We have been experiencing intermittent/temporary ADSL PPPOA dropouts at a
couple of sites.
Typically the ADSL modem is an Actiontec GT701 although we have also used an
old Wirespeed and a Cisco 1710.

The test to recreate the problem:
Set up a continuing ping to a couple of remote sites.
Start a large file ftp transfer OUT of the local site. i.e. an "upload".
(Outgoing emails with larger attachments seem to cause the problem during
normal operations).

With the ftp transfer going we see a few ping dropouts and then a total
The modem drops the PPPOA connection when this happens.
The problem solves itself after 20, 30 or 40 seconds - depending on the
particular configuration of modem, etc. and this interruption time will be
rather constant from outage to outage.

This happened at one site in July and we made it better / acceptable by
changing the modem from PPPOE to PPPOA and assigning a public IP address to
the modem.

Then it started happening a couple of weeks ago at another site about 50
miles away.
The telco and the ISP are the same at both sites and things become common at
some point before or when reaching the ISP equipment.

I have good contact / communication with the ISP and only third-hand via the
ISP with the telco.
We are all scratching our heads as to what must be happening and what we
might do about it.

Rule out all of our office site equipment.
I can connect a bare laptop directly to the modem and recreate the problem.

Any suggestions to point toward what to look for?