nanog mailing list archives

Re: CAIDA's AS-rank project


From: Richard Barnes <richard.barnes () gmail com>
Date: Fri, 7 Sep 2012 18:51:34 -0400

No IPv6?

On Thu, Sep 6, 2012 at 6:46 PM, Matthew Luckie <mjl () caida org> wrote:
Hello,

We have been working on refreshing the data and algorithms behind CAIDA's
as-rank project.  We have published AS-relationships and AS-rankings
computed for June 2012.  We are currently seeking further validation of our
rankings and relationship inferences.

http://as-rank.caida.org/

The core of the algorithm is the inference of business relationships. Over
the past two years we have received a significant amount of ground truth
from operators through the corrections facility provided within AS-rank: in
particular we obtained >1200 p2p relationships as a result of our previous
algorithm that assigned many more customer/provider (c2p) relationships than
ASes had in reality.  Our intuition is that network owners are a lot more
concerned when we infer a provider relationship that is actually a peer
relationship, but are less motivated to validate other inferences.

We have validated our algorithm against available ground truth and find our
relationship inferences have a 99.1% positive predictive value (PPV) for c2p
and 94.7% for p2p for the validation data we have available. Because
customer cone computation depends on the accuracy of our c2p inferences, we
are reasonably confident in our computed rankings.

We are now soliciting further feedback in any shape and form offered. The
as-rank website provides the ability for operators to submit corrections
through the right-most "corrections" button on an individual ASes
information page, and relationships ground-truth is solicited through that
channel, if at all possible.  Other feedback, on or off-list, would also be
appreciated.

If you are curious as to why a particular relationship was inferred, please
get in contact with me.  Some ASes have advised of a particular business
relationship in the past, but when I drill down into the data it turns out
they have a misconfiguration and are leaking routes to a peer.  At a
minimum, this might be a useful sanity check for some ASes who may be
providing free transit without realising it.  In the future, we plan to
annotate each relationship with examples as to why it was inferred the way
it was, but we have not yet got that far yet.

Thanks,

Matthew Luckie
CAIDA



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