nanog mailing list archives

Re: Dual stack IPv6 for IPv4 depletion


From: Mark Andrews <marka () isc org>
Date: Wed, 15 Jul 2015 11:00:18 +1000


In message <CANjVB-jbtc4V5yba0xtGA7N5geQcz86hvydj4J9J8UxhzMMEZw () mail gmail com>
, George Metz writes:
That's all well and good Owen, and the math is compelling, but 30 years ago
if you'd told anyone that we'd go through all four billion IPv4 addresses
in anyone's lifetime, they'd have looked at you like you were stark raving
mad.

I did that math ~30 years ago '88, when I got my first address
blocks, and realised that IPv4 wasn't sustainable then.

That's what's really got most of the people who want (dare I say more
sane?) more restrictive allocations to be the default concerned; 30 years
ago the math for how long IPv4 would last would have been compelling as
well, which is why we have the entire Class E block just unusable and large
blocks of IP address space that people were handed for no particular reason
than it sounded like a good idea at the time.

We don't use Class E because were using up IPv4 space too quickly
to make it worthwhile to make it work cleanly for everyone.  Note
also the other 7/8ths the IPv6 space is reserved for unicast
addresses.  Class E was reserved for experimentation so in reality
there is no comparison.

It's always easier to be prudent from the get-go than it is to rein in the
insanity at a later date. Just because we can't imagine a world where IPv6
depletion is possible doesn't mean it can't exist, and exist far sooner
than one might expect.

How many sites per person on the planet do you see in use in a 100
years, 1000 years.  Out of this 1/8th there is around 350 per /
person with /48's.

On Tue, Jul 14, 2015 at 12:22 AM, Owen DeLong <owen () delong com> wrote:

How so?

There are 8192 /16s in the current /3.

ISPs with that many pops at 5,000,000 end-sites per POP, even assuming 32
end-sites per person
can=E2=80=99t really be all that many=E2=80=A6


25 POPS at 5,000,000 end-sites each is 125,000,000 end-sites per ISP.

7,000,000,000 * 32 =3D 224,000,000,000 / 125,000,000 =3D 1,792 total /16s
consumed.

Really, if we burn through all 8,192 of them in less than 50 years and I=
=E2=80=99m
still alive
when we do, I=E2=80=99ll help you promote more restrictive policy to be e=
nacted
while we
burn through the second /3. That=E2=80=99ll still leave us 75% of the add=
ress
space to work
with on that new policy.

If you want to look at places where IPv6 is really getting wasted, let=E2=
=80=99s
talk about
an entire /9 reserved without an RFC to make it usable or it=E2=80=99s pa=
rtner /9
with an
RFC to make it mostly useless, but popular among those few remaining NAT
fanboys. Together that constitutes 1/256th of the address space cast off =
to
waste.

Yeah, I=E2=80=99m not too worried about the ISPs that can legitimately ju=
stify a
/16.

Owen

On Jul 13, 2015, at 16:16 , Joe Maimon <jmaimon () ttec com> wrote:



Owen DeLong wrote:
JimBob=E2=80=99s ISP can apply to ARIN for a /16

Like I said, very possibly not a good thing for the address space.


-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka () isc org


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