[195231] in North American Network Operators' Group
Re: Some advice on IPv6 planning and ARIN request, please
daemon@ATHENA.MIT.EDU (Mel Beckman)
Sat Jul 8 13:13:22 2017
X-Original-To: nanog@nanog.org
From: Mel Beckman <mel@beckman.org>
To: Radu-Adrian Feurdean <nanog@radu-adrian.feurdean.net>
Date: Sat, 8 Jul 2017 17:13:15 +0000
In-Reply-To: <1499533176.1218123.1034510496.04DD50F1@webmail.messagingengine.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
Radu,
Are you assuming that a goal of IPv6 is to efficiently fill subsets? I subm=
it that it is not. There are advantages to sparse address spaces, among the=
m easy mapping of MAC addresses for transition purposes and the security th=
at discourages malefactors from quickly enumerating active devices in a sub=
net.
But that's not the main reason for /64 basic subsets. One of the guiding pr=
inciples of IPv6 was to not make the mistake of underestimating the future =
applications of IP addresses. Thus your question "what hotel room has 65536=
items in it?" has no meaning in terms of future applications. As you point=
out, we're not talking about hotel rooms. We don't, by definition, know wh=
at we're talking about for future applications.
I tell people in my IPv6 classes that we have to stop thinking of ourselves=
in a spacesuit with a limited air supply that must be rationed, and instea=
d recognize that we're now in a wide-open planet-sized atmosphere where we =
can breathe freely, and without apportionment.=20
That open atmosphere was by design. It's why IPv6 uses 128-bit addresses, a=
nd not 48- or 64-bit. In the exponential space of integers, IPv6 selected a=
maximum integer that was many orders of magnitude greater than we could ev=
er imagine needing at the time.
They're just integers. Not lumps of gold. And there's more where those came=
from :)
-mel beckman
> On Jul 8, 2017, at 10:00 AM, Radu-Adrian Feurdean <nanog@radu-adrian.feur=
dean.net> wrote:
>=20
>> On Sat, Jul 8, 2017, at 03:06, Owen DeLong wrote:
>> consider a /48 per guest room as well as a /48 per hotel for the hotel
>> itself.
>=20
> I think the classfull madness of "/48 everywhere" should stop at some
> point; the "every subnet is a /64" is enough already.
>=20
> A /48 is 65536 *subnets*, with each subnet having space for what can be
> considered "unlimited" number of devices.
> A /56 already is 256 *subnets*.=20
> Now please show be a hotel room that has close to 65536 items in it
> (also tell me how much does a night in such a room cost).
> Then how many rooms may host close to 256 devices that can transmit and
> receive data ?
> And then again, at the end of the day a hotel is *NOT* and ISP, a hotel
> is a hotel. Internet access is just an extra service that became
> mandatory lately in order to remain "competitive".
