BGP

Border Gateway Protocol disingkat BGP adalah inti dari protocol routing internet.

Protocol ini yang menjadi backbone dari jaringan Internet dunia. BGP adalah protokol routing inti dari Internet yg digunakan untuk melakukan pertukaran informasi routing antar jaringan.

BGP dijelaskan dalam RFC4271. BGP bekerja dengan cara memetakan sebuah tabel IP network yang menunjuk ke jaringan yg dapat dicapai antar AS (Autonomous System). Hal ini digambarkan sebagai sebuah protocol path vector.  BGP tidak menggunakan metrik IGP(Interior Gateway Protocol) tradisional, tapi membuat routing decision berdasarkan path, network policies, dan atau ruleset.

BGP mendukung Class Inter-Domain Routing dan menggunakan route aggregation untuk mengurangi ukuran tabel routing. BGP diciptakan untuk menggantikan protokol routing EGP yang mengijinkan routing secara tersebar sehingga tidak harus mengacu pada satu jaringan backbone saja.

Attribute dari BGP ada beberapa yaitu :

1. Weight (tertinggi )
2. Local Preference (tertinggi)
3. Locally Originated
4. AS-Path (terendah)
5. Origin (IGP > EGP > ?)
6. MED  (terendah)

Setelah penjelasan di atas berikut beberapa lab yang terkait dengan BGP, terutama BGP di dunia CCIE RS.

• iBGP Peering

Konfigurasi Dasar :

R1(config)#int fa0/0

R1(config-if)#ip add 12.12.12.1 255.255.255.0

R1(config-if)#no sh

R1(config-router)#int lo 0

R1(config-if)#ip add 1.1.1.1 255.255.255.255

R1(config-if)#router bgp 12

R1(config-router)#nei 12.12.12.2 remote-as 12

R1(config-router)#net 1.1.1.1 mask 255.255.255.255

Lakukan konfigurasi yang sama juga untuk router kedua, dengan menggunakan loopback 2.2.2.2/32.

Cek route table :

R1#sh ip bgp sum

BGP router identifier 12.12.12.1, 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

12.12.12.2      4    12       7       7        3    0    0 00:03:27        1

Cek route table :

R1#sh ip bgp

BGP table version is 3, local router ID is 12.12.12.1

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

*> 1.1.1.1/32       0.0.0.0                  0         32768 i

*>i2.2.2.2/32       12.12.12.2               0    100      0 i

R1#sh ip route bgp

2.0.0.0/32 is subnetted, 1 subnets

B       2.2.2.2 [200/0] via 12.12.12.2, 00:07:25

Cek ping :

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 = 28/47/64 ms

 

• IBGP Peering  – Loopback

Topologi yang digunakan masih sama dengan lab di atas.

command network dan neighbor di router bgp dihapus kemudian tambahkan command berikut :

R2(config)#router rip

R2(config-router)#ver 2

R2(config-router)#net 2.0.0.0

R2(config-router)#net 12.0.0.0

R2(config-router)#exit

R2(config)#router bgp 12

R2(config-router)#nei 1.1.1.1 remote 12

R2(config-router)#nei 1.1.1.1 update-source lo0

Lalu tambahkan subnet baru kedalam router bgp :

R2(config-if)#int lo1

R2(config-if)#ip add 22.22.22.22 255.255.255.255

R2(config-if)#no sh

R2(config-if)#router bgp 12

R2(config-router)#net 22.22.22.22 mask 255.255.255.255

Cek ping :

R1#ping 22.22.22.22

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 22.22.22.22, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 28/59/104 ms

R1#sh ip bgp sum

BGP router identifier 12.12.12.1, local AS number 12

BGP table version is 7, main routing table version 7

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 2) using 32 bytes of memory

BGP using 748 total bytes of memory

BGP activity 4/2 prefixes, 4/2 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd

2.2.2.2         4    12       7       7        7    0    0 00:02:07        1

R1#sh ip bgp

BGP table version is 7, local router ID is 12.12.12.1

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#sh ip route bgp

22.0.0.0/32 is subnetted, 1 subnets

B       22.22.22.22 [200/0] via 2.2.2.2, 00:00:33

 

• eBGP Peering

konfigurasi untuk eBGP peering :

R2(config)#int lo0

R2(config-if)#ip add 2.2.2.2 255.255.255.255

R2(config-if)#no sh

R2(config-if)#int s0/0

R2(config-if)#ip add 23.23.23.2 255.255.255.0

R2(config-if)#no sh

R2(config-if)#router bgp 12

R2(config-router)#nei 23.23.23.3 remote 3

R2(config-router)#net 2.2.2.2 mask 255.255.255.255

Lakukan hal yang sama pada router R3 dengan menggunakan loopback 3.3.3.3/32.

Cek ping :

R2#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 = 12/39/76 ms

Cek route table :

R2#sh ip bgp sum

BGP router identifier 2.2.2.2, 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

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

Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory

BGP using 772 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

23.23.23.3      4     3       7       7        3    0    0 00:03:42        1

R2#sh ip bgp

BGP table version is 3, local router ID is 2.2.2.2

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

*> 2.2.2.2/32       0.0.0.0                  0         32768 i

*> 3.3.3.3/32       23.23.23.3               0             0 3 i

 

• eBGP – Loopback – eBGP Multihop

Topologi yang dipakai sama dengan lab sebelumnya.

konfigurasi berikut :

R2(config)#router eigrp 2

R2(config-router)#net 23.23.23.0 0.0.0.255

R2(config-router)#net 2.2.2.2 0.0.0.0

R2(config)#router bgp 12

R2(config-router)#nei 3.3.3.3 remote-as 3

R2(config-router)#nei 3.3.3.3 update-source lo0

R2(config-router)#nei 3.3.3.3 ebgp-multihop

Lakukan hal yang sama untuk R3 dan tambahkan int lo1 di R2 :

R2(config)#int lo1

R2(config-if)#ip add 22.22.22.22 255.255.255.255

R2(config-if)#no sh

R2(config-if)#router bgp 12

R2(config-router)#net 22.22.22.22 mask 255.255.255.255

Cek ping :

R3#ping 22.22.22.22

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 22.22.22.22, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/30/80 ms

Cek route table :

R3#sh ip bgp

BGP table version is 7, local router ID is 3.3.3.3

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

*> 22.22.22.22/32   2.2.2.2                  0             0 12 i

*> 33.33.33.33/32   0.0.0.0                  0         32768 i

 

• BGP Next-Hop-Self

Masih sama dengan topologi sebelumnya.

Konfigurasikan iBGP peering antara router R1 dan R2.

cek route table :

R1(config-router)#do sh ip bgp

BGP table version is 4, local router ID is 11.11.11.11

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

*>i22.22.22.22/32   2.2.2.2                  0    100      0 i

*>i33.33.33.33/32   3.3.3.3                  0    100      0 3 i

disini terlihat bahwa ip loopback 1 R3 diterima oleh R1 lewat ip address loopback 0 R3. Hal ini salah karena ip address lo0 R3 seharusnya tidak bisa direach oleh R1.

maka tambahkan command berikut :

R2(config)#router bgp 12

R2(config-router)#nei 1.1.1.1 next-hop-self

Cek route table :

R1(config-router)#do sh ip bgp

BGP table version is 5, local router ID is 11.11.11.11

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

*>i22.22.22.22/32   2.2.2.2                  0    100      0 i

*>i33.33.33.33/32   2.2.2.2                  0    100      0 3 i

Cek ping :

R1(config-router)#do ping 33.33.33.33

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 33.33.33.33, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 28/52/116 ms

 

• BGP Authentication

Masih dengan topologi yang sama seperti sebelumnya.

BGP hanya support autentikasi dengan menggunakan MD5 saja.

Konfigurasinya :

R2(config-router)#router bgp 12

R2(config-router)#nei 1.1.1.1 password 0 RAHASIA

R1(config-router)#router bgp 12

R1(config-router)#nei 2.2.2.2 password 0 RAHASIA

 

• BGP Route Reflector

Hilangkan konfigurasi next-hop-self dari R3, karena akan dilakukan route reflector.

Konfigurasi di R1, R2 dan R3.

R1(config-router)#router bgp 12

R1(config-router)#nei 2.2.2.2 remote 12

R1(config-router)#nei 2.2.2.2 update lo0

R1(config-router)#nei 2.2.2.2 route-reflector-client

R1(config-router)#nei 3.3.3.3 remote 12

R1(config-router)#nei 3.3.3.3 update lo0

R1(config-router)#nei 3.3.3.3 route-reflector-client

R2(config-router)#router bgp 12

R2(config-router)#nei 1.1.1.1 remote 12

R2(config-router)#nei 1.1.1.1 update lo0

R3(config-router)#router bgp 12

R3(config-router)#nei 1.1.1.1 remote 12

R3(config-router)#nei 1.1.1.1 update lo0

Cek route table :

R1#sh ip bgp sum

BGP router identifier 11.11.11.11, local AS number 12

BGP table version is 4, main routing table version 4

3 network entries using 360 bytes of memory

3 path entries using 156 bytes of memory

3/2 BGP path/bestpath attribute entries using 372 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

Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory

BGP using 944 total bytes of memory

BGP activity 3/0 prefixes, 3/0 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd

2.2.2.2         4    12       5       7        4    0    0 00:01:12        1

3.3.3.3         4    12       6       7        4    0    0 00:00:35        2

Cek ping :

R1#ping 44.44.44.44

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 44.44.44.44, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 60/138/224 ms

 

• BGP Confederation

 

R1, R2,R3,R4 dan R5 menggunakan AS 12, dan R6 menggunakan AS 3.

R1 dan R4 menggunakan AS Confederation 12001, R2 dan R5 menggunakan AS confederation 12002, dan R3 menggunakan AS Confederation 12003.

Konfigurasi R1 :

interface Loopback0

ip address 1.1.1.1 255.255.255.255

!

interface FastEthernet0/0

ip address 12.12.12.1 255.255.255.0

!

interface FastEthernet0/1

ip address 14.14.14.1 255.255.255.0

!

router bgp 12001

bgp log-neighbor-changes

bgp confederation identifier 12

bgp confederation peers 12002

network 1.1.1.1 mask 255.255.255.255

neighbor 12.12.12.2 remote-as 12002

neighbor 14.14.14.4 remote-as 12001

neighbor 14.14.14.4 next-hop-self

Konfigurasi R4 :

interface Loopback0

ip address 4.4.4.4 255.255.255.255

!

interface FastEthernet0/0

ip address 14.14.14.4 255.255.255.0

!

router bgp 12001

no synchronization

bgp log-neighbor-changes

bgp confederation identifier 12

network 4.4.4.4 mask 255.255.255.255

neighbor 14.14.14.1 remote-as 12001

Konfigurasi R2 :

interface Loopback0

ip address 2.2.2.2 255.255.255.255

!

interface FastEthernet0/0

ip address 12.12.12.2 255.255.255.0

!

interface Serial0/0

ip address 25.25.25.2 255.255.255.0

!

interface FastEthernet0/1

ip address 23.23.23.2 255.255.255.0

!

router bgp 12002

bgp log-neighbor-changes

bgp confederation identifier 12

bgp confederation peers 12001 12003

network 2.2.2.2 mask 255.255.255.255

neighbor 12.12.12.1 remote-as 12001

neighbor 23.23.23.3 remote-as 12003

neighbor 25.25.25.5 remote-as 12002

neighbor 25.25.25.5 next-hop-self

Konfigurasi R5 :

interface Loopback0

ip address 5.5.5.5 255.255.255.255

!

interface Serial0/0

ip address 25.25.25.5 255.255.255.0

!

router bgp 12002

bgp log-neighbor-changes

bgp confederation identifier 12

network 5.5.5.5 mask 255.255.255.255

neighbor 25.25.25.2 remote-as 12002

Konfigurasi R3:

interface Loopback0

ip address 3.3.3.3 255.255.255.255

!

interface FastEthernet0/0

ip address 23.23.23.3 255.255.255.0

!

interface Serial0/0

ip address 36.36.36.3 255.255.255.0

!

router bgp 12003

bgp log-neighbor-changes

bgp confederation identifier 12

bgp confederation peers 12002

network 3.3.3.3 mask 255.255.255.255

neighbor 23.23.23.2 remote-as 12002

neighbor 36.36.36.6 remote-as 3

Konfigurasi R6 :

interface Loopback0

ip address 6.6.6.6 255.255.255.255

!

interface Serial0/0

ip address 36.36.36.6 255.255.255.0

!

router bgp 3

network 6.6.6.6 mask 255.255.255.255

neighbor 36.36.36.3 remote-as 12

Cek route table :

R2#sh ip bgp

BGP table version is 6, local router ID is 2.2.2.2

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

*> 1.1.1.1/32       12.12.12.1               0    100      0 (12001) i

*> 2.2.2.2/32       0.0.0.0                  0         32768 i

*> 3.3.3.3/32       23.23.23.3               0    100      0 (12003) i

*  4.4.4.4/32       14.14.14.4               0    100      0 (12001) i

*>i5.5.5.5/32       25.25.25.5               0    100      0 i

*  6.6.6.6/32       36.36.36.6               0    100      0 (12003) 3 i

Dari show ip bgp dapat dilihat bahwa 6.6.6.6 masih berstatus unreachable dari R2.

Mari tambahkan route ke 36.36.36.6 dari R2:

ip route 36.36.36.0 255.255.255.0 23.23.23.3

Cek route table :

R2#sh ip bgp

BGP table version is 6, local router ID is 2.2.2.2

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

*> 1.1.1.1/32       12.12.12.1               0    100      0 (12001) i

*> 2.2.2.2/32       0.0.0.0                  0         32768 i

*> 3.3.3.3/32       23.23.23.3               0    100      0 (12003) i

*  4.4.4.4/32       14.14.14.4               0    100      0 (12001) i

*>i5.5.5.5/32       25.25.25.5               0    100      0 i

*> 6.6.6.6/32       36.36.36.6               0    100      0 (12003) 3 i

 

• BGP Atribute (Origin)

Konfigurasinya :

R1 :

interface Loopback0

ip address 1.1.1.1 255.255.255.255

!

interface FastEthernet0/0

ip address 12.12.12.1 255.255.255.0

!

router bgp 100

network 1.1.1.1 mask 255.255.255.255

neighbor 12.12.12.2 remote-as 200

R2 :

interface Loopback0

ip address 2.2.2.2 255.255.255.255

!

interface FastEthernet0/0

ip address 12.12.12.2 255.255.255.0

!

interface Serial0/0

ip address 23.23.23.2 255.255.255.0

!

router bgp 200

network 2.2.2.2 mask 255.255.255.255

redistribute static

neighbor 12.12.12.1 remote-as 100

neighbor 23.23.23.3 remote-as 200

R3 :

interface Loopback0

ip address 3.3.3.3 255.255.255.255

!

interface Loopback1

ip address 33.33.33.33 255.255.255.255

!

interface Loopback2

ip address 30.30.30.30 255.255.255.255

!

interface Serial0/0

ip address 23.23.23.3 255.255.255.0

!

router eigrp 1

network 33.33.33.33 0.0.0.0

!

router bgp 200

network 3.3.3.3 mask 255.255.255.255

redistribute eigrp 1

neighbor 23.23.23.2 remote-as 200

Cek route table :

R1#sh ip bgp

BGP table version is 6, 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

*> 1.1.1.1/32       0.0.0.0                  0         32768 i

*> 2.2.2.2/32       12.12.12.2               0             0 200 i

*> 3.3.3.3/32       12.12.12.2                             0 200 i

*> 30.30.30.30/32   12.12.12.2               0             0 200 ?

*> 33.33.33.33/32   12.12.12.2                             0 200 ?

 

• BGP Attribute (Community)

Konfigurasikan access list sehingga ip address 11.11.11.11 di R1 tidak diadvertise di R4.

Konfigurasi R1:

R1(config)#access-list 1 permit host 11.11.11.11

R1(config)#route-map NO-EXPORT

R1(config-route-map)#match ip address 1

R1(config-route-map)#set community no-export

R1(config-route-map)#router bgp 123

R1(config-router)#nei 2.2.2.2 route-map NO-EXPORT out

R1(config-router)#nei 2.2.2.2 send-community

Cek route table :

R4#sh ip bgp

BGP table version is 6, local router ID is 4.4.4.4

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

*> 4.4.4.4/32       0.0.0.0                  0         32768 i

*> 22.22.22.22/32   24.24.24.2               0             0 123 i

*> 33.33.33.33/32   24.24.24.2                             0 123 i

Selanjutnya skenarionya adalah membuat ip 33.33.33.33 di R3 tidak diadvertise lagi di R1, dan R4.

Konfigurasi di R3 :

R3(config)#access-list 1 permit host 33.33.33.33

R3(config)#route-map NO-ADVERTISE

R3(config-route-map)#match ip address 1

R3(config-route-map)#set community no-advertise

R3(config-route-map)#router bgp 123

R3(config-router)#nei 2.2.2.2 route-map NO-ADVERTISE out

R3(config-router)#nei 2.2.2.2 send-community

Cek route table :

R4#sh ip bgp

BGP table version is 7, local router ID is 4.4.4.4

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

*> 4.4.4.4/32       0.0.0.0                  0         32768 i

*> 22.22.22.22/32   24.24.24.2               0             0 123 i

Cek route table :

R1#sh ip bgp

BGP table version is 6, local router ID is 11.11.11.11

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

*>i4.4.4.4/32       2.2.2.2                  0    100      0 4 i

*> 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

Selanjutnya untuk skenario local AS :

Konfigurasi di R1 :

R1#router bgp 12

bgp confederation identifier 123

network 11.11.11.11 mask 255.255.255.255

neighbor 2.2.2.2 remote-as 12

neighbor 2.2.2.2 update-source Loopback0

Konfigurasi di R2 :

R2#router bgp 12

bgp confederation identifier 123

bgp confederation peers 3

network 22.22.22.22 mask 255.255.255.255

neighbor 1.1.1.1 remote-as 12

neighbor 1.1.1.1 update-source Loopback0

neighbor 1.1.1.1 next-hop-self

neighbor 3.3.3.3 remote-as 3

neighbor 3.3.3.3 ebgp-multihop 255

neighbor 3.3.3.3 update-source Loopback0

neighbor 3.3.3.3 next-hop-self

neighbor 24.24.24.4 remote-as 4

Konfigurasi di R3 :

R3#router bgp 3

bgp confederation identifier 123

bgp confederation peers 12

network 33.33.33.33 mask 255.255.255.255

neighbor 2.2.2.2 remote-as 12

neighbor 2.2.2.2 ebgp-multihop 255

neighbor 2.2.2.2 update-source Loopback0

Selanjutnya filter ip address 11.11.11.11 di R1 agar tidak diterima di R3

R1(config)#access-list 1 permit host 11.11.11.11

R1(config)#route-map LOCAL-AS permit 10

R1(config-route-map)#match ip address 1

R1(config-route-map)#set community local-AS

R1(config-route-map)#router bgp 12

R1(config-router)#nei 2.2.2.2 route-map LOCAL-AS out

R1(config-router)#nei 2.2.2.2 send-community

Cek route table :

R3#sh ip bgp

BGP table version is 6, local router ID is 33.33.33.33

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

*> 4.4.4.4/32       2.2.2.2                  0    100      0 (12) 4 i

*> 22.22.22.22/32   2.2.2.2                  0    100      0 (12) i

*> 33.33.33.33/32   0.0.0.0                  0         32768 i

 

• BGP Peers Group

skenario selanjutnya adalah untuk menghemat jumlah command line yang harus dituliskan ke dalam CLI.

Konfigurasinya :

router bgp 123

nei INTERNAL peer group

nei INTERNAL remote-as 123

nei INTERNAL update-source lo0

nei 2.2.2.2 peer-group INTERNAL

nei 3.3.3.3 peer-group INTERNAL

 

• BGP Aggregator

Skenario selanjutnya adalah untuk melakukan summary address dari beberapa IP yang ada di show ip route .

Konfigurasinya sbb :

router bgp x

aggregate-address x.x.x.x

Bila dibutuhkan hanya beberapa ip address saja yang ingin dihilangkan maka konfigurasinya sbb :

access-list 1 permit host x.x.x.x

route-map BLOK

match ip address 1

router bgp 4

aggregate-address x.x.x.x suppress-map BLOK

 

• BGP Local-AS

Konfigurasinya sbb :

router bgp 3

neighbor x.x.x.x local-as yyy

Jika ingin melakukan no prepend local-as konfigurasinya sbb :

neighbor x.x.x.x local-as yyy no-prepend

Jika ingin no prepend dan replace as konfigurasinya sbb :

neighbor x.x.x.x local-as yyy no-prepend replace-as