[ih] IPv8...

[Craig Partridge]

On Mon, Apr 20, 2026 at 8:15 AM Michael Grant via Internet-history <
internet-history at elists.isoc.org> wrote:

>
>
> Anyway, in the interest of the name of this list, is there some succinct
> summary of why we never deprecated ipv4 and why it will never happen?
>
>
I'm not going to speculate on "why it will never happen" (my crystal ball
has limited capabilities).   But as to why no flag day was contemplated
back in the 1990s.

Some of us remembered the (early 1983) TCP flag day (when ARPANET went to
TCP from NCP) or  had arrived in the community months later when memories
were fresh (that's me).   And the answer is that lots didn't work for weeks
after the flag day.  And by the 1990s the Internet couldn't just be put in
degraded mode for weeks or months.  (And there were lesser examples -- DNS
transitioning from hosts.txt to just using the DNS was not smooth either).
I don't recall anyone explicitly saying "no flag day" but I do recall a
strong sentiment that we need a glide path rather than simply flipping a
switch and that reflected what we'd seen in the prior dozen or so years.

Craig

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