Determining what AS' are being announced

[Jason Lixfeld <jlixfeld () team look ca>]

I'm doing traffic analysis to try and determine the amount of traffic I'm
sending to or through a particular AS.  I'm wondering if there is a
documented matrix or a utility that can determine what AS' a particular AS
is announcing.  Once a reasonably accurate as-path has been generated, I can
tell flowscan to grab statistics for all the AS' in the path, but until I
know that as-path, I can only get stats for say PSI, but not for it's
customers.

Thanx in advance.