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
ftp.arin.net.
You mean the stats files, which provide delegation date, type,
starting number, length, etc.?
Yes.
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!
Thanks,
TV