Lab 79 - IBGP Full Mesh Cisco

Pada lab ini kita akan mempelajari tentang masalah full mesh pada IBGP. Berikut topologi yang akan kita gunakan pada lab ini

Gambar 1 Topologi jaringan IBGP

Langsung aja kita konfig IBGP pada seluruh router

R1(config)#int e0/0
R1(config-if)#no sh
R1(config-if)#ip add 12.12.12.1 255.255.255.0

R1(config-if)#int lo0
R1(config-if)#ip add 1.1.1.1 255.255.255.255

R1(config-if)#router bgp 123
R1(config-router)#neighbor 12.12.12.2 remote-as 123  
R1(config-router)#network 1.1.1.1 mask 255.255.255.255      

R2(config)#int e0/0
R2(config-if)#no sh
R2(config-if)#ip add 12.12.12.2 255.255.255.0

R2(config-if)#int e0/1
R2(config-if)#no sh
R2(config-if)#ip add 23.23.23.2 255.255.255.0

R2(config-if)#int lo0
R2(config-if)#ip add 2.2.2.2 255.255.255.255

R2(config-if)#router bgp 123
R2(config-router)#neighbor 12.12.12.1 remote-as 123
R2(config-router)#neighbor 23.23.23.3 remote-as 123
R2(config-router)#network 2.2.2.2 mask 255.255.255.255

R3(config)#int e0/0
R3(config-if)#no sh
R3(config-if)#ip add 23.23.23.3 255.255.255.0

R3(config-if)#int lo0
R3(config-if)#ip add 3.3.3.3 255.255.255.255

R3(config-if)#router bgp 123
R3(config-router)#neighbor 23.23.23.2 remote-as 123
R3(config-router)#network 3.3.3.3 mask 255.255.255.255

Oke udah selesai, sekarang kita coba lihat tabel routing diseluruh router

R1(config-router)#do sh ip ro

      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
B        2.2.2.2 [200/0] via 12.12.12.2, 00:00:10
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0

R2(config-router)#do sh ip ro

      1.0.0.0/32 is subnetted, 1 subnets
B        1.1.1.1 [200/0] via 12.12.12.1, 00:00:20
      2.0.0.0/32 is subnetted, 1 subnets
C        2.2.2.2 is directly connected, Loopback0
      3.0.0.0/32 is subnetted, 1 subnets
B        3.3.3.3 [200/0] via 23.23.23.3, 00:00:09
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0
      23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        23.23.23.0/24 is directly connected, Ethernet0/1

R3(config-router)#do sh ip ro

      2.0.0.0/32 is subnetted, 1 subnets
B        2.2.2.2 [200/0] via 23.23.23.2, 00:00:17
      3.0.0.0/32 is subnetted, 1 subnets
C        3.3.3.3 is directly connected, Loopback0
      23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        23.23.23.0/24 is directly connected, Ethernet0/0

Coba kita lihat, R1 cuma punya informasi tentang 2.2.2.2, R3 juga cuma punya 2.2.2.2. Lho kog gitu? iya emang gitu...

Kog bisa gitu? karena syarat IBGP itu harus full mesh. artinya R1 harus peering dengan R2 dan R3. R2 harus peering dengan R1 dan R3, dan R3 juga harus peering dengan R1 dan R2.

Nah sekarang yang masih kurang adalah R1 belum peering sama R3. coba kita konfig deh

R1(config)#router bgp 123
R1(config-router)#neighbor 23.23.23.3 remote-as 123

R3(config)#router bgp 123
R3(config-router)#neighbor 12.12.12.1 remote-as 123

Coba kita cek lagi ya

R1(config-router)#do sh ip ro

      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
B        2.2.2.2 [200/0] via 12.12.12.2, 00:09:21
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0

Lho kog tetep? coba kita lihat tabel adjacency nya deh

R1(config-router)#do sh ip bgp summary
BGP router identifier 1.1.1.1, local AS number 123
BGP table version is 3, main routing table version 3
2 network entries using 240 bytes of memory
2 path entries using 104 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 592 total bytes of memory
BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
12.12.12.2      4    123      48      50        3    0    0 00:41:42        1
23.23.23.3      4    123       0       0        0    0    0 never    Idle

Lha kog idle? Yo iyo lah.. kan R1 gurung biso ping 23.23.23.3? kwkwkwkwk gk paham ya? kenapa masih idle? karena R1 belum bisa ping ke 23.23.23.3, begitu juga R3 juga belum bisa ping 12.12.12.1. Kita setting routingnya dulu, boleh pake static, boleh juga dynamic

R1(config-router)#ip route 23.23.23.0 255.255.255.0 12.12.12.2

R3(config-router)#ip route 12.12.12.0 255.255.255.0 23.23.23.2

Coba cek lagi deh

R1(config)#do sh ip ro

      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
B        2.2.2.2 [200/0] via 12.12.12.2, 00:12:32
      3.0.0.0/32 is subnetted, 1 subnets
B        3.3.3.3 [200/0] via 23.23.23.3, 00:00:35
      12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        12.12.12.0/24 is directly connected, Ethernet0/0
      23.0.0.0/24 is subnetted, 1 subnets
S        23.23.23.0 [1/0] via 12.12.12.2

Juozzz.. R1 udah punya informasi tentang 2.2.2.2 dan 3.3.3.3. Coba ping deh

R1(config)#do ping 2.2.2.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
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 = 1/1/4 ms

sip sip R1 udah bisa ping ke 2.2.2.2 dan 3.3.3.3