Objective
Mempelajari pengaruh Stub area pada OSPF

Metode Lab
Masih menggunakan topologi dan konfigurasi sebelumnya
Konfigurasikn STUB pada semua router di OSPF Area 1 yakni RM-R2 dan RM-R3

Verifikasi Lab
Periksa routing tabel pada router RM-R3

• Stub artinya ujung, merupakan router atau area yang paling ujung atau sisi paling akhir dan tidak memiliki cabang lain serta tidak memiliki jalan lain untuk menuju jaringan dengan segmen lain

• Semua external route LSA tipe 4 dan 5 (network dari routing lain yang diredistribute ke dalam OSPF) tidak dimasukan dalam routing tabel

• Sebagai gantinya digunakanlah default route untuk menuju ke network2 tersebut
• Hal ini akan mengurangi kinerja CPU daMemori Router, mengurangi jumlah routing tabel

• Dikonfigurasikan di semua router yang ada dalam 1 stub area

RM-R2(config)#router os 2
RM-R2(config-router)#area 1 stub
RM-R2(config-router)#
*Mar  1 00:36:09.111: %OSPF-5-ADJCHG: Process 2, Nbr 3.3.3.3 on Serial0/0 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
RM-R3(config)#router os 3
RM-R3(config-router)#area 1 stub
RM-R3(config-router)#
*Mar  1 00:36:07.131: %OSPF-5-ADJCHG: Process 3, Nbr 2.2.2.2 on Serial0/0 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
RM-R3(config-router)#
*Mar  1 00:36:09.263: %OSPF-5-ADJCHG: Process 3, Nbr 2.2.2.2 on Serial0/0 from LOADING to FULL, Loading Done

Hasilnya berikut routing tabel di router RM-R3

RM-R3(config-router)#do sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is 23.23.23.2 to network 0.0.0.0

     1.0.0.0/32 is subnetted, 1 subnets
O IA    1.1.1.1 [110/75] via 23.23.23.2, 00:00:36, Serial0/0
     2.0.0.0/32 is subnetted, 1 subnets
O       2.2.2.2 [110/65] via 23.23.23.2, 00:00:36, Serial0/0
     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, Serial0/0
     10.0.0.0/32 is subnetted, 3 subnets
O IA    10.10.10.2 [110/75] via 23.23.23.2, 00:00:36, Serial0/0
O IA    10.10.10.3 [110/75] via 23.23.23.2, 00:00:40, Serial0/0
O IA    10.10.10.1 [110/75] via 23.23.23.2, 00:00:40, Serial0/0
     12.0.0.0/24 is subnetted, 1 subnets
O IA    12.12.12.0 [110/74] via 23.23.23.2, 00:00:44, Serial0/0
O*IA 0.0.0.0/0 [110/65] via 23.23.23.2, 00:00:44, Serial0/0
RM-R3(config-router)#
RM-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         263         0x80000006 0x00EEEF 3
3.3.3.3         3.3.3.3         259         0x80000004 0x008D4B 3

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         2.2.2.2         296         0x80000001 0x0075C0
1.1.1.1         2.2.2.2         296         0x80000002 0x00A97D
10.10.10.1      2.2.2.2         296         0x80000002 0x0064A7
10.10.10.2      2.2.2.2         296         0x80000002 0x005AB0
10.10.10.3      2.2.2.2         296         0x80000002 0x0050B9
12.12.12.0      2.2.2.2         296         0x80000002 0x001CEB
RM-R3(config-router)#

Dalam database OSPF, LSA tipe 4 dan 5 sudah tidak lagi terdapat didalamnya