[165978] in North American Network Operators' Group
Re: minimum IPv6 announcement size
daemon@ATHENA.MIT.EDU (Joe Abley)
Fri Sep 27 10:55:25 2013
From: Joe Abley <jabley@hopcount.ca>
In-Reply-To: <alpine.OSX.2.02.1309271038350.894@brugal.local>
Date: Fri, 27 Sep 2013 10:54:48 -0400
To: Brandon Ross <bross@pobox.com>
Cc: Ryan McIntosh <rmcintosh@nitemare.net>, bmanning@vacation.karoshi.com,
NANOG <nanog@nanog.org>, Darren Pilgrim <nanog@bitfreak.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 2013-09-27, at 10:40, Brandon Ross <bross@pobox.com> wrote:
> On Fri, 27 Sep 2013, Ryan McIntosh wrote:
>=20
>> It's a waste, even if we're "planning for the future", no one house
>> needs a /64 sitting on their lan.. or at least none I can sensibly
>> think of o_O.
>=20
> Okay, I'm just curious, what size do you (and other's of similar =
opinion) think the IPv6 space _should_ have been in order to allow us to =
not have to jump through conservation hoops ever again? 128 bits isn't =
enough, clearly, 256? 1k? 10k?
Given the design decision to use the bottom 64 bits to identify an =
individual host on a broadcast domain, the increase in address size =
isn't really 32 bits to 128 bits -- if your average v4 subnet size for a =
vlan is a /27, say, then it's more like an increase of 27 bits to 64 =
bits from the point of view of global assignment.
Alternatively, considering that it's normal to give a service provider =
at least a /32, whereas the equivalent assignment in v4 might have been =
something like a /19 (handwave, handwave), it's more like an increase of =
13 bits to 32 bits.
Alternatively, considering that it's considered reasonable in some =
quarters to give an end-user a /48 so that they can break out different =
subnets inside their network whereas with IPv4 you'd give a customer a =
single address and expect them to use NAT, then it's more like an =
increase of 31 bits to 48 bits.
That's still a lower bound of 2^17 times as many available addresses, =
and having enough addresses to satisfy a network 131,072 times as big as =
the current v4 Internet does not seem like a horrible thing. But the =
oft-repeated mantra that "there are enough addresses to individually =
number every grain of sand on the world's beaches" doesn't describe =
reality very well.
The IPv6 addressing plan didn't wind up meeting our requirements very =
well. Film at 11.
Joe=
