[147926] in North American Network Operators' Group
Re: subnet prefix length > 64 breaks IPv6?
daemon@ATHENA.MIT.EDU (Ray Soucy)
Wed Dec 28 07:14:23 2011
In-Reply-To: <B1B542AA-2FA8-4834-A59B-835C88812A2E@muada.com>
Date: Wed, 28 Dec 2011 07:13:30 -0500
From: Ray Soucy <rps@maine.edu>
To: Iljitsch van Beijnum <iljitsch@muada.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Wed, Dec 28, 2011 at 6:23 AM, Iljitsch van Beijnum
<iljitsch@muada.com> wrote:
> Also somehow the rule that all normal address space must use 64-bit interface
> identifiers found its way into the specs for no reason that I have ever been able
> to uncover. On the other hand there's also the rule that IPv6 is classless and
> therefore routing on any prefix length must be supported, although for some
> implementations forwarding based on > /64 is > somewhat less efficient.
This ambiguity has always bothered me. The address architecture RFC
requires a 64-bit interface identifier, but it's required to be
unenforced by implementation, which makes it more of a suggestion at
best. I think the wording should be updated to changed MUST to
SHOULD. That said, and despite my own use of prefix lengths other
than 64-bit, I do believe that a 64-bit prefix for each host network
is in our long-term interest. Not having to size networks based on
the number of hosts is a good thing. Features made possible by a
64-bit address space is a good thing.
--
Ray Soucy
Epic Communications Specialist
Phone: +1 (207) 561-3526
Networkmaine, a Unit of the University of Maine System
http://www.networkmaine.net/
