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by adrian_b 179 days ago
An explicit goal of IPv6 considered as important as the address expansion was the simplification of the packet header, by having fewer fields and which are correctly aligned, not like in the IPv4 header, in order to enable faster hardware routing.

The scheme described by you fails to achieve this goal.
1 comments
mike_d 179 days ago
I am glad you brought this up, that is another big issue with IPv6. A lot of the problems it was trying to solve literally don't exist anymore.

Header processing and alignment were an issue in the 90s when routers repurposed generic components. Now we have modern custom ASICs that can handle IPv4 inside of a GRE tunnel on a VLAN over MPLS at line rate. I have switches in my house that do 780 Gbps.

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adrian_b 178 days ago
It is irrelevant what we can do now.

At the time when it was designed, IPv6 was well designed, much better than IPv4, which was normal after all the experience accumulated while using IPv4 for many years.

The designers of IPv6 have made only one mistake, but it was a huge mistake. The IPv4 address space should have been included in the IPv6 space, allowing transparent intercommunication between any IP addresses, regardless whether they were old IPv4 addresses or new IPv6 addresses.

This is the mistake that has made the transition to IPv6 so slow.

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throw0101c 178 days ago
> The IPv4 address space should have been included in the IPv6 space […]

See IPv4-mapped ("IPv4-compatible") IPv6 addresses from RFC 1884 § 2.4.4 (from 1995) and follow-on RFCs:

* https://datatracker.ietf.org/doc/html/rfc1884

* https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresse...

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yjftsjthsd-h 178 days ago
> The IPv4 address space should have been included in the IPv6 space, allowing transparent intercommunication between any IP addresses, regardless whether they were old IPv4 addresses or new IPv6 addresses.

How would you have implemented it that is different from the NAT64 that actually exists, including shoving all IPv4 addresses into 64:ff9b::/96?

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zajio1am 178 days ago
Ideally, 464XLAT should have been there from the beginning and its host part (CLAT) should have been a mandatory part of IP stack.
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