quietly....

Geoff Huston gih at apnic.net
Wed Feb 2 00:45:12 CST 2011


On 02/02/2011, at 1:11 PM, Owen DeLong wrote:

> 
> On Feb 1, 2011, at 3:54 PM, Lee Howard wrote:
> 
>>> "People won't be able to access our site"
>>> sure helps but being unable to put a date on it still reduces incentive
>>> (especially when Management get involved, and especially if there is a
>>> financial outlay involving firewalls etc.).  
>> 
>> Geoff generously provided a probabilistic sense for RIR runout:
>> http://www.potaroo.net/tools/ipv4/rir.jpg
>> Pick your RIR and plot its runout date.  If it's ARIN, then the first
>> ISP is out of IPv4 addresses at most three months later (since ARIN 
>> now allocates for three months' need).  Of course, if demand increases,
>> these dates might change.
>> 
>> Will users be unable to reach your content on $RIR_runout_date + 3?
>> They might have to get there through large-scale NAT.  That might
>> bother management if you rely on IP geo-location, or need to 
>> initiate connections downstream, or rate limit per IP address, or
>> have anti-DOS techniques measuring hits per source IP address, 
>> or have employees VPN in, or need to report intrusions, or any of
>> the many problems widely documented.
>> 
>> Oh, and when I said to pick your RIR, I meant the RIR of users
>> who access your content.
>> 
>> Lee
>> 
> 
> I think there is a key problem with Geoff's graph.
> 
> I think it fails to take into account the transitive probability of requests
> among the largest 3 regions. I agree that APNIC will probably run
> just about exactly as he predicts. I think, however, that the runout
> at APNIC will create a higher demand in ARIN and RIPE. Once that
> happens, their runout dates will get moved up much closer to
> the runout date of APNIC. As soon as the second of the three
> runs out, the remaining one will get another burst of acceleration.
> 
> It does not appear to me that this probability is accounted for in the
> plots.
> 
> Owen
> 
> (Including Geoff because it's not fair to criticize his work behind his back)

Yes - a certain (X) percent of demand will shift out from a region once that region's stocks are depleted. What value X realistically takes is not something I can factor into these models, nor can I predict where this unmet demand may surface in the remaining regions. 

The future of IPv4 contains many uncertainties.

  Geoff









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