[118241] in North American Network Operators' Group
Re: ISP customer assignments
daemon@ATHENA.MIT.EDU (Michael Dillon)
Thu Oct 15 19:52:13 2009
In-Reply-To: <20091014024957.GD612455@hiwaay.net>
Date: Fri, 16 Oct 2009 00:51:21 +0100
From: Michael Dillon <wavetossed@googlemail.com>
To: Chris Adams <cmadams@hiwaay.net>, NANOG <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> Of course, with IPv4, you never assigned a large enough block to begin
> with that would anticipate all growth, so routing additional blocks was
> a lot easier than changing blocks, cleaner than secondary IPs
> multiplying like crazy, etc., etc. =A0None of that would be an issue with
> a single /64.
You've hit on the key difference of IPv6. With IPv6 you should design
your network
so that it can grow for a long time without increasing the address
block sizes anywhere.
A /64 will work for even the biggest subnets. A /48 will do for for
very, very big sites.
And only the largest ISPs will outgrow a /32 allocation. If you assign a /4=
8 to
a data center site, then when you subnet it, try to maintain that growth ab=
ility
if you can. Don't skimp on address block sizes unless you are backed into
a corner for technical or business reasons.
--Michael Dillon
