Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast

John Gilmore gnu at toad.com
Fri Nov 19 01:15:36 UTC 2021


Fred Baker <fredbaker.ietf at gmail.com> wrote:
> My observation has been that people don't want to extend the life of
> IPv4 per se; people want to keep using it for another very short time
> interval and then blame someone else for the fact that the 32 bit
> integers are a finite set.

It's an attractive strawman, but knocking it down doesn't
contribute to the discussion.

I am not blaming anybody for the finity of 32-bit integers.

Nor am I trying to extend the lifetime of IPv4, for either a short or a
long time.  Personally, I think that IPv4 will already be with us for
the rest of my lifetime.  Its life will already extend beyond mine,
without any effort on my part.  It was a good design, and it will
outlive its makers.  The people who in 2008 predicted that it was
senseless to improve IPv4 because it would be dead by 2018, were
objectively wrong, because it's not dead.

IETF did what the objectors said, back in 2008: They didn't improve
IPv4, on the exact theory that effort would go into IPv6 instead.  Hmm.
13 years later, that decision did not cause IPv6 to take over the world
and obsolete IPv4.  IPv4 is still here, and the improvements that would
have been fully rolled out to the user base by now, if standardized in
2008, are still missing.  Perhaps we should reconsider that wrong
advice, rather than regurgitate the same decision every time the issue
is raised?

> If you don't think that's a true statement, I'd be very interested to
> hear what you think might be true.

IPv6 is still on a remarkable if not meteoric growth ramp; in the last
year it's gone from 30% to 34% of the Internet, according to Google.
There is no need to cut off IPv4 maintenance at the knees in order to
make IPv6 look good.  We can make both v4 and v6 better, and let people
choose which one(s) they prefer to use.

That's what I think might be true about why simple low-risk tweaks that
make IPv4 better are not an obviously stupid tactic.

As Brian Carpenter has been saying for 15+ years, IPv4 and IPv6 don't
have a transition strategy, they have a co-existence strategy.
Neglecting or abandoning IPv4 is not a useful part of that strategy.

Keeping the price of IPv4 addresses reasonable means that dual-stack
servers can continue to be deployed at reasonable cost, so that it
doesn't matter whether clients have IPv6 or IPv4.  Any company that put
its services on IPv6-only sites today would be cutting off 65% of their
potential customers.  Even if v6 had 90% of the market, why would a
company want 10% of its prospects to be unable to reach its service?

(Big companies who run massive public-facing server farms are the
biggest buyers of IPv4 addresses in the market, spending hundreds of
millions of dollars every year.  Amazon, Google, Alibaba, Microsoft,
etc.  They are already running IPv6, and all their servers already have
free IPv6 addresses from a RIR.  Why are they spending that money?
It isn't because they are stupid doodooheads who hate IPv6.)

As Fred points out, this issue has been discussed since 2008.  IETF also
faced it in 2014-2018 in the now-sunsetted "sunset4" working group.
That group wrote a bunch of drafts proposing to disable or sunset IPv4.
None of these became RFCs.  They didn't pass the sniff test.  They
weren't what users and customers wanted.

The issue keeps coming back because the wrong decision keeps getting
offered: "Just switch everybody to use IPv6, and if they won't, then
deny their proposals for IPv4."  Another way of putting it was proposed
by Dave Thaler: "Rather than changing any existing software (OS's or
apps) to allow class E addresses, the effort would be better spent
towards getting more IPv6 deployment."

This is not an objection to deploying reserved addresses in IPv4, it is
a plea for more IPv6 deployment.  It is like saying, "Do not spend your
time fixing the environment, instead we need to fix the political
system."

It is a hopeless plea, since "allowing Class E addresses" and "more IPv6
deployment" are not the only two possible goals to put forth effort on.
Merely stopping work on one, will not cause the other to be advanced.
There must be a name for this fallacious argument...thank you, Wikipedia,
it's a "false dilemma":

  https://en.wikipedia.org/wiki/False_dilemma

The two goals can proceed in parallel, and many of the people who would
happily do Goal 1 are not in any position to affect Goal 2 -- just as
with the environment and politics.

It's pretty simple to understand why IPv6 has not taken over the world
yet.  IPv4 got rapid adoption because it was so much better than all the
alternatives available at the time.  IPv6 would have gotten equally
rapid adoption if it had been the thing so much better than all the
alternatives.  IPv6 is not getting that rapid adoption today, because it
has to compete with the already pervasive IPv4.  IPv4 is better in one
key way: everybody you want to talk with is already there.  (It's akin
to the issue of why can't people just switch to a better social network
than Facebook?  They can, but everybody else they want to talk with is
already on Facebook.)

There is no need to cut off IPv4 maintenance at the knees in order to
make IPv6 look good.  Simple, low-risk tweaks that make IPv4 better are
not a stupid thing to do.

	John


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