My opinion only:
The Arris is a combined modem/router?
That is to say, what they call "a residential gateway"?
If so, I would set things up like this:
For the moment, remove the AE (Airport Extreme) from the picture.
Run with the Arris only, to get started.
Set up wireless -temporarily- with the Arris.
Can you get connected this way?
If so, then I would do this:
- Connect the AE to one of the Arris' ethernet ports
- Set up the AE by TURNING OFF NAT, and using it in bridge mode
- Choose to create a new wireless network.
Once you have the AE's wireless running, go back to the Arris and TURN OFF its wifi.
Now, the Arris will be the modem (of course), but it will also serve as your router and do NAT.
The AE will be the wifi device (but with NAT turned off so you don't have "double NAT").
Try this and see how your throughput is.
If it's "where it should be", I would run that way and be happy.
I'm of the mind that believes that the "device closest to the internet" should do the NAT and routing. The Arris will do this.
Use the AE to create and maintain your wireless network.
I've used this style setup for a couple of years now (Frontier/Uverse), and it works well, no problems...
