[ppml] IPv6>>32

[Geoff Huston]

>
> >  We should at this point be
> > striving to instill some broad confidence in the proposition that we can
> > provide a stable and enduring platform for the world's communications
> > needs.
>
>By your own numbers changing the H-D policy would get us to centuries in the
>current /3, then folding in the non-technical business desires to
>differentiate based on prefix length we are talking about multiple millennia
>still using the 64/64 split.


Again referring to the presentation at the ARIN VX IPv6 roundtable what was 
presented was the theme that a change in the HD ratio and an additional 
setting in the subnet space of 56 bits would appear to gain us all some 10 
bits  (or thereabouts) of address space - which would certainly be an 
adequate margin to dispel many lingering levels of discomfort with the 
total capacity of the address architecture without imposing undue levels of 
imposition or cost on the current and potential user population - these are 
after all relatively minor adjustments on the supply side rather than 
changes to the address architecture itself.

The 64/64 split is not quite in the same category here, and there is an 
impact on the current address architecture. Its true that the original 
motivations for this particular aspect of the address architecture have 
largely gone away, or at least have been unable to be realized, and the 
residual reasons for its adoption are based more in legacy conformance than 
in true utility. But here its not quite so clear to me that change is 
necessary. As Thomas Narten has said, maybe it would be more practical to 
go after the low hanging fruit here, when referring to a preference to look 
at the HD Ratio and the subnet size points over looking at the 64 bit split 
point between local identification and routing identifiers.

regards,

     Geoff