4 May 2007

IPv4 Address Space Exhaustion

This blog entry on the ICANN site shows some interesting maps of the assigned IPv4 address space and some links to discussions on IPv4 address space exhaustion: ICANN Blog: Blog Archive: Mapping the Internet, one node at a time

I have recently noted to my work colleagues in the TSSG that Geof Houston's (of APNIC) predictions are now converging with Tony Hain's (of Cisco) predictions at around late 2010 - mid 2011 for the last IANA/8 to be allocated, that's less than 1 year divergence. This means that there is broad agreement on this prediction.

Geof Houston's prediction is updated regularly. As of yesterday he predicts no IANA/8 left after 06-Jul-2011.

UPDATE 2007-05-08 Geof's prediction revised to December 2009!

Tony Hain's prediction, published in September 2005 in the Cisco IPv6 protocol Journal, and well worth a read both for the article itself and for the discussion printed at the end of the article. His predictions are summarised in these two statements:

"So this view of the sustained trend in allocation growth rate suggests that the lifetime of the remaining central IPv4 pool is 4 years +/-1." [i.e. Sep 2009 +/-1]


"The various projections in Figures 5 and 6 show different mathematical models applied to the same raw data. Depending on the model chosen, the nonlinear historical trends in Figure 6 covering the last 5- and 10-year data show that the remaining 64 /8s will be allocated somewhere between 2009 and 2016, with no change in policy or demand (though as discussed previously there are already reasons to err toward 5-year based nonlinear models)."

His model graph is updated quarterly.

In fact it is worth quote the concluding few sections of Ton Hain's original article in full as they address a number of other possible issues that may arise:

"Reserved Space
There are occasionally arguments that the 16 /8s reserved in the experimental space could be used. Although this is likely to be possible for some IP stack implementations, for others it is not. At a minimum, some quick tests show that Windows 95 through Windows 2003 Server systems consider that block to be a configuration error and refuse to accept it. The operational ability to restrict the space to a select stack implementation is limited, and the amount of space there does not really help even if deployment and operations were trivial. Assuming the sustained growth trend in allocations continues, by the time the remaining 64 /8s in the IANA pool are finished the rate would be approaching 3 /8 allocations per month, so the entirety of the old Class E space would amount to about 6 months of run rate.

Reclaiming Allocations
Another debate occasionally resurfaces about reclaiming some of the early allocations to further extend the lifetime of IPv4. Hopefully this article has shown that the ROI for that approach is going to be extremely low. Discussions around the Internet community show there is an expectation that it will take several years of substantive negotiation (in multiple court systems around the globe) to retrieve any /8s. Then following that effort and expense, the likelihood of even getting back more than a few /8 blocks is very low. Following the allocation growth trend, after several years of litigation the result is likely to be just a few months of additional resource added to the pool - and possibly not even a whole month. All this assumes IANA does not completely run out before getting any back, because running out would result in pentup demand that could immediately exhaust any returns.

Network Address Translation (NAT) and CIDR did their jobs and bought the 10 years needed to get IPv6 standards and products developed. Now is the time to recognize the end to sustainable growth of the IPv4-based Internet has arrived and that it is time to move on. IPv6 is ready as the successor, so the gating issue is attitude. When CIOs make firm decisions to deploy IPv6, the process is fairly straightforward. Staff will need to be trained, management tools will need to be enhanced, routers and operating systems will need to be updated, and IPv6-enabled versions of applications will need to be deployed. All these steps will take time - in many cases multiple years. The point of this article has been to show that the recent consumption rates of IPv4 will not be sustainable from the central pool beyond this decade, so organizations would be wise to start the process of planning for an IPv6 deployment now. Those who delay may find that the IANA pool for IPv4 has run dry before they have completed their move to IPv6. Although that may not be a problem for most, organizations that need to acquire additional IPv4 space to continue growing during the transition could be out of luck."

So it is clear to me that IPv4 addresses are running out, and IPv6 is the only viable alternative. Whilst the TSSG do engage in "post-IP" research, looking at potential alternatives, there is no question that IPv6 will need to be deployed to meet IPv4 exhaustion, and any post-IP research will require 10-15 years to be ready for deployment, and that's simply too late for IPv4 exhaustion.

This is why I am Director of the Irish National IPv6 Centre and Chair of the Irish IPv6 Task Force and Ireland's representative on the European IPv6 Task Force and the world-wide IPv6 Forum. When we started the Irish National IPv6 Centre in September 2005 there were 64 IANA/8 blocks left, last month this was down to 47. The waiting game is over, it is time to start planning IPv6 deployment today.

Posted by mofoghlu at May 4, 2007 12:42 PM | TrackBack
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