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 about the router after that? Does it hand out a /61? then the router behind 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. -- 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