[181888] in North American Network Operators' Group
Re: Dual stack IPv6 for IPv4 depletion
daemon@ATHENA.MIT.EDU (Owen DeLong)
Thu Jul 9 03:13:56 2015
X-Original-To: nanog@nanog.org
From: Owen DeLong <owen@delong.com>
In-Reply-To: <559DA57B.90000@lugosys.org>
Date: Wed, 8 Jul 2015 18:15:30 -0700
To: "Israel G. Lugo" <israel.lugo@lugosys.org>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
> On Jul 8, 2015, at 15:34 , Israel G. Lugo <israel.lugo@lugosys.org> =
wrote:
>=20
>=20
> On 07/05/2015 06:26 PM, Owen DeLong wrote:
>>> On Jul 4, 2015, at 23:51 , Valdis.Kletnieks@vt.edu wrote:
>>>=20
>>> Put their IPv4 behind a NAT and a globally routed /56.
>>>=20
>>> There, FTFY. :)
>> Or better yet globally routed /48.
>>=20
>> /56 is still a bad idea.
>>=20
>> Owen
> I've read this many times and am aware it's the standard =
recommendation.
> Makes perfect sense for the customer side, as it would be hard for him
> to subnet properly otherwise.
>=20
> Doesn't seem to make sense at all for the ISP side, though. Standard
> allocation /32. Giving out /48s. Even if we leave out proper subnet
> organization and allocate fully densely, that's at most 65,536 =
subnets.
> Not a very large ISP.
If you=E2=80=99re trying to build a decent sized ISP in a /32, you=E2=80=99=
re doing it wrong.
/32 is not the =E2=80=9Cstandard size=E2=80=9D =E2=80=94 It=E2=80=99s =
the MINIMUM size.
>=20
> You can say "get more blocks", or "get larger blocks". Sure, let's =
give
> each ISP a /24. That lets them have up to 16M customers (and that's
> still subnetting densely, which sucks rather a lot). Doesn't leave =
that
> many allocation blocks for the RIRs to hand out, though.
If you really think we have 16.7 Million ISPs on the planet, I think you
badly miscounted. In fact, if you think we have 1 million ISPs that have
more than 1 million customers, I=E2=80=99d say you=E2=80=99ve badly =
miscounted something.
What am I missing?
In terms of ISPs that need to support 16M customers, let=E2=80=99s =
assume everyone
on the planet has 32 ISP subscriptions of some form or another. (work, =
home,
tablet, phone, dongle, whatever=E2=80=A6 I=E2=80=99m pretty sure 32 is =
generous).
Let=E2=80=99s assume EVERYONE on the planet is connected.
That=E2=80=99s 7 Billion * 32 =3D 224 Billion total customers.
Now let=E2=80=99s sparse-allocate 24s at the rate of 4 million customers =
per /24.
224,000,000,000 / 4,000,000 =3D 56,000
We need a total of 56,000 /24s to cover the total population.
That still leaves us with 16,721,216 /24s. We barely made a dent in the
number of /24s.
Please explain to me again where the problem is with handing out /48s?
> People usually look at IPv6 and focus on the vast numbers of =
individual
> addresses. Naysayers usually get shot down with some quote mentioning
> the number of atoms in the universe or some such. Personally, I think
> that's a red herring; the real problem is subnets. At this rate I
> believe subnets will become the scarce resource sooner or later.
I=E2=80=99ve done the math on the prefix side. See above=E2=80=A6 =
Clearly you haven=E2=80=99t.
> Sure, in the LAN side we'll never have to worry about address =
scarcity.
> But what's the point of having addresses to spare, if it just means
> you've got to start worrying about subnet scarcity? If the goal was
> never having to worry about counting anymore, I propose that 128 bits =
is
> far too little. Should've gone a full 256 and be done with it.
Respectfully, I think that the math above shows that you are not correct
in this assertion.
Owen
