ISP customer assignments

Tim Chown tjc at
Mon Oct 5 21:09:34 UTC 2009

On Mon, Oct 05, 2009 at 11:34:51AM -0700, Wayne E. Bouchard wrote:
> Am I the only one that finds this problematic? I mean, the whole point
> of moving to a 128 bit address was to ensure that we would never again
> have a problem of address depletion. Now I'm not saying that this puts
> us anywhere in that boat (yet) but isn't saying "oh, lets just put a
> /64 on every interface" pretty well ignoring the lessons of the last
> 20 years? Surely a /96 or even a /112 would have been just as good.

The current guidance applies only to one /3 out of eight.  Different
rules could be applied to the others.

> Like I said, I'm not necessarily saying we're going to find ourselves
> in that boat again but it does seem as though more thought is
> required. (And yes, I fully realize the magnitude of 2^64. I also
> fully realize how quickly inexhaustable resources become rationable.)

As it happens, Windows boxes now generate random interface IDs (not
based on MACs), which could have easily been 32 bits with the default
subnet 96 bits long, rather than 64 bits.   But we are where we are 
and we do have interesting ideas like CGAs as a result.


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