[186499] in North American Network Operators' Group
Re: Nat
daemon@ATHENA.MIT.EDU (Mike Hammett)
Sun Dec 20 11:57:55 2015
X-Original-To: nanog@nanog.org
Date: Sun, 20 Dec 2015 10:57:49 -0600 (CST)
From: Mike Hammett <nanog@ics-il.net>
Cc: North American Network Operators' Group <nanog@nanog.org>
In-Reply-To: <8D2BAAA5-C96E-4BD0-BB4F-D00218D17F9A@corbe.net>
Errors-To: nanog-bounces@nanog.org
There's nothing that can really be done about it now and I certainly wasn't=
able to participate when these things were decided.=20
However, keeping back 64 bits for the host was a stupid move from the begin=
ning. We're reserving 64 bits for what's currently a 48 bit number. You can=
use every single MAC address whereas IPS are lost to subnetting and other =
such things. I could have seen maybe holding back 56 bits for the host if f=
or some reason we need to replace the current system of MAC addresses at so=
me point before IPv6 is replaced.=20
There may be address space to support it, but is there nimble boundary spac=
e for it?=20
The idea that there's a possible need for more than 4 bits worth of subnets=
in a home is simply ludicrous and we have people advocating 16 bits worth =
of subnets. How does that compare to the entire IPv4 Internet?=20
There is little that can be done about much of this now, but at least we ca=
n label some of these past decisions as ridiculous and hopefully a lesson f=
or next time.=20
-----=20
Mike Hammett=20
Intelligent Computing Solutions=20
http://www.ics-il.com=20
----- Original Message -----
From: "Daniel Corbe" <corbe@corbe.net>=20
To: "Mike Hammett" <nanog@ics-il.net>=20
Cc: "Mark Andrews" <marka@isc.org>, "North American Network Operators' Grou=
p" <nanog@nanog.org>=20
Sent: Saturday, December 19, 2015 10:55:03 AM=20
Subject: Re: Nat=20
Hi.=20
> On Dec 19, 2015, at 11:41 AM, Mike Hammett <nanog@ics-il.net> wrote:=20
>=20
> "A single /64 has never been enough and it is time to grind that=20
> myth into the ground. ISP's that say a single /64 is enough are=20
> clueless."=20
>=20
>=20
>=20
> LLLLOOOOOOLLLLL=20
>=20
>=20
> A 100 gallon fuel tank is fine for most forms of transportation most peop=
le think of. For some reason we built IPv6 like a fighter jet requiring eve=
ryone have 10,000 gallon fuel tanks... for what purpose remains to be seen,=
if ever.=20
>=20
>=20
You=E2=80=99re being deliberately flippant.=20
There are technical reasons why a single /64 is not enough for an end user.=
A lot of it has to do with the way auto configuration works. The lower 64 =
bits of the IP address are essentially host entropy. EUI-64 (for example) i=
s a 64 bit number derived from the mac address of the NIC.=20
The requirement for the host portion of the address to be 64 bits long isn=
=E2=80=99t likely to change. Which means a /64 is the smallest possible pre=
fix that can be assigned to an end user and it limits said end user to a si=
ngle subnet.=20
Handing out a /56 or a /48 allows the customer premise equipment to have mu=
ltiple networks behind it. It=E2=80=99s a good practice and there=E2=80=99s=
certainly enough address space available to support it.=20
