Have you tried using CHAP instead of PAP to see if it makes a difference. However, I think that your problem is caused by the wrong ATM encapsulation. Login into the modem and change the ATM enc from VC-MUX to LLC or vice versa and see if it makes a difference. Your ISP's instructions would help you choosing the right parameters and thereafter you should be able to receive PPPoE responses when you debug your Netvanta during authentication.
Hope this helps.
Good afternoon Mick,
Thank you for the reply. I had tried both CHAP and PAP, but knew and confirmed with Bell that it has to be PAP. The encapsulation is not something I have tried though so I will keep note of it, however since I needed to get the client up and running as quickly as possible since their phone lines are VoIP, I set the Bell modem up as a router with IP address reservation for the 3120 and added it to the DMZ. So far this has all worked as it should and I can't bring them down to try your suggestion.
When I go back on site next week, if I am able to bring down the Internet without disrupting their work I will try it.