Comment by tracker1
4 days ago
I'm largely with you... I would think they'd take the IPv4 block and have a direct/virtual block that just extends it to more addresses... so it could be an IPv4 NAT or IPv6 direct.
like 1.1.1.1/192.168.45.4 ... for a router that understands IPv6, that's the direct route to the sub-network, otherwise it will have to use IPv4, and the subnet route is treated as NAT and otherwise isolated.
To me, that would make more sense... then internal IPv6 might be practically limited to 10. and 102.168. in the nearer term, but adoption would be MUCH simpler in practice, and distribution would mostly already be established, however unfairly, but can then be broken into single addresses and vNext adoption could be that much quicker as a result of piggybacking.
AFAIK this was one of several things that was tried, but failed for various reasons. It's called "TUBA" - TCP/UDP with Bigger Addresses - adding extra address bits at a layer above IP so that IP remains compatible.
I think one of the main problems with it is that you have to update the whole internet anyway, just like you do with IPv6, so you make the protocol stack stupider for no real benefit.
An alternate to IPv6 would have been to store the NAT addresses in IPv4 somehwere. But the IPv4 options are fragile and normal NAT would likely destroy them. It would still require rewriting all of the networking and software. It would have engrained NAT everywhere and made lots of routing problems, like is that your or mine 10. network.
>limited to 10. and 102.168
I assume you meant 10.x.x.x and 192.168.x.x -- (and 172.16.x.x?), ie the standard subnets for home router-modems (which are non-routing and so can't be used on the internet).