Create external network, and its associated subnet:
# Source the admin tenant credentials $ . keystonerc_admin $ keystone tenant-list | grep services | awk '{print $2;}' 3e112abc4c4b4214b8efbd627a32f75e $ neutron net-create --tenant-id 3e112abc4c4b4214b8efbd627a32f75e \ ext --router:external=True