[128073] in North American Network Operators' Group
Re: Addressing plan exercise for our IPv6 course
daemon@ATHENA.MIT.EDU (Owen DeLong)
Sat Jul 24 04:44:20 2010
From: Owen DeLong <owen@delong.com>
In-Reply-To: <4C49FB03.2030104@matthew.at>
Date: Sat, 24 Jul 2010 01:40:19 -0700
To: matthew@matthew.at
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Jul 23, 2010, at 1:26 PM, Matthew Kaufman wrote:
> sthaug@nethelp.no wrote:
>>> It is not about how many devices, it is about how many subnets, =
because you
>>> may want to keep them isolated, for many reasons.
>>>=20
>>> It is not just about devices consuming lots of bandwidth, it is also =
about
>>> many small sensors, actuators and so.
>>> =20
>>=20
>> I have no problems with giving the customer several subnets. /56 is
>> just fine for that.
> /56? How about /62? That certainly covers "several"... and if you're =
really worried they might have too many subnets for that to work, how =
about /60?
/60 at a bare minimum since you can do RDNS delegation on /x boundaries =
where x%4=3D=3D0.
RDNS for a /62 is do-able, but, it requires 4 zone files and 4 sets of =
parent NS records instead of 1.
/62 for 4 customers ends up requiring 16 zone files and 16 sets of =
parent NS records instead of 4.
>> I haven't seen any kind of realistic scenarios
>> which require /48 for residential users *and* will actually use lots
>> and lots of subnets - without requiring a similar amount of manual
>> configuration on the part of the customer.
>>=20
>> So we end up with /56 for residential users.
>> =20
> Only because people think that the boundaries need to happen at =
easy-to-type points given the textual representation. /56 is still =
overkill for a house. And there's several billion houses in the world to =
hook up.
>=20
Yes... Overkill is a good thing in IPv6. Even with this level of =
overkill, fully deploying the current world with a /48 for every house =
consumes less than 0.1% of the address space.
(Apprximately 4x10^9 households on earth getting a /48 each =3D roughly =
one /16 which is 1/65,536th of the total address space and 1/8192nd of =
2000::/3)
What is the harm in doing so?
Why not minimize provisioning effort and maximize user flexibility by =
consuming a very tiny fraction of a plentiful resource which costs =
virtually nothing?
Owen
