A Better Approach than Carrier-Grade-NAT
Olaf Maennel, Randy Bush, Luca Cittadini, Steven M. Bellovin · 2008
We are facing the exhaustion of newly assignable IPv4 addresses. 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 addresses. Letting hosts seamlessly communicate in an IPv4-world without assigning a unique globally routable IPv4 address to each of them is a challenging problem, for which many solutions have been proposed. Some prominent ones target towards carrier-grade-NATs (CGN), which we feel is a bad idea. Instead, we propose using specialized NATs at the edge that treat some of the port number bits as part of the address.