said by Kevin Bryan:
so would I log in via PPPoE on my router? or in this hypothetical scenario would I keep my router in access point only mode (no NAT) like it is now ?
No, you would not use PPPoE on your router
, the (new/DSL replacement) AT&T supplied router/modem will handle the authentication with DSL line. There is no true bridge mode on the AT&T 3600HGV like there was with previous AT&T DSL modems. These new router/modems are VDSL. You configure your router, connected via it's WAN port to the 3600HGV LAN port, to receive a DHCP address from the AT&T router then put your router into the AT&T router/modem's DMZplus zone. The links above, in particular this link: »forums.att.com/t5/Residential-Ga···/2707013
, in my previous post explain how to configure a router to work in DMZplus mode with the AT&T supplied Uverse router.
Here is another link for those who use Tomato firmware based routers. Connecting a Tomato Based Router to an AT&T U-Verse 2wire 3600HGV: »rockydog.homedns.org/Uverse.php
The simplest way to connect another router behind the 3600HGV is to disable the second router's DHCP server and connect the the 3600HGV to the second router by the wired LAN ports, NOT the second router's WAN port. Note with DD-WRT and Tomato you can reconfigure the WAN port to act as a LAN port. I currently have my Belkin F7D7301 wireless N router, loaded with TomatoUSB, configured this way to allow for the 3600HGV to handle the B/G wireless clients and the Belkin router handles the N wireless clients.