[143373] in North American Network Operators' Group
Re: IPv6 end user addressing
daemon@ATHENA.MIT.EDU (Mark Andrews)
Mon Aug 8 10:19:45 2011
To: Valdis.Kletnieks@vt.edu
From: Mark Andrews <marka@isc.org>
In-reply-to: Your message of "Mon, 08 Aug 2011 08:43:32 -0400."
<174561.1312807412@turing-police.cc.vt.edu>
Date: Tue, 09 Aug 2011 00:18:57 +1000
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
In message <174561.1312807412@turing-police.cc.vt.edu>, Valdis.Kletnieks@vt.edu
writes:
> --==_Exmh_1312807411_38980P
> Content-Type: text/plain; charset=us-ascii
>
> On Mon, 08 Aug 2011 10:15:17 +0200, Mohacsi Janos said:
>
> > - Home users - they usually don't know what is subnet. Setting up
> > different subnets in their SOHO router can be difficult. Usually the
> > simple 1 subnet for every device is enough for them. Separating some
> > devices into a separate subnets is usually enough for the most
> > sophisticated home users. If not then he can opt for business service....
>
> You don't want to make the assumption that just because Joe Sixpack doesn't
> know what a subnet is, that Joe Sixpack's CPE doesn't know either.
>
> And remember that if it's 3 hops from one end of Joe Sixpack's internal net t
> o
> the other, you're gonna burn a few bits to support heirarchical routing so yo
> u
> don't need a routing protocol. So if Joe's exterior-facing CPU gets handed a
> /56 by the provider, and it hands each device it sees a /60 in case it's a
> device that routes too, it can only support 14 devices. And if one of the
> things that got handed a /60 is a wireless access point or something, it's on
> ly
> going to be able to support 15 or so subnets. So a simple topology of only a
> half dozen devices can burn up 8 bits of subnet addressing real fast. Yes, yo
> u
> can conserve bits by being more clever, but then you probably need an IGP of
> some sort....
Which is why CPE devices shouldn't do heirarchical assignment by default.
PD supports multiple upstream requests.
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka@isc.org
