5 ms·

It is sort of dissapointing the industry is stubbornly pushing ahead, even after decades, without admitting critical flaw of IPv6 being incompatible with IPv4,

by abpavel 10y ago

It is sort of dissapointing the industry is stubbornly pushing ahead, even after decades, without admitting critical flaw of IPv6 being incompatible with IPv4, and just writing new version. And I'm not talking about the difference such as absence of default gateway concept, replaced by router advertisement. I'm talking about having to build a new parallel Internet, beside the old one, and having to support both networks indefinitely. IPv4 sunset is an illusion. We're stuck with it to the end, and no incompatible protocol will replace it.

adwn 10y ago
Can you expand on why you think that IPv4 will have to be supported across the entire Internet infrastructure for all eternity? Do you think that in 100 years, there will still be devices which support IPv4 exclusively?
- paulddraper 10y ago
  This is software. 100 years is longer than all of existence, let alone eternity.
toast0 10y ago
Wireless carriers in the US (at least) are pushing towards IPv6 only over the air, with their network providing DNS64 and NAT64 (and 464XLAT on devices for IPv4 apps). At this point, it would be reasonable for a mobile device focused on the US market to only support IPv6 over the air; although not if you wanted to use it overseas. There's a clear path for new end-user devices to be IPv6 only, and ISPs to only support a protocol gateway where they interconnect. It's probably a little early for ISPs or devices to start. We're still in the phase where a service can use IPv4 only with little penalty; but there are enough customers with IPv6 enabled, that it may be compelling to use it too.
walshemj 10y ago
Yes it was obvious by say 94/95 that IPV6 was a dog.
deathanatos 10y ago
> critical flaw of IPv6 being incompatible with IPv4 What other choice do we/did we have? I've responded in the past to a different commenter, who lamented IPv6 not being backwards compatible. You can read my response[1] to that comment; essentially, I don't see a way to make IPv6 happen, aside from the introduction of a new, separate network, mostly due to the pigeonhole principle: IPv4 only has 2 ^ 32 addresses, so how do you fit the 2 ^ 128 IPv6 addresses into that scheme? You can introduce a legitimately new protocol, like v6 did. You could perhaps add a special flag, or special block of addresses, or a special option — but whatever mutation you perform on IPv4 packets to "upgrade" them, the intermediate routers would still have to understand that flag in order to properly route packets — no? And thus, since they must understand that flag, you're still upgrading the entire infrastructure, and building out a completely separate network, even if it is just IPv4.1. I do think the IPv4 sunset is far, far out in the future. There will be stragglers for a long time to come, and I'm not sure it's really worth considering when IPv6 isn't deployed to a majority of people yet. But I do think it's possible; at some point, I hope someone realizes that the maintenance of that code is benefiting so few people as to sunset it, perhaps at an ISP-ish level first. No doubt this will break somebody's workflow, though. [1]: https://news.ycombinator.com/item?id=12168656 https://news.ycombinator.com/item?id=12168656
- garaetjjte 10y ago
  Maybe you could add address extension to IPv4 options field. Routers non aware of this would just route packet normally to IPv4 endpoint, at which would reside gateway which looks on extended address field and routes to destination in internal network. That way upgrades would have been needed in server and client network, but intermediate routers could stay IPv4.
  - icebraining 10y ago
    So you'd need to upgrade ISP routers, edge (incl. home) routers, PCs, phones and all IoT devices, along with all their software, but not backbone routers. Would that really have a significant impact? Seems doubtful.
catdog 10y ago
> It is sort of dissapointing the industry is stubbornly pushing ahead, even after decades Then tell us how that magical "compatible" protocol would look like. It's compatible as much as both can coexist and also IP stacks expose a backwards compatible API making it relatively easy for applications to support both. > IPv4 sunset is an illusion. We're stuck with it to the end, and no incompatible protocol will replace it. The ongoing support of the IPv4 is itself not so much a problem, it's there, you don't have to change much if anything. The problem is more of getting v6 support into each and every network device (mostly done now) and overcome the laziness to also configure v6. The "support both" problem is more the other way around, having to also support v4 makes much of the nice features of v6 (e.g. more flexible or in some sense easier configuration) less beneficial so they can not work as a driver to adopt it. I also don't think v4 sunset is an illusion, there will surely be a tipping point somewhere (hard to predict) where some decide v4 is no longer worth the hassle for each and everything pushing the last non-v6 holdouts forward. Sure v4 will not be completely go away anytime soon I think, more of a slow fade out. A big problem nowadays may be that the impact of the IPv4 address exhaustion is distributed unevenly making it really painful for some maintaining v4 connectivity compared to simply activate IPv6 while others can still comfortable ignore it. This may also lead to v6 being deprioritized by those who badly need it because you have to put so much hard work into making v4 work somehow, you can't do without anyway.

by abpavel 10y ago

adwn 10y ago

Can you expand on why you think that IPv4 will have to be supported across the entire Internet infrastructure for all eternity? Do you think that in 100 years, there will still be devices which support IPv4 exclusively?

paulddraper 10y ago
This is software. 100 years is longer than all of existence, let alone eternity.

toast0 10y ago

Wireless carriers in the US (at least) are pushing towards IPv6 only over the air, with their network providing DNS64 and NAT64 (and 464XLAT on devices for IPv4 apps). At this point, it would be reasonable for a mobile device focused on the US market to only support IPv6 over the air; although not if you wanted to use it overseas. There's a clear path for new end-user devices to be IPv6 only, and ISPs to only support a protocol gateway where they interconnect. It's probably a little early for ISPs or devices to start. We're still in the phase where a service can use IPv4 only with little penalty; but there are enough customers with IPv6 enabled, that it may be compelling to use it too.

walshemj 10y ago

Yes it was obvious by say 94/95 that IPV6 was a dog.

deathanatos 10y ago

> critical flaw of IPv6 being incompatible with IPv4 What other choice do we/did we have? I've responded in the past to a different commenter, who lamented IPv6 not being backwards compatible. You can read my response[1] to that comment; essentially, I don't see a way to make IPv6 happen, aside from the introduction of a new, separate network, mostly due to the pigeonhole principle: IPv4 only has 2 ^ 32 addresses, so how do you fit the 2 ^ 128 IPv6 addresses into that scheme? You can introduce a legitimately new protocol, like v6 did. You could perhaps add a special flag, or special block of addresses, or a special option — but whatever mutation you perform on IPv4 packets to "upgrade" them, the intermediate routers would still have to understand that flag in order to properly route packets — no? And thus, since they must understand that flag, you're still upgrading the entire infrastructure, and building out a completely separate network, even if it is just IPv4.1. I do think the IPv4 sunset is far, far out in the future. There will be stragglers for a long time to come, and I'm not sure it's really worth considering when IPv6 isn't deployed to a majority of people yet. But I do think it's possible; at some point, I hope someone realizes that the maintenance of that code is benefiting so few people as to sunset it, perhaps at an ISP-ish level first. No doubt this will break somebody's workflow, though. [1]: https://news.ycombinator.com/item?id=12168656 https://news.ycombinator.com/item?id=12168656

garaetjjte 10y ago
Maybe you could add address extension to IPv4 options field. Routers non aware of this would just route packet normally to IPv4 endpoint, at which would reside gateway which looks on extended address field and routes to destination in internal network. That way upgrades would have been needed in server and client network, but intermediate routers could stay IPv4.
- icebraining 10y ago
  So you'd need to upgrade ISP routers, edge (incl. home) routers, PCs, phones and all IoT devices, along with all their software, but not backbone routers. Would that really have a significant impact? Seems doubtful.

catdog 10y ago

> It is sort of dissapointing the industry is stubbornly pushing ahead, even after decades Then tell us how that magical "compatible" protocol would look like. It's compatible as much as both can coexist and also IP stacks expose a backwards compatible API making it relatively easy for applications to support both. > IPv4 sunset is an illusion. We're stuck with it to the end, and no incompatible protocol will replace it. The ongoing support of the IPv4 is itself not so much a problem, it's there, you don't have to change much if anything. The problem is more of getting v6 support into each and every network device (mostly done now) and overcome the laziness to also configure v6. The "support both" problem is more the other way around, having to also support v4 makes much of the nice features of v6 (e.g. more flexible or in some sense easier configuration) less beneficial so they can not work as a driver to adopt it. I also don't think v4 sunset is an illusion, there will surely be a tipping point somewhere (hard to predict) where some decide v4 is no longer worth the hassle for each and everything pushing the last non-v6 holdouts forward. Sure v4 will not be completely go away anytime soon I think, more of a slow fade out. A big problem nowadays may be that the impact of the IPv4 address exhaustion is distributed unevenly making it really painful for some maintaining v4 connectivity compared to simply activate IPv6 while others can still comfortable ignore it. This may also lead to v6 being deprioritized by those who badly need it because you have to put so much hard work into making v4 work somehow, you can't do without anyway.