router bgp 2
 neighbor 10.2.1.2 remote-as 3
 neighbor 10.1.1.1 remote-as 1
 address-family ipv4 unicast
  neighbor 10.2.1.2 activate
  neighbor 10.1.1.1 activate
  network 10.2.0.0 mask 255.255.0.0
  redistribute connected
  aggregate-address 10.2.0.0 255.255.0.0 summary-only
  no auto-summary