Configuration for AS1 EBGP1
The following is the configuration used for Exterior Border Gateway Protocol router 1 (EBGP1). EBGP1 is configured with the redistribute connected subnets command and interfaces with AS2.
ip cef
interface LoopbackO ip address 10.0.0.4 255.255.255.255
interface Ethernet0/0 description EBGP1 to P1 ip address 10.2.1.2 255.255.255.0 tag-switching ip
interface Serial0/0 description EBGP1 to EBGP2 ip address 12.0.0.1 255.255.255.252
router ospf 1 log-adjacency-changes redistribute connected subnets network 10.0.0.0 0.255.255.255 area 0
router bgp 1 no synchronization no bgp default route-target filter bgp log-neighbor-changes neighbor R peer-group neighbor R remote-as 1
neighbor R update-source Loopback0
neighbor 12.0.0.2 remote-as 2
neighbor 10.0.0.2 peer-group R
address-family vpnv4
neighbor R activate neighbor R send-community extended neighbor 12.0.0.2 activate neighbor 12.0.0.2 send-community extended neighbor 10.0.0.2 peer-group R no auto-summary exit-address-family
The following is the configuration used for Exterior Border Gateway Protocol router 2 (EBGP2). EBGP2 is configured with the neighbor next-hop-self command and interfaces with AS1.
ip cef
ip vrf VPN1 rd 2:103
route-target export 1:100 route-target import 1:100
interface Loopback0 ip address 20.0.0.3 255.255.255.255 ip router isis
interface Loopbackl ip vrf forwarding VPNl ip address 172.16.0.3 255.255.255.255
interface Serial0/0 description EBGP2 to P2 ip unnumbered Loopback0 ip router isis tag-switching ip
interface Serial0/1 description EBGP2 to EBGP1 ip address 12.0.0.2 255.255.255.252
router isis net 49.0002.0000.0000.0003.00
router bgp 2 no synchronization no bgp default route-target filter bgp log-neighbor-changes neighbor 12.0.0.1 remote-as 1
neighbor 20.0.0.8 remote-as 2
neighbor 20.0.0.8 update-source Loopback0
neighbor 20.0.0.8 next-hop-self
address-family ipv4 vrf Vl redistribute connected no auto-summary no synchronization exit-address-family
address-family vpnv4 neighbor 12.0.0.1 activate neighbor 12.0.0.1 send-community extended neighbor 20.0.0.8 activate neighbor 20.0.0.8 next-hop-self neighbor 20.0.0.8 send-community extended exit-address-family
The following is the configuration used for the provider (P) router P2. P2 acts as a route reflector for all IBGP devices within AS2.
ip vrf VPN1 rd 2:108
route-target export 1:100 route-target import 1:100
interface Loopback0 ip address 20.0.0.8 255.255.255.255 ip router isis
interface Loopback1 ip vrf forwarding VPN1 ip address 172.16.0.8 255.255.255.255
interface Ethernet0/0 description P2 to PE2 ip address 20.9.1.2 255.255.255.0 ip router isis tag-switching ip
interface Serial0/0 description P2 to EBGP2 ip unnumbered Loopback0 ip router isis tag-switching ip
router isis net 49.0002.0000.0000.0008.00
router bgp 2
no synchronization bgp log-neighbor-changes neighbor R peer-group neighbor R remote-as 2
neighbor R update-source Loopback0
neighbor R route-reflector-client neighbor 20.0.0.3 peer-group R
address-family ipv4 vrf VPN1 redistribute connected no auto-summary no synchronization exit-address-family
address-family vpnv4 neighbor R activate neighbor R route-reflector-client neighbor R send-community extended neighbor 20.0.0.3 peer-group R neighbor 20.0.0.9 peer-group R exit-address-family
Continue reading here: Figure 513 Backbone Carrier Supporting an ISP
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