Re: [address-policy-wg] 2005-01 - Last Call for Comments (HD-ratio Proposal)

[Rene Wilhelm wilhelm@localhost]

Hi Geoff,

> I was also surprised by this number [46%] when I first saw it in the output.

Your number is higher, but the analysis I did also showed HD ratio could
have a significant impact on the address space consumption.
(http://www.ripe.net/ripe/policies/proposals/comments/impact_of_hd.html
 posted on this list some weeks ago) 

Looking at all invidual allocations done by RIPE NCC between 2003 and 2006,
we modelled the observed growth to a policy which used HDR 0.96 instead
of 80% utilisation as the criterium for an LIR to be eligible to receive an
additional allocation.  Starting 1/1/2003 and stepping through time the
simulation thus determined the address space held by each LIR on a day by
day basis.  By 1/1/2006 this resulted in some 60 million (about 30% of
the total) more addresses allocated compared to what we actually had
handed out under the 80% rule.

Reading your report, I believe one of the reasons our numbers differ
is that you are simulating 10,000 allocations; my analysis only looked at
the 5,121 allocations done by RIPE NCC in 2003-2006. Since the effects of
HD ratio are progressive, the more allocations you simulate, the higher the
relative increase in address space consumption becomes.


> This experiment has been repeated 1,000 times in order to determine a
> stable average value for the relative increase in address consumption
> corresponding to a change in the address allocation policies from uniform
> 80% to an HD Ratio of 0.96, assuming constant demand for addresses.

To get a feeling of how stable your average is, could you indicate
what the variation, the standard deviation in these 1,000 repeats is?
i.e. did all 1000 give you a number close to 46% or were they 
spread out a lot?


> A related consideration is that of the adoption of such a policy proposal
> by all 5 RIRs. 

From http://www.arin.net/policy/proposals/proposal_archive.html
I understand ARIN already abandoned two proposals to use HD ratio for
IPv4 allocations (nrs. 2004-2 and 2003-10).

Regards,

-- Rene



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Rene Wilhelm	        	       RIPE Network Coordination Centre 
Email: wilhelm@localhost 	       Amsterdam, the Netherlands
Phone: +31 20 535 4417		       Fax: +31 20 535 4445
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