Day 3 - OSPF Totally Stub Area

Pada lab sebelumnya kita sudah membahas bagaimana cara konfigurasi stub area pada OSPF, kita lanjut ke pembahasan totally stub area OSPF.
Pada totally stub bukan hanya external route yang tidak dimasukkan ke routing table, tapi juga internal route OSPF juga di reject.
Konfigurasi hanya dilakukan di ABR nya saja, tidak pada semua router dalam satu stub area.
Router R2 adalah sebagai ABR yang menghubungkan Area 0 dan Stub Area 1.

Lab 5 - OSPF Totally Stub Area

Topologi yang digunakan adalah sbb :


Skenarionya adalah untuk Area 1 akan kita jadikan stub area.
 
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 Loopback5
 ip address 100.100.100.5 255.255.255.255
!
interface Loopback6
 ip address 100.100.100.6 255.255.255.255
!
interface Loopback7
 ip address 100.100.100.7 255.255.255.255
!
interface Serial0/0
 ip address 12.12.12.1 255.255.255.0
!
router eigrp 1
 network 100.100.100.4 0.0.0.0
 network 100.100.100.5 0.0.0.0
 network 100.100.100.6 0.0.0.0
 network 100.100.100.7 0.0.0.0
!

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 redistribute eigrp 1 subnets
 network 1.1.1.1 0.0.0.0 area 0
 network 12.12.12.1 0.0.0.0 area 0
 network 100.100.100.1 0.0.0.0 area 100
 network 100.100.100.2 0.0.0.0 area 100
 network 100.100.100.3 0.0.0.0 area 100

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 2
 router-id 2.2.2.2
 log-adjacency-changes

 area 1 stub
 network 2.2.2.2 0.0.0.0 area 1
 network 12.12.12.2 0.0.0.0 area 0
 network 23.23.23.2 0.0.0.0 area 1

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 3
 router-id 3.3.3.3
 log-adjacency-changes

 area 1 stub
 network 3.3.3.3 0.0.0.0 area 1
 network 23.23.23.3 0.0.0.0 area 1

Sekarang kita coba rubah untuk area 1 menjadi totally stub area.
Perubahan dilakukan hanya pada router R2 :

R2(config-router)#no area 1 stub
R2(config-router)#area 1 stub no-summary
R2(config-router)#
*Mar  1 00:35:51.899: %OSPF-5-ADJCHG: Process 2, Nbr 3.3.3.3 on FastEthernet0/0 from DOWN to DOWN, Neighbor Down: Adjacency forced to reset

Setelah kita tunggu sebentar, kita cek routing table di R3 :
R3(config-router)#do sh ip route
Gateway of last resort is 23.23.23.2 to network 0.0.0.0

     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/11] via 23.23.23.2, 00:10:38, 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
O*IA 0.0.0.0/0 [110/11] via 23.23.23.2, 00:10:38, FastEthernet0/0


Terlihat bahwa pada R3 sudah tidak menerima lagi routing dari internal OSPF.
Dan default route tetap ada pada routing table R3.


Kita cek juga di ip ospf databse :
R3(config-router)#do sh ip ospf database

            OSPF Router with ID (3.3.3.3) (Process ID 3)

                Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         152         0x80000008 0x00DE8C 2
3.3.3.3         3.3.3.3         283         0x80000006 0x00F36D 2

                Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
23.23.23.3      3.3.3.3         283         0x80000004 0x00CA06

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         2.2.2.2         156         0x80000003 0x0071C2

Terlihat bahwa dalam OSPF database semua LSA tipe 3 kecuali default route sudah dihapus.