Effect of SS7 disruptions on dialup Internet access

[Sean Donelan <sean () donelan com>]

A few questions.  I'm completing my paper on the effect of fiber cuts
on the Internet, and I'm looking for a few data sources or SWAGs.

How much Internet dialup is done via access banks connected to CLEC
lines versus to Bell/ILEC lines?  

What percentage of the CLEC Internet dialup ports depend on a third-party
(i.e. Illuminet) SS7 data channel to complete the call between the
typical residential/business user on an ILEC line and the ISP on a
CLEC line?

My theory is because many of the ISP ports have migrated off the ILEC
networks onto CLECs they are impacted by a SS7 failure more than the
traditional call traffic.  SS7 failures are very rare, but the two I know
about disrupted dialup ISP access across huge geographic regions.