[ppml] Proposed Policy: IPv6 HD ratio

Geoff Huston gih at apnic.net
Tue May 10 16:05:26 EDT 2005

Randy Bush wrote:
> > One of the major components of that conservation discussion has been
> > changing the HD Ratio for subsequent allocations.  The change to .94 
> from .8
> > in the proposed policy change arises from work by Geoff Huston and his
> > presentation at the ARIN XV meeting IPv6 Roundtable along with others.
> >
> > It seems to me following the various threads that there is little 
> resistance
> > to the HD Ratio change.
>i suspect that some folk may not understand all of the implications.
>heck, i probably don't.  but one would seem to be that it makes it
>even harder for the smaller folk and not too much harder for the larger.

Interestingly I would actually say that if anything the effect of the 
change in the
HD Ratio would be in the other direction.

If the level of address allocation activity over the past 5 years in IPv4 
is any
indication (and in that period we've seen boom, bust and recovery) then some
80% of the registry transactions to ISP and LIRs would be a /32 or /31
irrespective of the HD Ratio choice, while some 2% of allocations would
be larger than a /27.

Unfortunately the dynamic nature of the ARIN XV agenda meant that
a more detailed consideration of this topic was not able to happen at
that meeting. The presentation I'd prepared on this topic is at
Slide 20 provides some observations arising from this study.

One could offer the observation that changing the HD ratio makes
effectively no difference to the smaller folk, but does provide some
encouragement for the larger folk to  consider their addressing plan
with a little more care.



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