quietly....

Owen DeLong owen at delong.com
Tue Feb 1 20:11:08 CST 2011


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)





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