On 24/04/2013, at 8:10 AM, Andrew Latham <lath...@gmail.com> wrote: > On Tue, Apr 23, 2013 at 5:41 PM, Valdis Kletnieks > <valdis.kletni...@vt.edu> wrote: >> I didn't see any mention of this Tony Hain paper: >> >> http://tndh.net/~tony/ietf/ARIN-runout-projection.pdf >> >> ARIN predicted to run out of IP space to allocate in August this year. >> >> Are you ready? >
The prediction of runout business is extremely hard. All of these predictions are based on the basic premise that what happened yesterday will most likely happen tomorrow. And in a world of very large populations this is highly likely - the larger the population its often the case that the smaller the impact of individual variations in behaviour. That means that once you get a very large population you'd expect a relatively low level of uncertainty in trend-based predictive models. But the world of addresses is not so well behaved. For some years now we've seen the address world bifurcate into a small number of very large actors and a large number of much smaller actors. In the address world it was observed that less than 1% (its closer to around 0.5%) individual allocations account for more than half of the number of allocated addresses. This becomes a problem in the predictive models, as the dominant factor in address consumption is now the actions of some 20 or so very large entities. If they all fronted at the registry's front doors and asked for a three month allocation, and do so again in 90 days, and so on, then its pretty obvious that ARIN's remaining 40M addresses would not last more than one or two iterations of this cycle. But what has been apparent in the ARIN region since the IANA runout of February 2011 has not been panic, but restraint. If you look at the run-down' of the address pool in ARIN over time (http://www.potaroo.net/tools/ipv4/arin-pool.png), you could certainly make the case that there was a pronounced run on address resources in ARIN in the last quarter of 2010, but it all changed in 2011. The ensuing 14 months following IANA runout, through 2011 and early 2012, saw a pronounced change in the region, and ARIN's address consumption in that period slowed down to a consumption rate that got as low as 1M addresses per month. This coincided in a change in the address allocation policy to reduce the time horizon of "demonstrated need" from 12 months to 3 months, but that factor alone would not account for the entirety of this slow down in the address consumption rates over this 14 month period. Following a single largish allocation in early 2012 we've seen the ARIN address consumption rate increase somewhat, and the average rate of address consumption is currently around 2M addresses per month. If this rate of address consumption continues, the ARIN will reach its last /8 in early 2014, and if this rate persists, then the registry will exhaust its pool around the end of that year, or early 2015. But given the uncertainty factors here as they relate to the distribution of large and small consumers in this area and changing sentiment about whether or not panic is a factor in address demands, I'd have to comment that the uncertainty factor of any prediction is high. Its quite plausible that exhaustion could occur some 6 - 9 months earlier than these dates. However, personally I find it a little hard to place a high probability on Tony's projected exhaustion date of August this year. I also have to qualify that by noting that while I think that a runout of the remaining 40 M addresses within 4 months is improbable, its by no means impossible. If we saw a re-run of the address consumption rates that ARIN experienced in 2010, then it's not outside the bounds of plausibility that ARIN will be handing out its last address later this year. thanks, Geoff
