Cisco: BGP 2 BGP redistribute 2 OSPF
Ada tiga (3) ISP
ISP1:
IP 192.168.1.1/24 menuju ISP3 IP 192.168.3.1/24 menuju ISP2 AS 10 IP 10.100.100.0/24 IP 10.100.200.0/24
ISP3 (kita)
IP 192.168.1.2/24 - menuju ISP1 IP 192.168.2.2/24 - menuju ISP2 AS 30 IP 10.1.1.0/24 IP 10.1.2.0/24
R4
IP 10.1.1.2/24 menuju ISP3 IP 172.16.1.1 menuju R5 IP 172.16.10.1 LAN IP 172.16.20.1 LAN
R5
IP 10.1.2.2/24 menuju ISP3 IP 172.16.1.2 menuju R4 IP 172.16.100.1/24 LAN IP 172.16.200.1/24 LAN
Sambungan Fisik
ISP1
ISP1 Eth1/0 -> ISP3 Eth1/0 ISP1 Eth1/1 -> ISP2 Eth1/1 ISP2 Eth1/0 -> ISP3 Eth1/1 ISP1 Eth1/2 10.100.100.1/24 ISP1 Eth1/3 10.100.200.1/24 ISP2 Eth1/2 10.10.10.1/24 ISP2 Eth1/3 10.10.20.1/24 ISP3 Eth1/2 10.1.1.1/24 ISP3 Eth1/3 10.1.2.1/24
R4 Eth1/0 -> ISP3 Eth1/2 R5 Eth1/0 -> ISP3 Eth1/3 R4 Eth1/1 -> R5 Eth1/1
Setup connection
ISP1
enable configure terminal interface Ethernet1/0 ip address 192.168.1.1 255.255.255.0 no shutdown exit interface Ethernet1/1 ip address 192.168.3.1 255.255.255.0 no shutdown exit interface Ethernet1/2 ip address 10.100.100.1 255.255.255.0 no shutdown exit interface Ethernet1/3 ip address 10.100.200.1 255.255.255.0 no shutdown exit end
ISP3
enable configure terminal interface Ethernet1/0 ip address 192.168.1.2 255.255.255.0 no shutdown exit interface Ethernet1/1 ip address 192.168.2.2 255.255.255.0 no shutdown exit interface Ethernet1/2 ip address 10.1.1.1 255.255.255.0 no shutdown exit interface Ethernet1/3 ip address 10.1.2.1 255.255.255.0 no shutdown exit end
R4
enable configure terminal interface Ethernet1/0 ip address 10.1.1.2 255.255.255.0 no shutdown exit interface Ethernet1/1 ip address 172.16.1.1 255.255.255.0 no shutdown exit interface Ethernet1/2 ip address 172.16.10.1 255.255.255.0 no shutdown exit interface Ethernet1/3 ip address 172.16.20.1 255.255.255.0 no shutdown exit end
R5
enable configure terminal interface Ethernet1/0 ip address 10.1.2.2 255.255.255.0 no shutdown exit interface Ethernet1/1 ip address 172.16.1.2 255.255.255.0 no shutdown exit interface Ethernet1/2 ip address 172.16.100.1 255.255.255.0 no shutdown exit interface Ethernet1/3 ip address 172.16.200.1 255.255.255.0 no shutdown exit end
BGP Peering
Consider that IP connectivity between ISPs edge routers and Our Core router is already set up and working properly. So we can start to establish BGP peering to both ISPs.
ISP1:
enable configure terminal router bgp 10 bgp router-id 192.168.1.1 network 10.100.100.0 mask 255.255.255.0 network 10.100.200.0 mask 255.255.255.0 neighbor 192.168.1.2 remote-as 30 end
Main / Backup Link Setup di ISP3
Lakukan
- accept network kita sendiri
- drop semua tabel IP lainnya, karena kita tidak mau menjadi transit provider
- BGP AS prepend - menaikan AS path ke salah satu ISP (disini ISP1)
ISP3:
enable configure terminal router bgp 30 bgp router-id 192.168.1.2 no synchronization bgp log-neighbor-changes network 10.1.1.0 mask 255.255.255.0 network 10.1.2.0 mask 255.255.255.0 neighbor 192.168.1.1 remote-as 10 redistribute ospf 3 metric 100 end
OSPF
ISP3
enable configure terminal ! ! area 0 = backbone router ospf 3 network 10.1.1.0 0.0.0.255 area 0.0.0.0 network 10.1.2.0 0.0.0.255 area 0.0.0.0 end
R4
enable configure terminal ! ! area 0 = backbone router ospf 4 network 10.1.1.0 0.0.0.255 area 0.0.0.0 network 172.16.1.0 0.0.0.255 area 0.0.0.0 network 172.16.10.0 0.0.0.255 area 0.0.0.0 network 172.16.20.0 0.0.0.255 area 0.0.0.0 end
R5
enable configure terminal ! ! area 0 = backbone router ospf 5 network 10.1.2.0 0.0.0.255 area 0.0.0.0 network 172.16.1.0 0.0.0.255 area 0.0.0.0 network 172.16.100.0 0.0.0.255 area 0.0.0.0 network 172.16.200.0 0.0.0.255 area 0.0.0.0 end
Cek
! perhatikan AS 30 di tambahkan 5x ke routing ke arah AS 10 ! clear ip bgp 10 clear ip bgp 20 show ip bgp show ip route
show ip route show ip bgp 10.100.1000.0/24 show ip bgp neighbors 192.168.2.2 advertised-routes show ip bgp neighbor 192.168.1.1 routes show bgp ipv4 unicast neighbors show bgp ipv4 unicast summary
Referensi
- https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-16/irg-xe-16-book/configuring-a-basic-bgp-network.html
- https://wiki.mikrotik.com/wiki/Manual:Simple_BGP_Multihoming