[135435] in North American Network Operators' Group
Re: IPv6: numbering of point-to-point-links
daemon@ATHENA.MIT.EDU (Tim Durack)
Tue Jan 25 10:26:39 2011
In-Reply-To: <FC64B3384195884588D252343702D23F0185477C@ICABEXCCLU01B.int.sonofon.dk>
Date: Tue, 25 Jan 2011 10:25:56 -0500
From: Tim Durack <tdurack@gmail.com>
To: Lasse Jarlskov <laja@telenor.dk>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Tue, Jan 25, 2011 at 9:44 AM, Lasse Jarlskov <laja@telenor.dk> wrote:
> Thank you all for your comments - it appears that there is no consensus
> on how this should be done.
The best piece of advice I received when asking similar questions in
the past is to allocate a /64 for every network regardless of it's
potential size. Loopbacks, point-to-point, hosting VLANs etc. Then
assign whatever size you are currently comfortable with.
We've used /128s for loopbacks, safe in the knowledge that we can
expand them all to /64s without renumbering (in case someone comes up
with a good idea why /64s on loopbacks are necessary.)
We've gone unnumbered on point-to-points, as a way of deferring that
particular decision. Admittedly this reduces useful diagnostics
available from traceroutes, although I quite like seeing loopbacks in
traceroutes anyway. Unnumbered does reduce control-plane address space
surface, which might be seen as a useful benefit (I'm sure someone
will tell me why that's a bad idea.)
My point is, if you do your number plan right, you should have some
flexibility to make changes in the future without pain.
--
Tim:>
