Lab 58 - OSPF Redistribution Default Route

Pada lab ini kita akan belajar melakukan redistribute default route ke OSPF. Berikut topologi yang akan kita gunakan pada lab ini

Gambar 1 Topologi jaringan OSPF

Pertama kita konfigurasi OSPF pada ketiga router tersebut, dengan catatan kita tidak akan melakukan advertise IP Address Loopback R1, karena kita ingin melakukan redistribute default route.

R1(config)#int e0/0
R1(config-if)#no sh
R1(config-if)#ip add 12.12.12.1 255.255.255.0

R1(config-if)#int lo0
R1(config-if)#ip add 11.11.11.1 255.255.255.255

R1(config-if)#int lo1
R1(config-if)#ip add 11.11.11.2 255.255.255.255

R1(config-if)#int lo2
R1(config-if)#ip add 11.11.11.3 255.255.255.255

R1(config-if)#int lo3
R1(config-if)#ip add 11.11.11.4 255.255.255.255

R1(config-if)#int lo4     
R1(config-if)#ip add 11.11.11.5 255.255.255.255

R1(config-if)#int lo5
R1(config-if)#ip add 11.11.11.6 255.255.255.255

R1(config-if)#router ospf 1
R1(config-router)#net 12.12.12.0 0.0.0.255 are 0

R2(config)#int e0/0
R2(config-if)#no sh
R2(config-if)#ip add 12.12.12.2 255.255.255.0

R2(config-if)#int e0/1
R2(config-if)#no sh
R2(config-if)#ip add 23.23.23.2 255.255.255.0

R2(config-if)#router ospf 1
R2(config-router)#net 12.12.12.0 0.0.0.255 are 0
R2(config-router)#net 23.23.23.0 0.0.0.255 are 0

R3(config)#int e0/0
R3(config-if)#no sh
R3(config-if)#ip add 23.23.23.3 255.255.255.0

R3(config-if)#router ospf 1
R3(config-router)#net 23.23.23.0 0.0.0.255 are 0

Sekarang kita coba lihat tabel routing di R2 dan R3

R2(config-router)#do sh ip ro

      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0
      23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        23.23.23.0/24 is directly connected, Ethernet0/1

R3(config-router)#do sh ip ro

      12.0.0.0/24 is subnetted, 1 subnets
O        12.12.12.0 [110/20] via 23.23.23.2, 00:04:03, Ethernet0/0
      23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        23.23.23.0/24 is directly connected, Ethernet0/0

Perhatikan bahwa R2 dan R3 sama sekali tidak memiliki informasi tentang IP Loopback R1. Untuk itu kita akan melakukan redistribution default route di R1

R1(config)#router ospf 1
R1(config-router)#default-information originate always

Sekarang kita coba lihat lagi tabel routing di R2 dan R3

R2(config-router)#do sh ip ro

O*E2  0.0.0.0/0 [110/1] via 12.12.12.1, 00:00:03, Ethernet0/0
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0
      23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        23.23.23.0/24 is directly connected, Ethernet0/1

R3(config-router)#do sh ip ro

O*E2  0.0.0.0/0 [110/1] via 23.23.23.2, 00:00:39, Ethernet0/0
      12.0.0.0/24 is subnetted, 1 subnets
O        12.12.12.0 [110/20] via 23.23.23.2, 00:01:16, Ethernet0/0
      23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        23.23.23.0/24 is directly connected, Ethernet0/0

Perhatikan bahwa R2 dan R3 tetap saja tidak memiliki informasi tentang IP Loopback R1, namun kedua router ini telah memiliki default route. Coba kita lakukan ping dari R3 ke IP Loopback R1

R3(config-router)#do ping 11.11.11.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 11.11.11.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
R3(config-router)#do ping 11.11.11.6

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 11.11.11.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

Perhatikan bahwa R3 berhasil ping ke IP Loopback R1