Optimizing Google Mesh WiFi with ATT Fiber BGW320-500

> using a the same SSID/PWD on the fiber modem and Mesh units

That doesn't sound good. The mesh technologies are not interoperable. Did you at least try turning off the radios on the fiber unit?

Did you set the gateway to pass through mode to allow the mesh router to handle all of the routing and WiFi duties? 

I use the Netgear Orbi mesh system. The primary router is downstairs and the two satellites are upstairs and hard wired back to the router with solid copper core, UTP CAT-6 cable (non-CCS/CCA and not CAT-6 patch cable). Speeds and coverage are excellent throughout our 3500 sq.ft. home and property (1/2 acre). However, I do not use AT&T as my ISP so am free to use my own modem. The router's SSID/pw is different from the Guest Network (which has its own SSID/pw) and the admin setup page for the router. 

Thanks for the responses. Having thought on it it seems like passthrough is the right setting but it has three options. Any suggestions on which one to use?

it seems that when connected to the fiber modem I can’t load most webpages. 

If you are going to connect another router to the gateway, you need to basically "disable" the router functions of the gateway and allow the connected router to handle all of the routing duties and WiFi. You can still use the ethernet ports on the gateway for wired connections. Being as the AT&T gateways don't offer a Bridge Mode, your only other choice is set the gateway in pass through mode to avoid a double NAT, or set the mesh as AP's. I don't use AT&T as my ISP so someone else will have to jump in and give you the specifics and how-to's on configuring the gateway for pass through.

Thanks OTTO, I am going to push ATT a little on this. I am not crazy about having to become a network engineer to use Fiber. My previous provider (XFinity) provided one modem and I bought one pod. That supplied the whole house with no acrobatics on my part. I now have LAN connecting two Google Mesh units and that is not smooth and two others connecting via WAN and seem to have weaker WiFi coverage.

@RonHolmes770  I have Xfinity now and would never use their equipment. So I use my own modem and the Orbi AX4200 Mesh WiFi with two hard wired satellites. With the AT&T gateways you either use pass-through mode (bridge is not available) or you set your satellites as AP's.