Actiontec offers the following when setting up the WAN side for the GT701D and also I believe for the GT704-WG..
DHCP Static IP “Routed” PPPoE PPPoA RFC 1483 Transport Bridging
Does anyone have an idea what you are actually using when you select DHCP? The last four are pretty obvious but since DHCP is just a way of handing out dynamic IP addresses, it does not indicate what exactly the transport method is.