alt Hacker News> If they used the old >bolting on top< method by extending ip4 from 4 octets to 8 (or more) octets, then old software could be extended much easier too / probably addresses could be simply mechanically translated too, so ancient software can work.
In every fucking IPv6 thread this "just add more addresses" idea comes up. There is no "just" in expanding the address space:
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Whether you expand the address size to 33, 64 or 128 bits, all IPv4 implementations will discard the packets. So it's a matter of mathematical and physical fact that to expand the address size, you must change the protocol, and that means two things immediately:
1. You have to change the version number.
2. You have to add new code to handle the new version.
Furthermore, you don't want to split the Internet in two, so you must design a method of interworking between the old version and the new version. Annoyingly, you need to do that in a way that can be done completely in machines that know about the new version, because other machines don't know anything at all about the new version, by definition. So,
3. You need a coexistence technique so that updated systems, with the new protocol, can connect to old systems that know nothing of the new protocol.
Two minutes of thought show that this third requirement has only two solutions:
(3A) Dual stack, in which the new machines speak both the old (IPv4) and new (IPng) protocol.
(3B) Translation, in which something translates addresses between the old and new protocols.
This has been known for more than 30 years [RFC1671], although people still sometimes try to deny it.
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* https://github.com/becarpenter/book6/blob/main/01.%20Introdu...
Any IPv4+ idea that "just" adds more address bits will same issues we've faced with IPv6.
Replies
Yes, we want ipv5 that just does 1, 2, 3 instead of ipv6 which does the most complicated variants of those and more. We didn't have requirements 4. change all the pre-existing addresses 5. make addresses randomly assigned 6. make routers accept inbound connections by default 7. give every device its own public IP by default. Ipv6 did those anyway.
Like I own 8.8.8.8. You want to add more bits, fine, I'm 8.8.8.8.0.0.0.0 now. If anyone switches to the new thing, they know where to find me.
The issue the GP is making is that rather than devising a whole new protocol altogether, including resolution and assignments, other things like that, adoption likely would have been much faster and wider.
Had the original plan been simply "extend address space" instead of "extend address space and while we are at it revamp and rewrite every part of the whole scheme including assignment, discovery, and everything else we see wrong with ipv4"; we would be in a much better place.
Adding extra address bytes would of course require new changes across the internet, but that change would be easier to swallow compared to having to rip and replace large swaths of processes to make ipv6 work because of all of the other changes that came with ipv6.
Also, the stupid idea of turning addresses to hex as the default, and more specifically the dumb :: shortening methods really made it confusing for everyone and didnt help at all in the efforts.