A Better Approach than Carrier-Grade-NAT

We are facing the exhaustion of newly assignable IPv4 ad-dresses. Unfortunately, IPv6 is not yet deployed widely enough to fully replace IPv4, and it is unrealistic to expect that this is going to change before we run out of IPv4 ad-dresses. Letting hosts seamlessly communicate in an IPv4-world without assigning a unique globally routable IPv4 ad-dress to each of them is a challenging problem, for which many solutions have been proposed. Some prominent ones target towards carrier-grade-NATs (CGN), e.g. [1], which we feel is a bad idea. Instead, we propose using specialized NATs that treat some of the port number bits as part of the address. 1