North American Network Operators Group

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Re: IPV4 as a Commodity for Profit

  • From: Tom Vest
  • Date: Fri Feb 22 22:19:38 2008

Hi Iljitsch,

Thanks for your response.

On Feb 23, 2008, at 1:38 AM, Iljitsch van Beijnum wrote:

On 22 feb 2008, at 16:41, Tom Vest wrote:

You can download files with all the delegation info from

You mean the stats files, which provide delegation date, type, starting number, length, etc.?


Which one of the published fields is the key field that enables you to identify the common recipient(s) of successive delegations over time?

There is no such field.

I didn't think so. So there is no accurate way to get anything like a sum of IP address per LIR at any point in time, now or in the the past, at least not using publicly available data. Given that impossibility, I still don't see how anyone can make the (increasingly oft repeated) claim that 90% (or any specific share) of address space is now going to some subset of the LIRs... no?

No, simply because large ISPs need lots of addresses, everyone else can make do with just a few.

But in the absence of some other metric for largeness, that sounds like a tautology. Large ISPs are the ones that demand lots of addresses... ergo to demand a lot of addresses is to be large...

You've got a point there. However, I think many of us will be able to judge ISP size from other factors and observe that the correlation by the such determined ISP size and address use is quite high.

I agree that many of us can estimate ISP size even more accurately, by looking at the sum of address space originated by well-known ASes associated with those ISPs. I think many of us will recognize that there may be other, less well-known ASes associated with some of these, and so an accounting of the well-known ones is incomplete, perhaps a lower bound. I agree that some of us can correlate the contents of the routing table over time with the entries in the delegated files, to get very loose inter-temporal (delegation- origination) associations, which have been shaped over time in opaque ways by M&A, multihoming, customer management and traffic engineering engineering practices, etc. However, I still haven't seen anything that enables one to penetrate this fog of largely unknowable commercial and operational details sufficiently to justify the 90% claim -- or any other claim.

If there is some known method for doing this, and hence some defensible way to derive the actual (maybe 90%?) ratio, then I'd still be very interested to hear about it! I think all of the academics who spent several years trying (with mixed results) to come up with algorithms for inferring inter-AS relationships, etc. would be very interested too!