frr defaults traditional
hostname r1
interface eth1
 ip address 10.213.100.1/30
interface eth2
 ip address 10.213.11.1/24
interface eth3
 ip address 10.213.21.1/24
interface eth4
 ip address 10.213.30.1/24
! Aquí no interesan las políticas, sino qué camino gana: basta con el AS path más corto.
router bgp 65301
 bgp router-id 10.213.100.1
 no bgp ebgp-requires-policy
 timers bgp 1 3
 neighbor 10.213.100.2 remote-as 65302
 neighbor 10.213.100.2 advertisement-interval 0
 neighbor 10.213.21.10 remote-as 65310
 neighbor 10.213.21.10 advertisement-interval 0
 address-family ipv4 unicast
  network 10.213.11.0/24
  network 10.213.21.0/24
  network 10.213.30.0/24