upper        lower
  +--=----[ em4: ]----------+
  |                         |
  | iface1           iface2 |
  +-------[         ]-------+
   out1   [ netflow ] out2
  +-------[         ]-------+
  |                         |
  +-------------------------+


       mkpeer em4: netflow lower iface0
       name em4:lower netflow
       connect em4: netflow: upper iface1
       connect netflow: netflow: out0 out1
       mkpeer netflow: ksocket export inet/dgram/udp
       msg netflow:export bind  inet/10.10.0.1:3510
       msg netflow:export connect inet/10.20.30.40:3510