Lee Howard wrote:
MAP-T, MAP-E. IPv6-only between CE and Border Relay (BR). CPE is provisioned with an IPv4 address and a range of ports. It does basic NAT44, but only uses the reserved ports. Then it translates to IPv6 (MAP-T) or encapsulates in IPv6 (MAP-E) and forwards to the configured Border Relay (BR), which changes it to IPv4. Pro: Stateless, very efficient. Con: Very little CPE support in home routers.
So, all we need is NAT44 CPE, which only uses a reserved block of ports, which is (semi) statically configured by ISP operated gateway. Pro: Stateless, very efficient, no IPv6 necessary Con: No current CPE support. As for protocol, assuming port mapping on UPnP gateway is statically configured by ISPs not changable from CPE side, GetListOfPortMappings() of UPnP should be useful for CPEs to know range of ports to be used by them. Masataka Ohta