CCNP - eBGP Peering

 Lab 3 eBGP Peering

Pada lab ini kita akan mengkonfigurasi eBGP dengan 3, yaitu antara router 2 dan 3 eBGP-nya. Dan disini juga saya akan mengunakan IP physical, Ingat!!! bukan IP looback ya... 

R1(config)#int g2/0
R1(config-if)#no sh
R1(config-if)#ip ad 12.12.12.1 255.255.255.252
R1(config-if)#int lo0
R1(config-if)#ip ad 1.1.1.1 255.255.255.255

R2(config)#int ra g2/0,g3/0
R2(config-if-range)#no sh
R2(config-if-range)#int g2/0
R2(config-if)#ip ad 12.12.12.2 255.255.255.252
R2(config-if)#int g3/0
R2(config-if)#ip ad 23.23.23.1 255.255.255.252
R2(config-if)#int lo0
R2(config-if)#ip ad 2.2.2.2 2552.552.55.255

R3(config)#int g2/0
R3(config-if)#no sh
R3(config-if)#ip ad 23.23.23.2 255.255.255.252
R3(config-if)#int lo0
R3(config-if)#ip ad 3.3.3.3 255.255.255.255

Kita buat router BGP dam peering nya dulu

R1(config)#router bgp 10
R2(config)#router bgp 10
R3(config)#router bgp 20

Nah ketika router 3 itu beda AS number- nya dan router 1 dan 2 ingen terhubung maka inilah yang disebut eBGP kalau AS nya masih sama maka iBGP. Oke lanjut kita peering

R1(config-router)#neighbor 12.12.12.2 remote-as 10
R2(config-router)#neighbor 12.12.12.1 remote-as 10
R2(config-router)#neighbor 23.23.23.2 remote-as 20
R3(config-router)#neighbor 23.23.23.1 remote-as 10

Setelah itu kita masukan IP looback nya

R1(config-router)#net 1.1.1.1 mask 255.255.255.255
R2(config-router)#net 2.2.2.2 mask 255.255.255.255
R3(config-router)#net 3.3.3.3 mask 255.255.255.255

Kalau sampai sini kita mau test ping pasti gagal, karenakan IP Next Hopnya tidak reachable dari R1. Ketika paket ping dikirim dan sampai ke R1, R1 tidak mengetahui cara untuk mengembalikan paket icmp tersebut ke R3.

R1(config)#do sh ip route bgp
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
       + - replicated route, % - next hop override

Gateway of last resort is not set

      2.0.0.0/32 is subnetted, 1 subnets
B        2.2.2.2 [200/0] via 12.12.12.2, 00:03:43
R1(config)#

Di router 1 tidak ada network maupun loopbacknya router 3

Ada beberapa cara untuk mengatasi masalah ini, salah satunya adalah mengadvertise network 23.23.23.0 ke BGP pada R2.

R2(config-router)#network 23.23.23.0 mask 255.255.255.252

Kita cek di router 1

R1(config)#do sh ip route bgp
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
       + - replicated route, % - next hop override
Gateway of last resort is not set
      2.0.0.0/32 is subnetted, 1 subnets
B        2.2.2.2 [200/0] via 12.12.12.2, 00:08:45
      3.0.0.0/32 is subnetted, 1 subnets
B        3.3.3.3 [200/0] via 23.23.23.2, 00:00:37
      23.0.0.0/30 is subnetted, 1 subnets
B        23.23.23.0 [200/0] via 12.12.12.2, 00:00:42
R1(config)#

Sudah muncul, sebenarnya disini kita sudah bisa ping tapi harus dengan source

R1(config-router)#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 0 percent (0/5)
R1(config-router)#

R1(config)#do ping 3.3.3.3 source 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
Packet sent with a source address of 1.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/42/44 ms
R1(config)#


Untuk mengatasi ini kita advertise lagi network 12.12.12.0 di router 1 ke BGP nya 

R1(config-router)#network 12.12.12.0 mask 255.255.255.0
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 = 40/44/48 ms
R1(config)#

Selesai..... :)
























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