If you want to use a TP-Link 
Deco with CenturyLink 
Gigabit fiber, here is how I made it work.
The CenturyLink supplied ZyXEL C3000Z seemed rather decent, but I wanted 
to directly connect to my TP-Link mesh to minimize hardware power demands 
and router hops.
- Call or Chat with your friendly installer, or contact online the support staff to get the PPOE password. The username can be gleamed from the supplied modem documentation.
 - Go into the TP-Link app and setup the internet connection of the main AP to More -> Advanced -> IPv4 and use the configuration for CenturyLink Fiber.
 - Setup the IPv4 with The PPoE Username and Password.
 - Have the IPv6 use the same login as the IPv4
 - Enjoy! </ol>