Wireless network optimization in a long/wide single family brick house

Question

I live in a rancher-style house in the US (for those not in the US, just a single level home that is usually a bit wider than it is deep). There is an extension on the house that extends past the original brick wall that we spend most of our time in. My office is on the complete opposite side of the house, and that is where the coaxial cable comes in the house to connect to the Verizon FiOS router.

With just using that router, the signal in our extension is mostly unusable due to the brick wall. Because we have some network cable run, I now have an Airport Extreme set up in the extension.

If I turn off wireless on the Verizon router, the airport Extreme will reach the other side, but doesn't work. Same if I disable the airport, you cant get wireless in the extension.

I feel that having both of these running does cause interference though. For example, sometimes devices won't loose their connection to the other base station without disabling and then re-enabling WIFI. Other issues are sometimes slowness or odd coverage in other areas (for example, outside the house, the wireless isn't as good as it was with one).

Both routers are using the same SSID and should be on separate channels. Both are running a 2.4ghz g network, and the airport extreme also is running a 5ghz network too.

What would be the best setup with either

1. using the two routers or
2. working with WIFI in a brick house?

UPDATE - Adding some notes thanks to Spiff's answer

1. NAT/DHCP is handled by the Verizon router, those services are off on the Airport Extreme
2. Devices are on separate channels that are spread out
3. Both use the same SSID and WPA PSK
4. Airport is setup using the default - 2.4 b/g/n, and 5 a/n .

Also, changing the title to better reflect the real question - how do I get this to work the best way? I don't mind not using Verizon's wifi router if I can set up the Airport Extreme to work better - ie not even using the 5ghz band, etc.

Answer 1

Note that in 2.4GHz, the channels overlap. So if you have one device on channel 1 and the other on channel 2, you're right that they're interfering. Channels 1, 6, and 11 are far enough apart from each other that they don't overlap with each other, so make sure you're using channels that are "5 channels apart" like that to avoid overlap.

If you have both devices using the same SSID, make sure they're using the same security mode and wireless password as well. Also note that client devices can optimize their roaming/scanning algorithms if the SSID is being broadcast, as opposed to a hidden/closed/non-broadcast SSID.

For best range and performance, leave the AirPort Extreme in its default radio mode of doing b/g/n in 2.4GHz and a/n in 5GHz. I've seen people turn off the legacy a/b/g protocols because they didn't realize that even N clients fall back to those rates when they need greater range, and I've seen other people turn off N in the 2.4GHz band really for no good reason at all, not realizing that their dual-band N clients can get a little better range by switching from 5GHz to 2.4GHz at distance.

Edited to add: Since your Verizon FiOS box has to be at the head of your network (since it's the only device with the MoCA coax port that connects to your FiOS demarc), let it do NAT and DHCP for your whole network, and make sure you turn those services OFF on your AirPort Extreme (i.e. put the AirPort Extreme in "Bridge mode").

Answer 2

You should only use one router, but the other is OK to use the other at the same time as an access point. The SSID that you use is irrelevant to how well it works, but using different SSIDs may make it easier to know which one you are connecting to so you choose the one on the right side of the house. Many materials are bad for WiFi, and brick is amongst the them. Your solution of running a cable and adding a second access point is probably the easiest and the most effective of options.