iBGP PEERING - LOOPBACK

TUJUAN :

• Mempelajari bagaimana mengkonfigurasikan Peers BGP Internal menggunakan IP interface loopbacknya.

METODE :

• Gunakan topologi dasar BGP sebelumnya
• Hapus konfigurasi konfigurasi BGP sebelumnya
• Konfigurasikan iBGP Peers menggunakan ip loopbacknya
• Buat IP loopback baru untuk diadvertise ke BGP

 VERIVIKASI :

• Pastikan BGP adjacency terbentuk dengan mengetik "show ip bgp summary"
• Pastikan ada route yang di advertise ke BGP, ketik "show ip bgp"
• Pastikan route yang di advrtise ke BGP masuk dalam routing tabelnya, ketik "show ip route bgp"
• Pastikan IP Loopback R1 dan R2 bisa saling diping oleh keduanya

KONFIGURASI :

Hapus konfigurasi bgp sebelumnya

R1(config)#no router bgp 12

R2(config)#no router bgp 12

Agar loopbacknya bisa diping, gunakan IGP (RIP, OSPF, EIGRP) ataupun static route

R1(config)#router rip
R1(config-router)#net 1.0.0.0
R1(config-router)#net 12.0.0.0

R2(config)#router rip
R2(config-router)#net 2.0.0.0
R2(config-router)#net 12.0.0.0

Pastikan ip loopbacknya bisa diping dulu

R1#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 = 48/72/104 ms

R2#ping 1.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/49/80 ms

Konfigurasi BGP peernya dengan menambahkan update-source loopback 0,bila tidak ditambahkan baris tersebut, maka yang digunakan updatenya adalah ip interface physical sehingga bgp adjacency nya akan bermasalah.

R1(config)#router bgp 12
R1(config-router)#neighbor 2.2.2.2 remote-as 12
R1(config-router)#neighbor 2.2.2.2 update-source loopback1

R2(config)#router bgp 12
R2(config-router)#neighbor 1.1.1.1 remote-as 12
R2(config-router)#neighbor 1.1.1.1 update-source loopback1

Pastikan BGP adjacency nya sudah up

R1#sh ip bgp summary
BGP router identifier 1.1.1.1, local AS number 12
BGP table version is 1, main routing table version 1

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2.2.2.2         4    12       3       3        1    0    0 00:00:36        0 

Pastikan pada bagian state/pfxRcd nya bernilai 0 dan perhatikan juga ip neighbornya bukan lagi ip physicalnya melainkan ip loopbacknya.

Selanjutnya buat ip loopback baru untuk diadvertise ke bgp

R1(config)#int lo0
R1(config-if)#ip add 11.11.11.11 255.255.255.255
R1(config-if)#router bgp 12
R1(config-router)#net 11.11.11.11 mask 255.255.255.255

R2(config)#int lo0
R2(config-if)#ip add 22.22.22.22 255.255.255.255
R2(config-if)#router bgp 12
R2(config-router)#net 22.22.22.22 mask 255.255.255.255

Pastikan route tersebut sudah di advertise sehingga nilai state/pfxRcd nya menjadi 1

R1#sh ip bgp summary
BGP router identifier 1.1.1.1, local AS number 12
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
3/2 BGP path/bestpath attribute entries using 372 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
Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory
BGP using 748 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
2.2.2.2         4    12      10      10        3    0    0 00:06:44        1

Cek route yang diadvertise ke bgp. 

R1#sh ip bgp
BGP table version is 3, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 11.11.11.11/32   0.0.0.0                  0         32768 i
*>i22.22.22.22/32   2.2.2.2                  0    100      0 i
R1#

Cek routing tabelnya.

R1#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 not set

     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback1
R    2.0.0.0/8 [120/1] via 12.12.12.2, 00:00:14, FastEthernet0/0
     22.0.0.0/32 is subnetted, 1 subnets
B       22.22.22.22 [200/0] via 2.2.2.2, 00:03:09
     11.0.0.0/32 is subnetted, 1 subnets
C       11.11.11.11 is directly connected, Loopback0
     12.0.0.0/24 is subnetted, 1 subnets
C       12.12.12.0 is directly connected, FastEthernet0/0