Extending a non apple wifi network

You might think that the correct setup would be to "extend a wireless network", but that setting is used only if your "main" router is another Apple AirPort product.......and......the extending AirPort connects using a wireless connection......(not Ethernet).

Your "main" router is not an Apple product.....and.....the extending AirPort is not compatible for a wireless only connection with a 3rd party router. So, the only option that you have is to go with is the configuration that the set up "wizard" suggests for you automatically. It is the only option that you have that will work correctly.

If you are looking at the "join" option, when an AirPort router "joins" a network......it cannot and does not extend the network. The AirPort Extreme cannot "join" a 3rd party network anyway, so no reason to even try.

The "join" setting is used almost exclusively if you have an AirPort Express and you want it to join a network to use with AirPlay. The Express is the only Apple router that can "join" a 3rd party network.

When you have two routers that connect together using Ethernet and both routers produce a WiFi signal that uses the same wireless network name and password......this type of network is technically called a "roaming network".

Save yourself some time and frustration and go with the setup that AirPort Utility suggests. It is the correct setup for you to use.

Now, on a completely different topic.......my neighbor recently installed one of the new "mesh" WiFi systems. His system has 3 "access points" or 3 routers and guess what.........his WiFi network shows up 3 times using a WiFi diagnostic check.

My issue is that I can't successfully get through the settings changes on the AE to extend a network.

That would be because you need to first need to perform a Factory Default Reset or a Hard Reset on the AE......before......it can be configured to work with your Xfinity router.

The Hard Reset is much easier for most users, since you almost need to have 3 hands to perform a Factory Default Reset. To perform the Hard Reset on the AE, power it up and let it run for a minute, then hold in the reset button on the back of the AE for 7-8 seconds and release. The AE will restart to a slow blinking amber light status after about a minute.

Then connect an Ethernet cable from one of the Ethernet ports on the Xfinity router.....there are likely 4 out them, choose any one that you want.....to the "O" Ethernet port on the AE. Note that this must be a permanent connection.

Open AirPort Utility on your Mac

Click on Other WiFi Devices

Click on the AirPort router

That will start up the AirPort Utility setup "wizard". The wizard will take a few seconds to analyze the connections and then display a screen that will look similar to the example below except that you will see your AE pictured.

Network Name.......Type in the exact same name that the Xfinity router is using for the WiFi network

Base Station Name.....Type in a short name that you want to call the AE

Password......Type in the exact same WiFi password that the Xfinity router is using

Verify.....Type in the same password again to confirm

Click Next, and the setup wizard will configure the AE with the correct settings

When you see the message of Setup Complete, click Done......and you are done

Should be a nice bright green light on the AE at this point

You are all set now

Different 3rd party routers behave differently with Apple routers, so you might see multiple networks with the same name or only one network.

You have the correct setup above to extend the network with a 3rd party router. In fact, it is the only way to set up the AirPort correctly.

For what it's worth, I have 3 Apple routers here all wired together using Ethernet. If I use a utility like WiF Explorer or WiFi Scanner to check the network, the same network appears 3 times.