[182352] in North American Network Operators' Group
Re: Dual stack IPv6 for IPv4 depletion
daemon@ATHENA.MIT.EDU (Owen DeLong)
Wed Jul 15 12:20:31 2015
X-Original-To: nanog@nanog.org
From: Owen DeLong <owen@delong.com>
In-Reply-To: <CANjVB-j1sqAegk_68Fw+u=f=84tDCQuL0awpejYF3d7LfZQDcg@mail.gmail.com>
Date: Wed, 15 Jul 2015 09:20:25 -0700
To: George Metz <george.metz@gmail.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
> On Jul 15, 2015, at 08:20 , George Metz <george.metz@gmail.com> wrote:
>=20
> Reasonability, like beauty, is in the eye of the beholder, but I thank =
you
> for the compliment. :)
>=20
> The short answer is "yes, that constitutes being prudent". The longer
> answer is "it depends on what you consider the wildest dreams".
>=20
> There's a couple of factors playing in. First, look at every /64 that =
is
> assigned as an IPv4 /32 that someone is running NAT behind. This is =
flat
> out WRONG from a routing perspective, but from an allocation =
perspective,
> it's very much exactly what's happening because of SLAAC and the =
48-bit MAC
> address basis for it. Since /64 is the minimum, that leaves us with =
less
> than half of the available bit mask in which to hand out that 1/8th =
the
> address space. Still oodles of addresses, but worth noting and is =
probably
> one reason why some of the "conservationists" react the way they do.
Then they are being silly. The thinking for IPv6 was a 64-bit address in =
toto
until SLAAC was proposed and 64 bits were added to enable that.
Even at 64 bits, you have more than 4 billion times as many network =
numbers as you
had host numbers in all of IPv4.
> Next, let's look at the wildest dreams aspect. The current =
"implementation"
> I'm thinking of in modern pop culture is Big Hero 6 (the movie, not =
the
> comics as I've never read them). Specifically, Hiro's "microbots". =
Each one
> needs an address to be able to communicate with the controller device. =
Even
> with the numbers of them, can probably be handled with a /64, but =
you'd
> also probably want them in separate "buckets" if you're doing =
separated
> tasks. Even so, a /48 could EASILY handle it.
Right=E2=80=A6
> Now make them the size of a large-ish molecule. Or atom. Or protons.
> Nanotech or femtotech that's advanced enough gets into Clarke's Law - =
any
> sufficiently advanced technology is indistinguishable from magic - but =
in
> order to do that they need to communicate. If you think that won't be
> possible in the next 30 years, you probably haven't been paying =
attention.
Sure, but do you really think that IPv6 can handle that in all the other =
ways?
I think we=E2=80=99ll need a new protocol to do that for reasons other =
than address
space limitations well before we run out of IPv6 addresses.
> However, that's - barring a fundamental breakthrough - probably a =
decade or
> two off. Meanwhile we've got connected soda cans to worry about.
True.
> I wrote my email as a way of pointing out that maybe the concerns (on =
both
> sides)- aren't baseless, but at the same time maybe there's a way to =
split
> the difference. It's not too much of a stretch to see that, soon, 256
> subnets may not actually be enough to deal with the connected world =
and
> "Internet of Things" that's currently being developed. But would 1024? =
How
> about 4096? Is there any need in the next 10-15 years for EVERYONE to =
be
> getting handed 65,536 /64 subnets? Split the difference, go with a /52 =
and
> suddenly you've got FOUR THOUSAND subnets for individual users so that
> their soda cans can tell the suspension on their car that it's been =
opened
> and please smooth out the ride.
There are two ways to waste addresses. One is to allocate them to users =
who
don=E2=80=99t actually use all of them.
The other is to keep them on the shelf in the free pool until well past =
the useful
life of the protocol.
I don=E2=80=99t see splitting the difference at /52 as being any more =
useful than leaving
it at /48. Certainly it is an incremental improvement over /56 and =
wildly better
than /60, but it remains an unnecessarily inferior solution.
> Frankly, both sides seem intent on overkill in their preferred =
direction,
> and it's not particularly hard to meet in the middle.
Perhaps, but it=E2=80=99s also not hard to do harmful things with the =
best of intent.
Owen
>=20
> On Tue, Jul 14, 2015 at 8:38 PM, Doug Barton <dougb@dougbarton.us> =
wrote:
>=20
>> On 7/14/15 6:23 AM, George Metz wrote:
>>=20
>>> 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.
>>>=20
>>=20
>> I've been trying to stay out of this Nth repetition of the same
>> nonsensical debate, since neither side has anything new to add. =
However
>> George makes a valid point, which is "learn from the mistakes of the =
past."
>>=20
>> So let me ask George, who seems like a reasonable fellow ... do you =
think
>> that creating an addressing plan that is more than adequate for even =
the
>> wildest dreams of current users and future growth out of just 1/8 of =
the
>> available space (meaning of course that we have 7/8 left to work with
>> should we make a complete crap-show out of 2000::/3) constitutes =
being
>> prudent, or not?
>>=20
>> And please note, this is not a snark, I am genuinely interested in =
the
>> answer. I used to be one of the people responsible for the prudent =
use of
>> the integers (as the former IANA GM) so this is something I've put a =
lot of
>> thought into, and care deeply about. If there is something we've =
missed in
>> concocting the current plan, I definitely want to know about it.
>>=20
>> Even taking into account some of the dubious decisions that were made =
20
>> years ago, the numbers involved in IPv6 deployment are literally so
>> overwhelming that the human brain has a hard time conceiving of them.
>> Combine that with the conservation mindset that's been drilled into
>> everyone regarding IPv4 resources, and a certain degree of =
over-enthusiasm
>> for conserving IPv6 resources is understandable. But at the same =
time,
>> because the volume of integers is so vast, it could be just as easy =
to slip
>> into the early-days v4 mindset of "infinite," which is why I like to =
hear a
>> good reality check now and again. :)
>>=20
>> Doug
>>=20
>> --
>> I am conducting an experiment in the efficacy of PGP/MIME signatures. =
This
>> message should be signed. If it is not, or the signature does not =
validate,
>> please let me know how you received this message (direct, or to a =
list) and
>> the mail software you use. Thanks!
>>=20
>>=20
