=== R1 ===
hostname R1
ip cef
interface Loopback0
 ip address 10.255.0.1 255.255.255.255
exit
interface GigabitEthernet1
 ip address 192.0.2.1 255.255.255.252
 no shutdown
exit
interface GigabitEthernet2
 ip address 192.0.2.5 255.255.255.252
 no shutdown
exit
router bgp 65001
 bgp router-id 10.255.0.1
 no bgp default ipv4-unicast
 neighbor 192.0.2.2 remote-as 65023
 neighbor 192.0.2.6 remote-as 65023
 address-family ipv4 unicast
  no auto-summary
  neighbor 192.0.2.2 activate
  neighbor 192.0.2.6 activate
 exit-address-family
end

=== R2 ===
hostname R2
ip cef
interface Loopback0
 ip address 10.255.0.2 255.255.255.255
exit
interface Loopback10
 ip address 198.51.100.1 255.255.255.0
exit
interface GigabitEthernet1
 ip address 192.0.2.2 255.255.255.252
 no shutdown
exit
interface GigabitEthernet2
 ip address 192.0.2.9 255.255.255.252
 no shutdown
exit
router bgp 65023
 bgp router-id 10.255.0.2
 no bgp default ipv4-unicast
 neighbor 192.0.2.1 remote-as 65001
 neighbor 192.0.2.10 remote-as 65023
 address-family ipv4 unicast
  no auto-summary
  neighbor 192.0.2.1 activate
  neighbor 192.0.2.10 activate
  network 198.51.100.0 mask 255.255.255.0
 exit-address-family
end

=== R3 ===
hostname R3
ip cef
interface Loopback0
 ip address 10.255.0.3 255.255.255.255
exit
interface Loopback10
 ip address 198.51.100.1 255.255.255.0
exit
interface GigabitEthernet1
 ip address 192.0.2.6 255.255.255.252
 no shutdown
exit
interface GigabitEthernet2
 ip address 192.0.2.10 255.255.255.252
 no shutdown
exit
router bgp 65023
 bgp router-id 10.255.0.3
 no bgp default ipv4-unicast
 neighbor 192.0.2.5 remote-as 65001
 neighbor 192.0.2.9 remote-as 65023
 address-family ipv4 unicast
  no auto-summary
  neighbor 192.0.2.5 activate
  neighbor 192.0.2.9 activate
  network 198.51.100.0 mask 255.255.255.0
 exit-address-family
end