Lab 57 - OSPF Gre Tunnel

Pada lab sebelumnya kita telah belajar mengkonfigurasi Virtual Link, selanjutnya kita juga bisa menggunakan Gre Tunnel sebagai alternatif lain. Berikut topologi yang akan kita gunakan pada lab ini

Gambar 1 Topologi jaringan multi area OSPF

Topologi diatas merupakan topologi yang kita gunakan pada lab sebelumnya. Sebelum melanjutkan lab ini, kita harus menghapus konfigurasi virtual link yang telah kita lakukan sebelumnya

R1(config)#router ospf 1
R1(config-router)#no area 1 virtual-link 2.2.2.2 

R2(config)#router ospf 1
R2(config-router)#no area 1 virtual-link 1.1.1.1

R2(config)#router ospf 1
R2(config-router)#no area 2 virtual-link 3.3.3.3

R3(config)#router ospf 1
R3(config-router)#no area 2 virtual-link 2.2.2.2

Pastikan bahwa R1 sudah tidak memiliki informasi tentang network-network yang berada di area 2 dan area 3

R1(config-router)#do sh ip ro
1.0.0.0/32 is subnetted, 1 subnets
C        1.1.1.1 is directly connected, Loopback0
      2.0.0.0/32 is subnetted, 1 subnets
O        2.2.2.2 [110/11] via 12.12.12.2, 00:03:57, 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

Selanjutnya kita konfigurasi Gre Tunnel untuk menghubungkan area 2 dengan area 0

R1(config)#int tun0
R1(config-if)#tunnel source 12.12.12.1
R1(config-if)#tunnel destination 12.12.12.2
R2(config-if)#ip add 102.102.102.1 255.255.255.0

R1(config-if)#router ospf 1
R1(config-router)#net 102.102.102.0 0.0.0.255 are 0

R2(config)#int tun0
R2(config-if)#tunnel source 12.12.12.2
R2(config-if)#tunnel destination 12.12.12.1
R2(config-if)#ip add 102.102.102.2 255.255.255.0

R2(config-if)#router ospf 1
R2(config-router)#net 102.102.102.0 0.0.0.255 are 0

Sekarang kita coba lihat tabel routing di R1

R1(config-router)#do sh ip ro

      1.0.0.0/32 is subnetted, 1 subnets
C        1.1.1.1 is directly connected, Loopback0
      2.0.0.0/32 is subnetted, 1 subnets
O        2.2.2.2 [110/11] via 12.12.12.2, 00:28:57, 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
      23.0.0.0/24 is subnetted, 1 subnets
O IA     23.23.23.0 [110/1010] via 102.102.102.2, 00:00:43, Tunnel0
      102.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        102.102.102.0/24 is directly connected, Tunnel0

Perhatikan bahwa saat ini R1 sudah memiliki informasi tentang network yang berada di area 2. Selanjutnya kita buat Gre Tunnel untuk menghubungkan area 3 dengan area 0

R2(config)#int tun1
R2(config-if)#tunnel source 23.23.23.2
R2(config-if)#tunnel destination 23.23.23.3
R2(config-if)#ip add 203.203.203.2 255.255.255.0

R2(config-if)#router ospf 1
R2(config-router)#net 203.203.203.0 0.0.0.255 are 0

R3(config)#int tun0
R3(config-if)#tunnel source 23.23.23.3
R3(config-if)#tunnel destination 23.23.23.2
R3(config-if)#ip add 203.203.203.3 255.255.255.0

R3(config-if)#router ospf 1
R3(config-router)#net 203.203.203.0 0.0.0.255 are 0

Sekarang kita coba lihat tabel routing di R1

R1(config-router)#do sh ip ro

      1.0.0.0/32 is subnetted, 1 subnets
C        1.1.1.1 is directly connected, Loopback0
      2.0.0.0/32 is subnetted, 1 subnets
O        2.2.2.2 [110/11] via 12.12.12.2, 00:31:46, Ethernet0/0
      3.0.0.0/32 is subnetted, 1 subnets
O IA     3.3.3.3 [110/2001] via 102.102.102.2, 00:00:23, Tunnel0
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0
      23.0.0.0/24 is subnetted, 1 subnets
O IA     23.23.23.0 [110/1010] via 102.102.102.2, 00:03:32, Tunnel0
      102.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        102.102.102.0/24 is directly connected, Tunnel0
O     203.203.203.0/24 [110/2000] via 102.102.102.2, 00:01:20, Tunnel0

Perhatikan bahwa saat ini R1 sudah memiliki informasi tentang network yang berada di area 2 dan area 3.