Lab 7. MPLS & L3VPN Menggunakan OSPF Routing dan Backup Link
Topologi dan konfigurasi masih sama dengan lab yang sebelumnya.
Ada penambahan link backup OSPF antar R1 dan R5, serta Shamlink
Ketika pada sebuah router terdapat dua type OSPF, yang satu OSPF yang
menghubungkan R2-PE R3-P dan R4-PE, dan yang satu OSPF yang berjalan melewati
VPN menggunakan VRF(Virtual Routing Forwarding) yang menghubungkan CAR2 dan
CAR4 serta CBR6, kemudian ada link backup antara CAR2 langsung terhubng ke CAR4
agar link backup tersebut dapat standby, ktika link mpls mati, maka link
backup ini yang menghandle, dibutuhkan sebuah teknik yaitu Sham Link
Shamlink merupakan OSPF Intra Area yang di konfigurasikan diantara 2 PE,
Shamlink sudah termasuk dan perhitungan SPF, seperi link yang lain didalam
OSPF.
Ketika LSA bersebaran diantara link ini, semua tipe rute ospf dipertahankan
dan tidak harus dikonversikan ke Intra Area atau external.
Artinya ia akan mengenal rute ospf yang asli sesuai typenya masing masing.
Konfigurasikan IP Address Link Backup pada router R2-PE
interface Loopback24
ip vrf forwarding car2
ip address 24.24.24.2 255.255.255.255
!
Kemudian konfigurasi Shamlink di OSPF
router ospf 100 vrf car2
area 0 sham-link 24.24.24.2 24.24.24.4
Kemudian advertise ke MP-BGP
router bgp 234
address-family ipv4 vrf car2
network 24.24.24.2 mask 255.255.255.255
!
Konfigurasikan IP Address Link Backup pada router R4-PE
interface Loopback24
ip vrf forwarding car4
ip address 24.24.24.4 255.255.255.255
!
Kemudian konfigurasi Shamlink
router ospf 100 vrf car4
area 0 sham-link 24.24.24.4 24.24.24.2
!
Kemudian Advertise ke MP-BGP
router bgp 234
address-family ipv4 vrf car4
network 24.24.24.4 mask 255.255.255.255
!
selanjutnya konfigurasi IP Address dan OSPF link CAR2 dan CAR4
car2(config)#int e0/1
car2(config-if)#ip add 15.15.15.1 255.255.255.0
car2(config-if)#no shut
car2(config)#router ospf 100
car2(config-router)#net 15.15.15.1 0.0.0.0 area 0
car2(config-router)#exit
car4(config)#int e0/1
car4(config-if)#ip add 15.15.15.5 255.255.255.0
car4(config-if)#no shut
car4(config)#router ospf 100
car4(config-router)#net 15.15.15.5 0.0.0.0 area 0
car4(config-router)#exit
kita verifikasi OSPFnya yah di CAR2
car2(config)#do sh ip route | i 0
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/11] via 15.15.15.5, 00:02:32, Ethernet0/1
6.0.0.0/32 is subnetted, 1 subnets
O E2 6.6.6.6 [110/1] via 12.12.12.2, 00:09:01, 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
L 12.12.12.1/32 is directly connected, Ethernet0/0
15.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 15.15.15.0/24 is directly connected, Ethernet0/1
L 15.15.15.1/32 is directly connected, Ethernet0/1
24.0.0.0/32 is subnetted, 2 subnets
O E2 24.24.24.2 [110/1] via 12.12.12.2, 00:09:01, Ethernet0/0
O E2 24.24.24.4 [110/1] via 12.12.12.2, 00:09:01, Ethernet0/0
45.0.0.0/24 is subnetted, 1 subnets
O 45.45.45.0 [110/20] via 15.15.15.5, 00:02:32, Ethernet0/1
46.0.0.0/24 is subnetted, 1 subnets
O E2 46.46.46.0 [110/1] via 12.12.12.2, 00:09:01, Ethernet0/0
Tes trace route CAR2 ke CAR4
car2(config)#do trace 5.5.5.5
Type escape sequence to abort.
Tracing the route to 5.5.5.5
VRF info: (vrf in name/id, vrf out name/id)
1 15.15.15.5 8 msec 8 msec 7 msec
Loh kok OSPF memilih jalur CAR2 yang direct langsung ke CAR4 sih,
kan seharusnya link utama adalh melewati network MPLS, kok jadi link
backup yang menjadi link utama yah ?? ada apakah gerangan ?
ternyata setelah kita baca tabel routingnya, permasalahnya ada pada letak
nilai cost,
Link Backup
O 5.5.5.5 [110/11] via 15.15.15.5, 00:02:32, Ethernet0/1
bandingka dengan ini link mpls :
45.0.0.0/24 is subnetted, 1 subnets
O 45.45.45.0 [110/20] via 15.15.15.5, 00:02:32, Ethernet0/1
lihat disana link backup costnya lebih kecil dari link mpls, oleh karena itu
kita akalin dengan besarin aja costnya di interface link CAR2 yang direct ke
CAR4.
car2(config)#int e0/1
car2(config-if)#ip ospf cost 25
car2(config-if)#no shut
car2(config-if)#exit
car4(config)#int e0/1
car4(config-if)#ip ospf cost 25
car4(config-if)#no shut
car4(config-if)#exit
Oke kita verifikasi
car2(config)#do sh ip route
Codes: L - local, 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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override
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
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/22] via 12.12.12.2, 00:02:53, Ethernet0/0
6.0.0.0/32 is subnetted, 1 subnets
O E2 6.6.6.6 [110/1] via 12.12.12.2, 00:16:02, 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
L 12.12.12.1/32 is directly connected, Ethernet0/0
15.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 15.15.15.0/24 is directly connected, Ethernet0/1
L 15.15.15.1/32 is directly connected, Ethernet0/1
24.0.0.0/32 is subnetted, 2 subnets
O E2 24.24.24.2 [110/1] via 12.12.12.2, 00:16:02, Ethernet0/0
O E2 24.24.24.4 [110/1] via 12.12.12.2, 00:16:02, Ethernet0/0
45.0.0.0/24 is subnetted, 1 subnets
O 45.45.45.0 [110/21] via 12.12.12.2, 00:02:53, Ethernet0/0
46.0.0.0/24 is subnetted, 1 subnets
O E2 46.46.46.0 [110/1] via 12.12.12.2, 00:16:02, Ethernet0/0
car2(config)#
Dari tabel routing terlihat bahwa link menuju backup tidak dijadikan link utama
link utama skrang adalah MPLS
selanjutnya tes ping dan trace route ke CAR4
car2(config)#do ping 5.5.5.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 2/5/8 ms
car2(config)#
car2(config)#do trace 5.5.5.5
Type escape sequence to abort.
Tracing the route to 5.5.5.5
VRF info: (vrf in name/id, vrf out name/id)
1 12.12.12.2 9 msec 6 msec 5 msec
2 23.23.23.3 [MPLS: Labels 18/16 Exp 0] 3 msec 6 msec 3 msec
3 45.45.45.4 [MPLS: Label 16 Exp 0] 2 msec 5 msec 1 msec
4 45.45.45.5 0 msec 1 msec 0 msec
car2(config)#
Mantab mas bro, skarang CAR2 memilih jalur link utama yaitu MPLS sebagai jalur
Utamanya, Sampai sini selesei.
Salam Ngoprek