+-------------+             +----------+
        Private |    lwB4     | IPv4-in-IPv6| Stateless|
+------+  IPv4  |------+------|    Tunnel   |  lwAFTR  |     _______
| IPv4 |------->|      |Encap.|------------>|(encap/A+P|    ( IPv4  )
|Device|<-------| NAPT |  /   |<------------|bind. tab +--( Internet )
+------+        |  44  |Decap.|      ^      | routing) |   (________)
                +------+------+      |      +----------+
                              Operator IPv6
                                  Network