As was predicted in 1994:
Furthermore, we note that, in all probability, there will be IPv4
hosts on the Internet effectively forever. IPng must provide
mechanisms to allow these hosts to communicate, even after IPng
has become the dominant network layer protocol in the Internet.
It was averted: how do you think we got several billion smartphones connected to the Internet? Do you think that would have been practicable without IPv6?
Comcast—not even mobile—had to move to IPv6 on their landline ISP business because they ran out of IPv4 addresses for TR-069: they were using multiple 10/8 networks in different regions NATed to hide them from each other. IPv4 became untenable.
Put another way, we can drop v6 completely and the Internet will still work. Obviously wouldn't work the other way around.
As for telco addressing handsets, they could use any addressing scheme to be honest. When people talk about averting address exhaustion, they're not talking about internal addressing of networks, different problem altogether.
This is factually difficult to support. (Sent from my iPad which doesn’t have an ipv4 address… to hacker news which has an ipv6 address)
Most people run dual stack and as $favoriteHost gets AAAA, their traffic moves over.
My broader point was that your use of overstatement and a false dichotomy isn't _helping_ us get to a world where IPv6 is dominant.
Only because of NAT. Those cellular CGNATs are v6 on the inside but v4 on the outside (well also v6 but customers need the v4 more).
> At this point it would be best to recognize the sunk cost and give up on the migration. IPv6 will never reach the 100% needed to turn off IPv4.
That was probably a reasonable take 15 years ago. But we're at 50% v6 globally, and the ISPs that are doing v6 + cgnat would not want to move all that v6 traffic to cgnat. v6 traffic is managed with stateless routing; cgnat is stateful and costly.
There are many lessons that can be learned, but v4 only is not the future. v6 only might never happen... people are going to keep running old software in emulation that will never support v6... But global routability of v4 will likely end one day. And I'd suspect the tail of the migration will be much shorter than the head was.
> At this point it would be best to recognize the sunk cost and give up on the migration.
That's a pretty wild thing to say in the comment section of an article about v6 reaching 50% eyeballs-side deployment.
If that’s not a failure I hate to see what is.
How would several billion smartphones be able to connect to the Internet without IPv6?
There isn't enough RFC 1918 (or 100.64.0.0/10) space for IPv4-only to be practical: Comcast—not even mobile—went to IPv6 because running their TR-069 management over multiple 10/8 became untenable.
IPv6 is making all sorts of things possible without most people realizing it.
And how would they have gotten first-hop connectivity without IPv6?
Comcast added IPv6 many years ago on their wired ISP side because they ran out of IPv4 for TR-069 management, and they had way fewer subscribers (at least at the time) than many mobile telcos.
And that half of the Internet is also some of the most bandwidth intensive stuff: Youtube, Netflix, Instagram. The CG-NAT hardware costs of streaming would be huge.
No reason you can’t carry IPv4 over any protocol you want. Multi tennant vxlans can carry whatever you want over your base network. Maybe an IPv6 underlay makes sense there, doesn’t really matter
I think the future is bright and most problems will be solved by 2040, and almost all by 2050.