Lab 44. OSPF Virtual Link

Pada lab kali ini, topoplogi areanya adalah Area 0 - Area 1 - Area 2 - Area 3. Dimana Area 2 dan Area 3 tidak terhubung langsung dengan area 0, padahal syarat utamanya adalah semua area selain area 0 harus tersambung dengan area 0. Untuk itu, salah satu solusimya adalah Virtual Link. Oke, langsung saja kita ke TKP ..

1. Topologi Lab

2. Metode Lab

• Gunakan pengalamatan ip standard IDN
• Konfigurasikan OSPF dengan area seperti pada gambar
• Konfigurasikan virtual link agar tabel routing pada semua router menjadi lengkap

3. Verifikasi

• Cek ip route di semua router
• Setelah dikonfigurasi virtual link, pastikan tabel route sudah lengkap semua

4. Konfigurasi

IDN-R1(config)#int f0/0
IDN-R1(config-if)#no sh
IDN-R1(config-if)#ip add 12.12.12.1 255.255.255.0
IDN-R1(config-if)#int l0
IDN-R1(config-if)#ip add 1.1.1.1 255.255.255.255
IDN-R1(config-if)#router ospf 1
IDN-R1(config-router)#router
IDN-R1(config-router)#router-id 1.1.1.1
IDN-R1(config-router)#network 1.1.1.1 0.0.0.0 area 0
IDN-R1(config-router)#network 12.12.12.1 0.0.0.0 area 1

IDN-R2(config)#int f0/0
IDN-R2(config-if)#no sh
IDN-R2(config-if)#ip add 12.12.12.2 255.255.255.0
IDN-R2(config-if)#int f0/1
IDN-R2(config-if)#no sh
IDN-R2(config-if)#ip add 23.23.23.2 255.255.255.0
IDN-R2(config-if)#int l0
IDN-R2(config-if)#ip add 2.2.2.2 255.255.255.255
IDN-R2(config-if)#router ospf 1
IDN-R2(config-router)#router-id 2.2.2.2
IDN-R2(config-router)#network 2.2.2.2 0.0.0.0 area 1
IDN-R2(config-router)#network 12.12.12.2 0.0.0.0 area 1
IDN-R2(config-router)#network 23.23.23.2 0.0.0.0 area 2

IDN-R3(config)#int f0/0
IDN-R3(config-if)#no sh
IDN-R3(config-if)#ip add 23.23.23.3 255.255.255.0
IDN-R3(config-if)#int l0
IDN-R3(config-if)#ip add 3.3.3.3 255.255.255.255
IDN-R3(config-if)#router ospf 1
IDN-R3(config-router)#router-id 3.3.3.3
IDN-R3(config-router)#network 23.23.23.3 0.0.0.0 area 2
IDN-R3(config-router)#network 3.3.3.3 0.0.0.0 area 3

Coba kita cek routing tabelnya

IDN-R1(config-router)#do sh ip route | b Gateway
Gateway of last resort is not set
     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, 00:02:15, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, FastEthernet0/0

IDN-R2(config-router)#do sh ip route | b Gateway
Gateway of last resort is not set
     1.0.0.0/32 is subnetted, 1 subnets
O IA    1.1.1.1 [110/11] via 12.12.12.1, 00:02:24, FastEthernet0/0
     2.0.0.0/32 is subnetted, 1 subnets
C       2.2.2.2 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.23.23.0 is directly connected, FastEthernet0/1
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, FastEthernet0/0

IDN-R3(config-router)#do sh ip route | b Gateway
Gateway of last resort is not set
     3.0.0.0/32 is subnetted, 1 subnets
C       3.3.3.3 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.23.23.0 is directly connected, FastEthernet0/0

Bisa kita lihat, di ketiga router tersebut tabel routingnya tidak lengkap. Selanjutnya konfigurasikan virtual link pada IDN-R2 dan IDN-R3.Virtual link ini dikonfigurasikan dua sisi, pertama antara IDN-R1 dan IDN-R2 dulu. Berikutnya antara IDN-R3 dan IDN-R2.
Untuk IDN-R2 dimana terdapat area 2 di dalamnya yang tidak terhubung langsung dengan area 0. maka virtual link dibuat melalui area 1 sebagai jembatannya.

IDN-R2(config)#router ospf 1
IDN-R2(config-router)#area 1 virtual-link 1.1.1.1

IDN-R1(config)#router ospf 1
IDN-R1(config-router)#area 1 virtual-link 2.2.2.2

Sekarang kita cek lagi ip route nya

IDN-R1(config-router)#do sh ip route | b Gateway
Gateway of last resort is not set
     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, 03:03:18, FastEthernet0/0
     23.0.0.0/24 is subnetted, 1 subnets
O IA    23.23.23.0 [110/20] via 12.12.12.2, 00:01:18, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, FastEthernet0/0

Bisa kita lihat, network di area 2 sekarang sudah muncul, namun tampaknya yang berada di area 3 belum muncul.
Berikutnya kita konfigurasikan virtual link di IDN-R3 yang terdapat area 3 di dalamnya. Untuk terhubung ke area 0, maka area 2 digunakan sebagai jembatannya.

IDN-R3(config-router)#router ospf 1
IDN-R3(config-router)#area 2 virtual-link 2.2.2.2

IDN-R2(config)#router ospf 1
IDN-R2(config-router)#area 2 virtual-link 3.3.3.3

Sekarang cek lagi di IDN-R1. Pastikan semua ip sudah muncul di routing tabelnya. Bisa juga lakukan ping.

IDN-R1(config-router)#do sh ip route | b Gateway
Gateway of last resort is not set
     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, 03:07:58, FastEthernet0/0
     3.0.0.0/32 is subnetted, 1 subnets
O IA    3.3.3.3 [110/21] via 12.12.12.2, 00:00:47, FastEthernet0/0
     23.0.0.0/24 is subnetted, 1 subnets
O IA    23.23.23.0 [110/20] via 12.12.12.2, 00:05:57, FastEthernet0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, FastEthernet0/0

IDN-R1(config)#do ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 36/59/76 ms