We need something better than IPv6 that better addresses the needs of users. IPv6 does too much and is too complicated.
Perhaps to someone who's never been exposed to IPv4.
But for those who know IPv4 from before, it means almost a complete rewrite of all the knowledge. Just about every detail of setting up an IPv6 network is different from an IPv4 network, with just the superficial bits staying similar.
It also has bits that are undeniably more complex than IPv4, like dynamic address allocation. You got SLAAC, RA, stateful and stateless DHCPv6, with the latter being required in certain cases. And with that you now got two different ways to provide DNS servers to clients, and which one takes precedence is undeniably non-trivial[1] and even implementation dependent!
[1]: https://datatracker.ietf.org/doc/html/rfc8106#section-5.3.1
Whatever you do to get more addresses, it will look similar in the end, but the steps could've been very different.
How would a router know what to do with it without updating its software?
At the end of the day, you are talking about using a different than IPV4 address scheme and using a different protocol than IPV4. Everything in the stack will need to be updated. Every hop on the route, every single piece of software that will interact with the network address. Backwards compatibility still requires everything but the older device to be updated.
Then once there's sufficient v6 adoption, you can disable v4 entirely and start using /40, /48, etc..
My confusion in the claims that we could do it differently is how the protocol could be updated without actually doing the work of updating everything on the network and adding the new address scheme.
But same addr is the problem we are trying to solve in the first place. Using your IP-new proposal (let's call it IPv5): If every IPv5 addr is just a padded version of the same IPv4 addr, then once IPv4 addresses are exhausted the IPv4-mapped-into-IPv5 addresses are also exhausted.
At that point you need to start handing out IPv5 addresses to hosts without an IPv4 address. And then, how does a IPv5-only host talk to a IPv4-only legacy host? That's the fundamental issue!
The same addr thing only buys you time until the address exhaustion becomes real.
Ipv5 as you call it: Phase 1 is getting routers/hosts to understand v5 headers, while users enable v5 and change nothing else. Phase 2 is the transition where people keep using padded addrs while things* are updated in-place to just support longer ones, which doesn't affect users**. Once that's done, we get to use the full space, which some users may ignore and some may use. For better and worse, the existing /32 blocks would still be around initially. Maybe this would appeal to previous ipv4 holders better; they still own the same % of the pie. Maybe 8.8.8.8 would stay forever.
What makes me kinda sure would've worked? Right now, the world has mostly already completed the equivalent of phases 1 and 2 for ipv6. There might even be a way to reuse the ipv6 protocol as-is for ipv5.
* DNS, NAT, DHCP, ARP, routers, VPSes, OSes...
** "User" includes corp network admins, cloud/datacenter operators, ISPs, and simple home customers.
Edit: I said "my" proposal, but pretty sure the same idea has been brought up many times.
IPv6 also realized that most people don't need their own address space. It is valuable in IPv4 to own an allocation, but IPv6 is so huge it doesn't matter.
For setup, IPv6 does it automatically for customers. Peering requires entering IPv6 addresses, but that is a one time thing.
Basically IPv6 only solves problems if you're paid full time to do network administration.
If you just run a small network among other things, it creates problems. Because you can't hold the new structure in your head if it's not your main job.
> Starting from scratch, IPv6 can make that better.
Yeah right. Want that "things you should never do" Joel link?
He was talking about Netscape, but I think IPv6 is a much better example.
The biggest downside for IPv6 in small networks is, ironically, something which was added later and not part of the initial (nor actually required, but devices opt to do it anyways) and that's "randomized auto rotating addresses" for security. Without them addresses look something like 1234:abcd::${mac} or 1234:abcd::12 but with them they look like 1234:abcd::4729:ab65:f902:7ee0 and a device might have 4 active if it's been running the whole day. I think this one extension is something like 80+% of people's reaction to IPv6 and it didn't even call for it originally.
So yeah, 192.168.1.55 is my Mac's local ip, it's easy to remember.
This address will also run afoul with the "privacy first" randomizations on most devices by default. This addition is truly the scourge of letting IPv6 seem dead simple to use.
IPv6's answer to IPv4 private addresses (e.g. 192.168.0.0/16) is ULA (fd00::/16). Newer routers are beginning to assign local hosts with ULA addresses, thus if you want to have a stable address to a local device, you can simply connect to it by ULA.
Privacy addresses should be used for outgoing connections. Don't treat one as a static address. If you need to write down an address, give that machine an easily remembered static one.
"Let's make a new, backwards incompatible protocol and not learn anything from the old one" doesn't feel like a good idea to me.
IPv6 changed some things, most of them for the better, and it already works. The only problem is migrating and the problem is people who don't want to switch.
One example of how IPv6 is better than IPv4 with more address bits, is that 128-bit address is big enough to put the whole IPv4 address in. NAT64 put the IPv4 address in the 64-bit host section. MAP-T puts the whole NAT state in address, getting rid of expensive CGNAT.
IPv6 supports multiple addresses on each machine for different scopes: global, internal, local. IPv6 uses address hierarchy to figure out which one to use to reach destination.
> It works when you don't have router.
Who doesn't have a router?
Or... Peer to peer links between your router and the ISP?