3 ms·

Why didn't we expand IPv4 to take 64 or 128-bit addresses and instead created IPv6?

lmm 11y ago
Did you read the article? Every router... routes, so every router needs to speak the new protocol. If you tried to send packets in an IPv4-compatible way, what would you put for their addresses? They'd end up in nondeterministic routing loops which would be terrible to debug.
- protomyth 11y ago
  I'm asking why did the create IPv6 instead of a version of IPv4 with an expanded address (IPv4-version 2)? Why did they not do an incremental change instead of a whole new thing?
  - teraflop 11y ago
    It's a distinction without a difference. Any protocol with addresses larger than 32 bits will necessarily be incompatible with IPv4, so what does it matter whether there's a "4" or a "6" in the name?
    - protomyth 11y ago
      IPv6 seems to be a whole lot more complicated than just upping the number of bits used for addresses. Its like they were trying to solve a bunch of things in addition to the address range.
      - lmm 11y ago
        Per the article it mostly has the same headers. What other things are you thinking of? Stateless autoconfig is complex but IPv4 has that option too. Privacy extensions are complex but they are extensions, not the core spec.
        deleted 11y ago
        [deleted]
        protomyth 11y ago
        see my response to XorNot - there are differences
        chemodax 11y ago
        IPv6 introduced several significant changes like dropping IP packet fragmentation.
  - XorNot 11y ago
    Develop the nanotech necessary for us to do upgrades of ASIC chips in routers, and ... it still wouldn't make a difference. You can't negotiate with etched silicon.
    - protomyth 11y ago
      Those devices aren't going to IPv6 either. I'm wondering what was the idea behind not just expanding the address space.
      - XorNot 11y ago
        We did just expand the address space, is my point. The entire IPv4 range is mapped into IPv6 on a prefix - which is what you're suggesting. IPv4 can be represented in IPv6 as ::ffff:192.0.2.128 for example. My whole point is that its irrelevant what we did or didn't do, because hardware routers are not software reconfigurable. Whether you expand the address space a little or a lot is irrelevant, because it will cost exactly the same to replace that hardware - in which case, if you have to expand the address space you should expand it by the most you possibly can in order to ensure you don't ever have to replace those routers again.
        protomyth 11y ago
        It isn't just the same. https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6-differences.pdf https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6... https://en.wikipedia.org/wiki/IPv6 https://en.wikipedia.org/wiki/IPv6 The justification of why NAT is no longer necessary is nice in a theoretical sense but a pain in the butt if I'm trying to convert my network. The mapping of IPv4 to IPv6 occurred in 2006 with https://tools.ietf.org/html/rfc4291 https://tools.ietf.org/html/rfc4291
        lmm 11y ago
        > It isn't just the same. https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6.. https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6.... https://en.wikipedia.org/wiki/IPv6 https://en.wikipedia.org/wiki/IPv6 You can't just link to a long article and claim it shows things are different. What specific differences are you bothered about? > The justification of why NAT is no longer necessary is nice in a theoretical sense but a pain in the butt if I'm trying to convert my network. Having used IPv4 networks that used all publicly routeable addresses and ones that did not, the former have always been much nicer, even at a purely practical level of "I want to connect to my work VPN and have it work".

lmm 11y ago

Did you read the article? Every router... routes, so every router needs to speak the new protocol. If you tried to send packets in an IPv4-compatible way, what would you put for their addresses? They'd end up in nondeterministic routing loops which would be terrible to debug.

protomyth 11y ago
I'm asking why did the create IPv6 instead of a version of IPv4 with an expanded address (IPv4-version 2)? Why did they not do an incremental change instead of a whole new thing?
- teraflop 11y ago
  It's a distinction without a difference. Any protocol with addresses larger than 32 bits will necessarily be incompatible with IPv4, so what does it matter whether there's a "4" or a "6" in the name?
  - protomyth 11y ago
    IPv6 seems to be a whole lot more complicated than just upping the number of bits used for addresses. Its like they were trying to solve a bunch of things in addition to the address range.
    - lmm 11y ago
      Per the article it mostly has the same headers. What other things are you thinking of? Stateless autoconfig is complex but IPv4 has that option too. Privacy extensions are complex but they are extensions, not the core spec.
      - deleted 11y ago
        [deleted]
      - protomyth 11y ago
        see my response to XorNot - there are differences
      - chemodax 11y ago
        IPv6 introduced several significant changes like dropping IP packet fragmentation.
- XorNot 11y ago
  Develop the nanotech necessary for us to do upgrades of ASIC chips in routers, and ... it still wouldn't make a difference. You can't negotiate with etched silicon.
  - protomyth 11y ago
    Those devices aren't going to IPv6 either. I'm wondering what was the idea behind not just expanding the address space.
    - XorNot 11y ago
      We did just expand the address space, is my point. The entire IPv4 range is mapped into IPv6 on a prefix - which is what you're suggesting. IPv4 can be represented in IPv6 as ::ffff:192.0.2.128 for example. My whole point is that its irrelevant what we did or didn't do, because hardware routers are not software reconfigurable. Whether you expand the address space a little or a lot is irrelevant, because it will cost exactly the same to replace that hardware - in which case, if you have to expand the address space you should expand it by the most you possibly can in order to ensure you don't ever have to replace those routers again.
      - protomyth 11y ago
        It isn't just the same. https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6-differences.pdf https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6... https://en.wikipedia.org/wiki/IPv6 https://en.wikipedia.org/wiki/IPv6 The justification of why NAT is no longer necessary is nice in a theoretical sense but a pain in the butt if I'm trying to convert my network. The mapping of IPv4 to IPv6 occurred in 2006 with https://tools.ietf.org/html/rfc4291 https://tools.ietf.org/html/rfc4291
        lmm 11y ago
        > It isn't just the same. https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6.. https://www.juniper.net/techpubs/en_US/learn-about/ipv4-ipv6.... https://en.wikipedia.org/wiki/IPv6 https://en.wikipedia.org/wiki/IPv6 You can't just link to a long article and claim it shows things are different. What specific differences are you bothered about? > The justification of why NAT is no longer necessary is nice in a theoretical sense but a pain in the butt if I'm trying to convert my network. Having used IPv4 networks that used all publicly routeable addresses and ones that did not, the former have always been much nicer, even at a purely practical level of "I want to connect to my work VPN and have it work".