Upgrading from RBR20 to RBK852

[Jmccann6]

I'm going to be upgrading from RBR20 to RBK852.  I have a 1 gig connection and 50 or so devices on the network and have outgrown the RBR20.

I have U-verse.  What if any changes need to be made on the modem?

[plemans]

If you're already got it setup properly for the RBR20, there shouldn't be any changes. 

[FURRYe38]

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too? Built in router here by chance? If so,

This would be a double NAT (two router) condition which isn't recommended. https://kb.netgear.com/30186/What-is-Double-NAT
https://kb.netgear.com/30187/How-to-fix-issues-with-Double-NAT
Couple of options,
1. Configure the modem for transparent bridge or modem only mode. Then use the Orbi router in router mode. You'll need to contact the ISP for help and information in regards to the modem being bridged correctly.
2. If you can't bridge the modem, disable ALL wifi radios on the modem, configure the modems DMZ/ExposedHost or IP Pass-Through for the IP address the Orbi router gets from the modem. Then you can use the Orbi router in Router mode.
3. Or disable all wifi radios on the modem and connect the Orbi router to the modem, configure AP mode on the Orbi router. https://kb.netgear.com/31218/How-do-I-configure-my-Orbi-router-to-act-as-an-access-point and https://www.youtube.com/watch?v=H7LOcJ8GdDo&app=desktop