[114287] in North American Network Operators' Group
DHCPv6 PD
daemon@ATHENA.MIT.EDU (David W. Hankins)
Tue May 5 16:19:51 2009
Date: Tue, 5 May 2009 13:20:03 -0700
From: "David W. Hankins" <David_Hankins@isc.org>
To: nanog@nanog.org
In-Reply-To: <4A00982D.1060209@brightok.net>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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On Tue, May 05, 2009 at 02:49:01PM -0500, Jack Bates wrote:
> Sure, but how does the router know it needs to hand out a /62? Then what=
=20
> about the router after that? Does it hand out a /61? then the router behi=
nd=20
> that?
In IA_NA's, there is a (undocumented in RFC 3315) convention to permit
a client to supply an IAADDR with a zeroed address. This convention
allows the client to supply preferred and valid lifetime hints without
knowing a specific address it would like.
I see no reason why a similar convention can't take root here; the
bottom-most client supplies an IAPREFIX in its IA_PD with a zeroed
network number, and the desired prefix length (suppose: /64 for its
one downstream interface). The next hop combines the sum total of
bitspaces required by its clients and presents a suitable requested
size upstream (with memory, and resizing/renumbering as you go).
> What if the ISP only gave a /60?
Then someone gets a STATUS_NoAddrsAvail.
--=20
David W. Hankins "If you don't do it right the first time,
Software Engineer you'll just have to do it again."
Internet Systems Consortium, Inc. -- Jack T. Hankins
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