bandwidth 1000

Verification:

R1#show ip ospf interface fastEthernet 0/0
… omitted output
Process ID 1, Router ID 111.111.12.1, Network Type BROADCAST, Cost: 10
… omitted output

R2#show ip ospf interface fastEthernet 0/0
… omitted output
Process ID 1, Router ID 111.111.23.2, Network Type BROADCAST, Cost: 10
… omitted output

R3#show ip ospf interface fastEthernet 0/0
… omitted output
Process ID 1, Router ID 111.111.23.3, Network Type BROADCAST, Cost: 10
… omitted output

Task 3:

R1:
ip route 0.0.0.0 0.0.0.0 null 0

ip prefix-list R2_R3_LINK seq 5 permit 111.111.23.0/24

route-map DEFAULT_ROUTE permit 10
match ip address prefix-list R2_R3_LINK
set metric 10
set metric-type type-1

router ospf 1
default-information originate route-map DEFAULT_ROUTE

Verification:

R2#sh ip route ospf
111.0.0.0/24 is subnetted, 4 subnets
O 111.111.2.0 [110/20] via 111.111.12.1, 00:05:33, FastEthernet0/0
O 111.111.3.0 [110/20] via 111.111.23.3, 00:10:15, FastEthernet0/1
O*E1 0.0.0.0/0 [110/20] via 111.111.12.1, 00:01:48, FastEthernet0/0

R3#sh ip route ospf
111.0.0.0/24 is subnetted, 4 subnets
O IA 111.111.2.0 [110/30] via 111.111.23.2, 00:10:04, FastEthernet0/0
O IA 111.111.12.0 [110/20] via 111.111.23.2, 00:10:04, FastEthernet0/0
O*E1 0.0.0.0/0 [110/30] via 111.111.23.2, 00:01:38, FastEthernet0/0

Task 4:

R2:
interface FastEthernet0/1
ip ospf flood-reduction

Verification:

R2#show ip ospf interface f0/1
… omitted output
Reduce LSA flooding.
… omitted output