IPv4.5

Problem: 1) We're quickly running out of IPv4 addresses 2) Poor nations cannot afford many IPv4 addresses 3) ISPs are delaying implementing IPv6 because of capital cost

Intermediate solution: 1) There's nothing wrong with IPv6, we should all be using it today. 2) We use IPv4 mostly for the internet, using only a single TCP port, port 80. So we're wasting the full potential of 65536 ports available. 3) Instead of giving everyone their own IP, have an ISP account page so you can set up port forwarding (instead of doing so on your internet router). 4) Now we effectively have 6 tuples in an IPv4 address - giving us another 65K times the amount of addresses - enough to get by...

More detail: Of course we still need ports to poke out to the internet. So an ISP would have one IP for all servers and then a small pool of IPs for NATing out. Depending on the size of the ISP the pool would be much smaller than a regular subnet.

So for an ISP with 10,000 customers. Half with port forwarding for web servers or P2P applications and the like you would only need 1 IP to service the 5,000 odd server ports. Contention for an outbound port assumed at 6:1 (especially when you have multiple browser tabs open with AJAX) - you still only need 1 IP to service 10,000 customers! So instead of 10,000 IPs you only need to use 2.