Thursday, March 27, 2014

Cisco BGP 4

Cisco BGP 4



Table of Content
  • BGP Overview
  • Konfigurasi BGP Antara 2 AS
    • Topologi
    • Konfigurasi IP Address
    • Konfigurasi BGP pada AS 4845
    • Konfigurasi BGP pada AS 4844
    • Verifikasi BGP
  • Referensi

BGP Overview

BGP (Border Gateway Protocol) merupakan protokol yang dipergunakan untuk pertukaran informasi routing antara 2 AS. BGP merupakan protokol standar untuk exterior gateway protocol yang terbanyak digunakan di internet. AS (Autonomous System) merupakan jaringan dengan ip - ip publik yang berada di bawah pengelolaan 1 manajemen, misalnya suatu isp.

Konfigurasi BGP Antara 2 AS

Sebagai contoh kali ini kita akan melakukan konfigurasi bgp antara 2 AS : AS 4844 dan AS4845 di mana kita akan melakukan 2 konfigurasi ebgp (external bgp peering) pada masing masing edge router kedua AS dan 2 konfigurasi ibgp (internal bgp peering) pada kedua router di dalam jaringan masing masing AS.

Topologi

Berikut ini adalah topologi yang akan kita gunakan :


Pada topologi di atas, kita memiliki 2 buah AS : AS 4845 dan AS 4844. Router 2107 merupakan internal bgp peering di dalam AS 4845, Router 2101 merupakan edge router (external bgp peering) pada AS 4845. Pada AS 4844 kita memiliki 2 buah router : Router 2101 merupakan edge router (external bgp peering) pada AS 4844, Router 2106 merupakan internal bgp peering pada AS 4844.
Konfigurasi IP Address (Assign ip address to interfaces)

Konfigurasi pada Router 2107 (Internal BGP Peer AS 4845): 
2107#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
2107(config)#interface FastEthernet1/0
2107(config-if)#ip address 192.168.0.1 255.255.255.0
2107(config-if)#duplex auto
2107(config-if)# speed auto

Konfigurasi ip address pada Edge Router 2101 (External BGP Peer AS 4845): 
2101#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
2101(config)#interface FastEthernet1/0
2101(config-if)#ip address 192.168.0.2 255.255.255.0
2101(config-if)#duplex auto
2101(config-if)#speed auto
Konfigurasi interface yang berhubungan dengan AS 4844 
2101(config-if)#interface Serial0/0
2101(config-if)#ip address 202.79.197.232 255.255.255.0
2101(config-if)#serial restart-delay 0

Konfigurasi ip address pada edge router 2102 (external bgp peering AS 4844): 
2102#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
2102(config)#interface FastEthernet1/0
2102(config-if)#ip address 172.168.1.2 255.255.255.0
2102(config-if)#duplex auto
2102(config-if)#speed auto
Konfigurasi pada interface yang berhubungan dengan AS 4845 : 
2102(config-if)#interface Serial0/0
2102(config-if)#ip address 202.79.197.132 255.255.255.0
2102(config-if)#serial restart-delay 0

Konfigurasi ip address pada router 2106 (internal bgp peering AS 4845): 
2106#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
2106(config)#interface FastEthernet1/0
2106(config-if)#ip address 172.168.1.1 255.255.255.0
2106(config-if)#duplex auto
2106(config-if)#speed auto

Konfigurasi BGP AS 4845

Konfigurasi BGP pada router 2107 (AS 4845) : 
2107(config)#router bgp 4845
2107(config-router)#no synchronization
2107(config-router)#bgp log-neighbor-changes
2107(config-router)#network 192.168.0.0
2107(config-router)#neighbor 192.168.0.2 remote-as 4845
2107(config-router)#no auto-summary

Konfigurasi BGP pada router 2101 (AS 4845): 
2101(config)#router bgp 4845
2101(config-router)#no synchronization
2101(config-router)#bgp log-neighbor-changes
2101(config-router)#network 192.168.0.0
2101(config-router)#network 202.79.197.0
2101(config-router)#neighbor 192.168.0.1 remote-as 4845
2101(config-router)#neighbor 192.168.0.1 next-hop-self
2101(config-router)#neighbor 202.79.197.132 remote-as 4844
2101(config-router)#neighbor 202.79.197.132 next-hop-self
2101(config-router)#no auto-summary

Konfigurasi BGP AS 4844

Konfigurasi BGP pada edge router 2102 (AS 4844) : 
2102(config)#router bgp 4844
2102(config-router)#no synchronization
2102(config-router)#bgp log-neighbor-changes
2102(config-router)#network 172.168.1.0 mask 255.255.255.0
2102(config-router)#network 202.79.197.0
2102(config-router)#neighbor 172.168.1.1 remote-as 4844
2102(config-router)#neighbor 172.168.1.1 next-hop-self
2102(config-router)#neighbor 202.79.197.232 remote-as 4845
2102(config-router)#neighbor 202.79.197.232 next-hop-self
2102(config-router)#no auto-summary

Konfigurasi BGP pada router 2106 (AS 4844): 
2106(config)#router bgp 4844
2106(config-if)#no synchronization
2106(config-if)#bgp log-neighbor-changes
2106(config-if)#network 172.168.1.0 mask 255.255.255.0
2106(config-if)#neighbor 172.168.1.2 remote-as 4844
2106(config-if)#no auto-summary

Pada konfigurasi di atas pada dasarnya hanya ada 2 jenis konfigurasi yaitu konfigurasi pada internal bgp peer dan konfigurasi pada eksternal bgp peer. Sebagai contoh akan diambil konfig pada ibgp dan ebgp pada AS 4845
Konfigurasi Internal BGP Peer pada AS 4845
 
  • router bgp 4845 digunakan untuk melakukan setup bgp peering pada router tersebut dengan nomor as 4845.
  • network digunakan untuk menentukan range ip yang akan diperkenalkan ke neigbor.
  • neighbor 192.168.0.2 remote-as 4845, digunakan untuk menambahkan bgp neigbor yang berhubungan langsung dengan router ini di sini menggunakan remote as yang sama yaitu 4845 (internal bgp peering).
  • no synchronization, di sini synchronization kita disable karena AS 4845 tidak akan melewatkan traffik ke AS lain.
  • no auto-summary, digunakan untuk penentuan ip range berdasarkan cidr (mendisable class based), jika penentuan berdasarkan class based ip address didisable maka penentuan network mask berdasarkan cidr akan memilih secara otomatis network range berdasarkan longest prefix match.

Konfigurasi Eksternal BGP Peer pada AS 4845
 
  • router bgp 4845 digunakan untuk melakukan setup bgp peering pada router tersebut dengan nomor as 4845.
  • pada contoh di atas perintah network digunakan untuk melakukan broadcast ip range yang ingin diperkenalkan pada peer lainya.
  • neighbor 192.168.0.2 remote-as 4845, menambahkan neighbor dengan ip 192.168.0.1 dengan as lokal 4845, neighbor 202.79.197.132 remote-as 4844 menambahkan neighbor dengan ip 202.79.197.132 dengan AS luar 4844.
  • pada konfig di atas diperkenalkan perintah next-hop-self agar router bisa melewatkan trafik dari neigbor 192.168.0.1 ke neighbor 202.79.197.132 dan sebaliknya.

Verifikasi BGP

Verifikasi bgp pada router 2107: 
2107#sh ip bgp summary
BGP router identifier 192.168.0.1, local AS number 4845
BGP table version is 4, main routing table version 4
3 network entries using 303 bytes of memory
4 path entries using 192 bytes of memory
3 BGP path attribute entries using 180 bytes of memory
1 BGP AS-PATH entries using 24 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 699 total bytes of memory
BGP activity 3/0 prefixes, 4/0 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
192.168.0.2     4  4845      93      93        4    0    0 01:28:54        3
2107#sh ip bgp
BGP table version is 4, local router ID is 192.168.0.1
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
*>i172.168.1.0/24   192.168.0.2              0    100      0 4844 i
* i192.168.0.0      192.168.0.2              0    100      0 i
*>                  0.0.0.0                  0         32768 i
*>i202.79.197.0     192.168.0.2              0    100      0 i

Verifikasi bgp pada router 2101: 
2101#sh ip bgp summary
BGP router identifier 202.79.197.232, local AS number 4845
BGP table version is 4, main routing table version 4
3 network entries using 351 bytes of memory
5 path entries using 260 bytes of memory
4/2 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 1131 total bytes of memory
BGP activity 3/0 prefixes, 5/0 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
192.168.0.1     4  4845      97      97        4    0    0 01:32:08        1
202.79.197.132  4  4844      96      96        4    0    0 01:32:04        2
2101#sh ip bgp
BGP table version is 4, local router ID is 202.79.197.232
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
*> 172.168.1.0/24   202.79.197.132           0             0 4844 i
* i192.168.0.0      192.168.0.1              0    100      0 i
*>                  0.0.0.0                  0         32768 i
*  202.79.197.0     202.79.197.132           0             0 4844 i
*>                  0.0.0.0                  0         32768 i

Verifikasi pada router 2102 : 
2102#sh ip bgp summary
BGP router identifier 202.79.197.132, local AS number 4844
BGP table version is 4, main routing table version 4
3 network entries using 351 bytes of memory
5 path entries using 260 bytes of memory
4/2 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 1131 total bytes of memory
BGP activity 3/0 prefixes, 5/0 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
172.168.1.1     4  4844      97      97        4    0    0 01:32:55        1
202.79.197.232  4  4845      96      96        4    0    0 01:32:52        2
2102#sh ip bgp
BGP table version is 4, local router ID is 202.79.197.132
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
* i172.168.1.0/24   172.168.1.1              0    100      0 i
*>                  0.0.0.0                  0         32768 i
*> 192.168.0.0      202.79.197.232           0             0 4845 i
*  202.79.197.0     202.79.197.232           0             0 4845 i
*>                  0.0.0.0                  0         32768 i

Verifikasi pada router 2106: 
2106#sh ip bgp summary
BGP router identifier 172.168.1.1, local AS number 4844
BGP table version is 4, main routing table version 4
3 network entries using 303 bytes of memory
4 path entries using 192 bytes of memory
3 BGP path attribute entries using 180 bytes of memory
1 BGP AS-PATH entries using 24 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 699 total bytes of memory
BGP activity 3/0 prefixes, 4/0 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
172.168.1.2     4  4844      99      99        4    0    0 01:34:02        3
2106#sh ip bgp
BGP table version is 4, local router ID is 172.168.1.1
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
* i172.168.1.0/24   172.168.1.2              0    100      0 i
*>                  0.0.0.0                  0         32768 i
*>i192.168.0.0      172.168.1.2              0    100      0 4845 i
*>i202.79.197.0     172.168.1.2              0    100      0 i

Pengujian ping dari internal bgp peer AS 4845 ke AS 4844 :

Pengujian ping dari internal bgp peer AS 4844 ke AS 4845 :

Referensi



Thanks to : Zico, Eki, Ega, Edward, Gunslinger and all my brothers out there.

written by : Antonius (ringlayer)
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