ggsn ggsn0
 apn internet
  gtpu-mode tun
  tun-device tun4
  type-support v4
  ip prefix dynamic 176.16.16.0/20
  ip dns 0 172.18.3.201
  ip dns 1 8.8.8.8
  ip ifconfig 176.16.16.0/20
  no shutdown
 default-apn internet
 no shutdown ggsn
