4 ms·

The point of IPv4x and similar proposals is to avoid a dual-stack scenario by reducing the risk of switching. Going from v4 to v4x doesn't mean changing all you

The point of IPv4x and similar proposals is to avoid a dual-stack scenario by reducing the risk of switching. Going from v4 to v4x doesn't mean changing all your routes and addresses (and possibly blacklists), you just enable it and everything still works. Network components can get updated/replaced with the longer addr field behind the scenes without user impact, then once the world is ready, ISPs can finally start using the extra address space.

Dagger2 7mo ago
But like the similar proposals, it fails to avoid a dual-stack scenario. Note that going from v4 to v6 also doesn't mean changing all your routes and addresses; you just enable it and everything still works. Network components can get updated behind the scenes without user impact. There's no flag day though; ISPs can start using the new address space as soon as they want, rather than being forced to wait until everybody else is ready.
- zadikian 7mo ago
  You do have to change everything to actually use v6 rather than having v4 on the side. Re: flag day, I guess you could use the new address space of v4x before everyone is ready, provided the other side supports it.
  - throw0101d 7mo ago
    Having partial deployment of IPv4x is no different than having partial deployment of IPv6: you have islands of it and have to fall back to the 'legacy' IPv4-plain protocol when the new protocol fails to connect: * https://en.wikipedia.org/wiki/Happy_Eyeballs https://en.wikipedia.org/wiki/Happy_Eyeballs Getting "free" new-protocol addresses is also nothing new: > For any 32-bit global IPv4 address that is assigned to a host, a 48-bit 6to4 IPv6 prefix can be constructed for use by that host (and if applicable the network behind it) by appending the IPv4 address to 2002::/16. > For example, the global IPv4 address 192.0.2.4 has the corresponding 6to4 prefix 2002:c000:0204::/48. This gives a prefix length of 48 bits, which leaves room for a 16-bit subnet field and 64 bit host addresses within the subnets. * https://en.wikipedia.org/wiki/6to4 https://en.wikipedia.org/wiki/6to4 Translation boxes and tunnels are still needed for both IPv4x and IPv6.
    - zadikian 7mo ago
      Ok, I see what you mean then by 6to4 already supporting what v4x proposed, but that path wasn't taken either. It's a special feature with rare usage rather than the minimum default way of doing v6.
      - Dagger2 7mo ago
        We did take that path. If you zoom in on the start of https://www.google.co.uk/intl/en/ipv6/statistics.html https://www.google.co.uk/intl/en/ipv6/statistics.html you can see that 6to4+Teredo was more common than native until 2010. (Okay, that's combined with Teredo, but I think probably 6to4 is the majority of it because Windows will use 6to4 without needing a registry change or custom application behavior.) You see it as a special feature with rare usage because it competed with native and lost. People overwhelmingly preferred deploying v6 natively instead of deploying 6to4. Obviously more people would be using it if it was the only option, but if you're trying to come up with an alternative to the way v6 went then "an approach that v6 took but which nobody wanted to use when native v6 was the alternative" might not be a very promising place to start.
        zadikian 7mo ago
        It's not like the v6 spec said, here are two options on equal footing, go figure out which is better. 6to4 was a temp bolt-on. I had to look up what things were actually like in 2010 because I really don't remember getting a 2002:, which brought me to rfc6343 that explained why exactly 6to4 suffered. A big part of it is that even a v6-enabled ISP didn't give you a 2002:, rather you were relying on anycast to reach a relay server. Why would an ISP or user ever want that mess? Either they do v6, or more likely they don't care and focus on v4. So actually I take it back, 6to4 was pretty different from this ipv4x idea. I misunderstood and thought a v6-enabled ISP would give you a 2002: under 6to4, which you could later subdivide. Ignoring that, say 6to4 were like v4x... The idea that those 2 years showed that native was preferable, that was among a small minority who even cared about v6 to begin with (0.25% at the time). This was a primary, not a final.
        7mo ago
  - Dagger2 7mo ago
    If your goal is just to roll out support for v6 addresses without actually using them, then you don't need to change anything about your network to do that. (Remember going from XP to Vista? That added support for v6 in Windows, but you didn't need to change your network for it.) This is the same as your described rollout of support for v4x. Once the world is ready and your ISP actually issues you with v6, then you need to change some things (I would argue not everything). Again, this is the same as for v4x. The only difference is that in the v4x case, you put this after the end and ignored it. Ignoring the bit you don't like for one of them but not for the other isn't a fair comparison.
    - zadikian 7mo ago
      Yeah I'm with you on not needing to change much to have v6 without actually using it. But when the world is actually ready for v6, you do need to change everything. And it's worse than that, the world only becomes ready by people changing everything before the world is ready. You said I put this part at the end of v4x, and yes that's the point, the ordering of changes matters.
      - Dagger2 7mo ago
        So your suggested ordering is for everybody to add support for your v4x addresses in every OS, device, software, API, protocol etc, and then only allow them to make use of the extra address space after everybody else has also added support everywhere? To be clear, you don't need to change much in order to have v4x without using the extra address space... but starting to use that extra space means changing everything in the same sense that starting to use the extra address space from v6 means changing everything. At least with v6 you don't have to wait for the rest of the world to be ready. You can start using it straight away. What you're asking for would give people _less_ motivation to do the work, so the "the world only becomes ready" problem gets worse. How is this better?
        zadikian 7mo ago
        To answer your first question, if both hosts understand v4x, you can still use the extra space before everyone else is using it. v6 has the same limitation except all routers in between also need to understand it, unless you've set up 6to4 which is more configuration. But this isn't even the main issue. How is v4x easier, because from many parties' perspectives (end users, ISPs, hosts), there is little to no change. Yes, whoever makes the router or OS has to deal with the new protocol. Now if you buy a new router or update your OS, it supports and truly uses v4x without you needing to configure anything. Unlike v6 where even if you don't make a router or OS, you very much have to deal with it as a sysadmin or maybe even an end user. How is v4x more motivating, well to most people it's not. It's just easier. Those who already own large v4 blocks might be more motivated to support v4x than v6, but it's a double-edged sword. I'm not saying it's simply better though. There are downsides. It's better if your only goal is to extend the address space.

Dagger2 7mo ago

But like the similar proposals, it fails to avoid a dual-stack scenario. Note that going from v4 to v6 also doesn't mean changing all your routes and addresses; you just enable it and everything still works. Network components can get updated behind the scenes without user impact. There's no flag day though; ISPs can start using the new address space as soon as they want, rather than being forced to wait until everybody else is ready.

zadikian 7mo ago
You do have to change everything to actually use v6 rather than having v4 on the side. Re: flag day, I guess you could use the new address space of v4x before everyone is ready, provided the other side supports it.
- throw0101d 7mo ago
  Having partial deployment of IPv4x is no different than having partial deployment of IPv6: you have islands of it and have to fall back to the 'legacy' IPv4-plain protocol when the new protocol fails to connect: * https://en.wikipedia.org/wiki/Happy_Eyeballs https://en.wikipedia.org/wiki/Happy_Eyeballs Getting "free" new-protocol addresses is also nothing new: > For any 32-bit global IPv4 address that is assigned to a host, a 48-bit 6to4 IPv6 prefix can be constructed for use by that host (and if applicable the network behind it) by appending the IPv4 address to 2002::/16. > For example, the global IPv4 address 192.0.2.4 has the corresponding 6to4 prefix 2002:c000:0204::/48. This gives a prefix length of 48 bits, which leaves room for a 16-bit subnet field and 64 bit host addresses within the subnets. * https://en.wikipedia.org/wiki/6to4 https://en.wikipedia.org/wiki/6to4 Translation boxes and tunnels are still needed for both IPv4x and IPv6.
  - zadikian 7mo ago
    Ok, I see what you mean then by 6to4 already supporting what v4x proposed, but that path wasn't taken either. It's a special feature with rare usage rather than the minimum default way of doing v6.
    - Dagger2 7mo ago
      We did take that path. If you zoom in on the start of https://www.google.co.uk/intl/en/ipv6/statistics.html https://www.google.co.uk/intl/en/ipv6/statistics.html you can see that 6to4+Teredo was more common than native until 2010. (Okay, that's combined with Teredo, but I think probably 6to4 is the majority of it because Windows will use 6to4 without needing a registry change or custom application behavior.) You see it as a special feature with rare usage because it competed with native and lost. People overwhelmingly preferred deploying v6 natively instead of deploying 6to4. Obviously more people would be using it if it was the only option, but if you're trying to come up with an alternative to the way v6 went then "an approach that v6 took but which nobody wanted to use when native v6 was the alternative" might not be a very promising place to start.
      - zadikian 7mo ago
        It's not like the v6 spec said, here are two options on equal footing, go figure out which is better. 6to4 was a temp bolt-on. I had to look up what things were actually like in 2010 because I really don't remember getting a 2002:, which brought me to rfc6343 that explained why exactly 6to4 suffered. A big part of it is that even a v6-enabled ISP didn't give you a 2002:, rather you were relying on anycast to reach a relay server. Why would an ISP or user ever want that mess? Either they do v6, or more likely they don't care and focus on v4. So actually I take it back, 6to4 was pretty different from this ipv4x idea. I misunderstood and thought a v6-enabled ISP would give you a 2002: under 6to4, which you could later subdivide. Ignoring that, say 6to4 were like v4x... The idea that those 2 years showed that native was preferable, that was among a small minority who even cared about v6 to begin with (0.25% at the time). This was a primary, not a final.
        7mo ago
- Dagger2 7mo ago
  If your goal is just to roll out support for v6 addresses without actually using them, then you don't need to change anything about your network to do that. (Remember going from XP to Vista? That added support for v6 in Windows, but you didn't need to change your network for it.) This is the same as your described rollout of support for v4x. Once the world is ready and your ISP actually issues you with v6, then you need to change some things (I would argue not everything). Again, this is the same as for v4x. The only difference is that in the v4x case, you put this after the end and ignored it. Ignoring the bit you don't like for one of them but not for the other isn't a fair comparison.
  - zadikian 7mo ago
    Yeah I'm with you on not needing to change much to have v6 without actually using it. But when the world is actually ready for v6, you do need to change everything. And it's worse than that, the world only becomes ready by people changing everything before the world is ready. You said I put this part at the end of v4x, and yes that's the point, the ordering of changes matters.
    - Dagger2 7mo ago
      So your suggested ordering is for everybody to add support for your v4x addresses in every OS, device, software, API, protocol etc, and then only allow them to make use of the extra address space after everybody else has also added support everywhere? To be clear, you don't need to change much in order to have v4x without using the extra address space... but starting to use that extra space means changing everything in the same sense that starting to use the extra address space from v6 means changing everything. At least with v6 you don't have to wait for the rest of the world to be ready. You can start using it straight away. What you're asking for would give people _less_ motivation to do the work, so the "the world only becomes ready" problem gets worse. How is this better?
      - zadikian 7mo ago
        To answer your first question, if both hosts understand v4x, you can still use the extra space before everyone else is using it. v6 has the same limitation except all routers in between also need to understand it, unless you've set up 6to4 which is more configuration. But this isn't even the main issue. How is v4x easier, because from many parties' perspectives (end users, ISPs, hosts), there is little to no change. Yes, whoever makes the router or OS has to deal with the new protocol. Now if you buy a new router or update your OS, it supports and truly uses v4x without you needing to configure anything. Unlike v6 where even if you don't make a router or OS, you very much have to deal with it as a sysadmin or maybe even an end user. How is v4x more motivating, well to most people it's not. It's just easier. Those who already own large v4 blocks might be more motivated to support v4x than v6, but it's a double-edged sword. I'm not saying it's simply better though. There are downsides. It's better if your only goal is to extend the address space.