Day 3 - OSPF Summarization - Summary Address

Pada lab kali ini, kita akan membahas bagaimana cara melakukan konfigurasi summarization pada routing OSPF menggunakan command 'summary-address'.

Lab 15 - OSPF Summarization - Summary Address

Topologi yang digunakan adalah sbb :


Konfigurasi R1 :

interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface Loopback1
 ip address 100.100.100.1 255.255.255.255
!
interface Loopback2
 ip address 100.100.100.2 255.255.255.255
!
interface Loopback3
 ip address 100.100.100.3 255.255.255.255
!
interface Loopback4
 ip address 100.100.100.4 255.255.255.255
!
interface Serial0/0
 ip address 12.12.12.1 255.255.255.0
!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 redistribute eigrp 10 subnets
 network 1.1.1.1 0.0.0.0 area 0
 network 12.12.12.1 0.0.0.0 area 0

 redistribute eigrp 10 subnets
!

router eigrp 10
 network 100.100.100.1 0.0.0.0
 network 100.100.100.2 0.0.0.0
 network 100.100.100.3 0.0.0.0
 network 100.100.100.4 0.0.0.0
 no auto-summary

Konfigurasi R2 :

interface Loopback0
 ip address 2.2.2.2 255.255.255.255
!
interface FastEthernet0/0
 ip address 23.23.23.2 255.255.255.0
!
interface Serial0/0
 ip address 12.12.12.2 255.255.255.0
!

router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

Konfigurasi R3 :

interface Loopback0
 ip address 3.3.3.3 255.255.255.255
!
interface FastEthernet0/0
 ip address 23.23.23.3 255.255.255.0
!

router ospf 1
 router-id 3.3.3.3
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0

Kita cek routing table di R3 :

R3#sh ip route

Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/75] via 23.23.23.2, 00:01:19, FastEthernet0/0
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/11] via 23.23.23.2, 00:01:19, FastEthernet0/0
     100.0.0.0/32 is subnetted, 4 subnets
O E2    100.100.100.4 [110/20] via 23.23.23.2, 00:01:19, FastEthernet0/0
O E2    100.100.100.1 [110/20] via 23.23.23.2, 00:01:19, FastEthernet0/0
O E2    100.100.100.2 [110/20] via 23.23.23.2, 00:01:19, FastEthernet0/0
O E2    100.100.100.3 [110/20] via 23.23.23.2, 00:01:19, FastEthernet0/0
     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
     12.0.0.0/24 is subnetted, 1 subnets
O       12.12.12.0 [110/74] via 23.23.23.2, 00:01:20, FastEthernet0/0

Terlihat bahwa semua routing IP Loopback R1 sudah diterima oleh R3.

Sekarang kita konfigurasikan external route summarization di R1.
R1(config)#router ospf 1
R1(config-router)#summary-address 100.100.100.0 255.255.255.248
 
Kita cek lagi di routing table R3 : 

R3#sh ip route

Gateway of last resort is not set

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/75] via 23.23.23.2, 00:04:24, FastEthernet0/0
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/11] via 23.23.23.2, 00:04:24, FastEthernet0/0
     100.0.0.0/29 is subnetted, 1 subnets
O E2    100.100.100.0 [110/20] via 23.23.23.2, 00:00:39, FastEthernet0/0
     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
     12.0.0.0/24 is subnetted, 1 subnets
O       12.12.12.0 [110/74] via 23.23.23.2, 00:04:24, FastEthernet0/0

Terlihat bahwa sekarang R3 hanya menerima routing 1 baris untuk IP Loopback R1 (100.100.100.0/29).

Kita cek juga di routing table R1 :

R1(config-router)#do sh ip route
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 [110/65] via 12.12.12.2, 00:04:55, Serial0/0
     100.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
C       100.100.100.4/32 is directly connected, Loopback4
O       100.100.100.0/29 is a summary, 00:01:10, Null0
C       100.100.100.1/32 is directly connected, Loopback1
C       100.100.100.2/32 is directly connected, Loopback2
C       100.100.100.3/32 is directly connected, Loopback3
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/75] via 12.12.12.2, 00:04:55, Serial0/0
     23.0.0.0/24 is subnetted, 1 subnets
O       23.23.23.0 [110/74] via 12.12.12.2, 00:05:04, Serial0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, Serial0/0

Untuk menghilangkan discard route (Null0) kita tambahkan command :

R1(config-router)#no discard-route external

R1(config-router)#do sh ip route

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 [110/65] via 12.12.12.2, 00:06:35, Serial0/0
     100.0.0.0/32 is subnetted, 4 subnets
C       100.100.100.4 is directly connected, Loopback4
C       100.100.100.1 is directly connected, Loopback1
C       100.100.100.2 is directly connected, Loopback2
C       100.100.100.3 is directly connected, Loopback3
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/75] via 12.12.12.2, 00:06:35, Serial0/0
     23.0.0.0/24 is subnetted, 1 subnets
O       23.23.23.0 [110/74] via 12.12.12.2, 00:06:35, Serial0/0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, Serial0/0

Terlihat bahwa discard route sudah tidak ada lagi di routing table R1.