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UTF8 is backward compatible with ASCII just fine - latter is a strict subset of former. It doesn't get more backward-compatible than that! IPv6, on the other h

by aexaey 9y ago

UTF8 is backward compatible with ASCII just fine - latter is a strict subset of former. It doesn't get more backward-compatible than that! IPv6, on the other hand, is not at all backward compatible with IPv4 (was never a design goal - magic of OSI stack was supposed to do it's thing). One would argue that incompatibility is in large part responsible for the 6's slow start - even though afterthought bolt-ons eventually did see sunlight - ::ffff:x.x.x.x thing, cornucopia of tunnels and dual-stacks of various degree lite-ness, etc.

zAy0LfpBZLC8mAC 9y ago
... which means that if of two parties only one understand UTF-8, they have to speak ASCII. ASCII being a subset of UTF-8 does not provide and benefit in that regard, just as IPv4 addresses being a subset of IPv6 addresses wouldn't.
- aexaey 9y ago
  Let me drill down it for you: Imagine two endpoints talking a backward compatible pair of standards: A only speaks ASCII, B only speaks UTF-8. Would you think they will be able to communicate at least something? Now imagine two endpoints talking a not backward compatible pair: A only speaks IPv4, and B only speaks IPv6. Will they be able to communicate, at least something? See the difference?
  - zAy0LfpBZLC8mAC 9y ago
    > Imagine two endpoints talking a backward compatible pair of standards: A only speaks ASCII, B only speaks UTF-8. Would you think they will be able to communicate at least something? As long as they only speak ASCII, yes. > Now imagine two endpoints talking a not backward compatible pair: A only speaks IPv4, and B only speaks IPv6. Will they be able to communicate, at least something? That's why you deploy IPv6 dual-stacked with IPv4. That way, if two parties only speak IPv4, it's completely backwards compatible. > See the difference? Sure do I see the difference. What I don't see is how to apply any of that to the v4 to v6 transition in a way that would have any advantage over how it is being done now.

by aexaey 9y ago

zAy0LfpBZLC8mAC 9y ago

... which means that if of two parties only one understand UTF-8, they have to speak ASCII. ASCII being a subset of UTF-8 does not provide and benefit in that regard, just as IPv4 addresses being a subset of IPv6 addresses wouldn't.

aexaey 9y ago
Let me drill down it for you: Imagine two endpoints talking a backward compatible pair of standards: A only speaks ASCII, B only speaks UTF-8. Would you think they will be able to communicate at least something? Now imagine two endpoints talking a not backward compatible pair: A only speaks IPv4, and B only speaks IPv6. Will they be able to communicate, at least something? See the difference?
- zAy0LfpBZLC8mAC 9y ago
  > Imagine two endpoints talking a backward compatible pair of standards: A only speaks ASCII, B only speaks UTF-8. Would you think they will be able to communicate at least something? As long as they only speak ASCII, yes. > Now imagine two endpoints talking a not backward compatible pair: A only speaks IPv4, and B only speaks IPv6. Will they be able to communicate, at least something? That's why you deploy IPv6 dual-stacked with IPv4. That way, if two parties only speak IPv4, it's completely backwards compatible. > See the difference? Sure do I see the difference. What I don't see is how to apply any of that to the v4 to v6 transition in a way that would have any advantage over how it is being done now.