[arin-ppml] Policy Proposal: Predicable IPv4 Run Out by Prefix Size

Pete Templin petelists at templin.org
Wed Jun 10 16:46:11 EDT 2009

Scott Leibrand wrote:
> Pete Templin wrote:
>> I'm simply not following your suggestion of the numbers, which 
>> includes looking at the spreadsheet you've provided.  I'll base my 
>> discussions on the one quarter (1/4) ratio since that's what's written 
>> into the Policy Proposal.
>> Case study #1: ARIN has a /13 of space, also known as 524,288 
>> addresses.  Four large-enough requests happen to be at the head of the 
>> line, and based on the one-quarter ratio they're eligible for a /15 of 
>> space per request.  Each request is issued a /15, also known as 
>> 131,072 addresses.  These 524,288 addresses in four allocations would 
>> wipe out the pool, not the 24 allocations that you present above.
> If ARIN has a /13 of space, the first large-enough request to come in 
> could get a /15 based on a 1/4 ratio.  That would take ARIN's space down 
> to /14+/15, meaning that the second large-enough request could get a 
> /16.  That leaves /14+/15+16, which means the next few also get a /16.  
> Once the /14 gets broken up, leaving /15+16, then the next few requests 
> can only get /17, until the /15 gets broken up, at which point it goes 
> to /18, etc. etc. until you get to the minimum allocation size.

OK, now I understand the intentions.  That said, the first paragraph of 
the proposed policy needs a complete re-write, or at least the first 
sentence: "When ARIN receives its last /8, by IANA implementing section, a maximum allocation and assignment size will be put into 
effect."  This needs to be completely redone to reflect the dynamic 
nature of the ideas you're batting around.  Ideas like "sliding scale", 
"dynamic allocation/assignment size", etc. come to mind.

That said, I think this policy proposal leads to a highly-unpredictable 
run-out model at a micro (i.e. per-request) level - there would be 
essentially no way to predict how much of an assignment/allocation a 
requester might get unless there was a public status board, reports 
(rumors?) on mailing lists (yesterday I got a /X!!!), etc.  It's 
predictable run-out at a macro level, but quite unpredictable at a micro 


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