A roaming network with two AirPort Extremes connected to a switch?

If you saw "extend using Ethernet" during the setup, then the AirPort Express is set up correctly.

Once the Express is set up.....if you are using AirPort Utility on the iPad......

Tap on AirPort Utility

Tap on the AirPort Express on the network layout illustration

Tap Edit in the upper right hand corner

Tap Network

The setting for WiFi Mode should be "Create a wireless network".

This is the correct setting. Remember that all AirPorts are set up the same in a roaming network to "create a wireless network"

The Express should NOT be set up to "extend a wireless network" That setting is used only if the Express is going to connect to the AirPort Extreme using wireless.

You are using Ethernet to connect to the Express, so the correct setting is "Create a wireless network"

Just trust the AirPort Utility setup wizard. It might indicate that it is setting up the Express to "extend using Ethernet" during the setup process......but it really will be setting up the Express to "create a wireless network" if the Ethernet switch and Ethernet cabling are working correctly.

.....have another AirPort in another room connected to the same Ethernet switch as the first AE, with the same SSID and password.

Piece of cake. The AirPort Utility setup wizard will practically do everything for you automatically in a minute or two. Apple uses the terminology of "extend using Ethernet" to mean "roaming".

If you need a few more tips, tell us whether you will be using a Mac or an iPhone / iPad to set things up.

.......But while a mesh seems to work very well for most users, in principle I don't like the idea of extending the network wirelessly when I have the technical option to setup a wired connection to another base station.

The better mesh systems like Netgear Orbi, Eero, etc all allow Ethernet connections between the WiFi access points. If you are considering a mesh system, check the system specs to make sure that the system will support an Ethernet "backbone".

Assuming you have the most recent version of the AirPort Express.......the model with two Ethernet ports.......OR......you have the previous version Model A1264......

You must first reset the AirPort Express back to default settings and then set it up again so that the setup "wizard" will apply the correct settings automatically.

Perform a Hard Reset on the AirPort Express by holding in the reset button on the device for 7-8 seconds. Then, release the reset button and allow a full minute for the Express to restart to a slow, blinking amber light status.

Make sure that the Ethernet cable from your Ethernet switch connects to the WAN "O" port on the AirPort Express....before....you set up the Express again. If your AirPort Express model has only one Ethernet port, then use that port. Here, I assume that you have previously tested the Ethernet cable to make sure that it is working correctly.

Click on the WiFi menu at the top of your Mac's screen and look for a listing of New AirPort Base Station

Just below that listing, click directly on AirPort Express

When you click on AirPort Express, that will open up the setup "wizard". It will take a few seconds to analyze the network and then present a screen that looks similar to the illustration below except that you will see your devices displayed.

Type in a short simple name that you want to call the AirPort Express

Click Next

Watch the next screen very carefully to make sure that the AirPort Express is being set up to "extend using Ethernet". This will confirm that the setup wizard has picked up the Ethernet connection to the AirPort Express and it will apply the correct settings for a roaming network.........which is the same thing as extend using Ethernet.

If you do not see "extend using Ethernet" during the setup, then there is a problem somewhere either with the switch or Ethernet cabling. If this occurs, the Express will be set up incorrectly.

When you see the message of Setup Complete, click Done. If the Ethernet cabling is working correctly, then so too will the AirPort Express be working correctly.

Set up a new AirPort Extreme exactly the same way, except that you will see an AirPort Extreme under the listing of New AirPort Base Station.

Although it will work, you would not want to connect the second AirPort to the first AirPort unless there were no other options.

Why? Let's say the first AirPort has a problem. If it does, the second AirPort will have a problem as well.....but....you won't know which AirPort really has the real problem unless you troubleshoot both AirPorts.

When both AirPorts are connected to a switch, the first AirPort might have a problem, but the second will not. Makes troubleshooting much quicker.