AirPort Express as Ethernet Bridge
18 Jul 2010 17:29 Filed in: Mac Hardware
This post describes how to use an Apple AirPort Extreme Base Station together with an Apple AirPort Express to solve a single problem: create wired Ethernet connections to devices that are nowhere near your wired network. There are, of course, other ways to do this such as using your existing home wiring or actually running Ethernet through your house. There are advantages to these methods, but—for now—the Tired Donkey is going to tell you how to use AirPort devices to accomplish this little trick.
Please allow the Tired Donkey to begin by describing the problem he is talking about. Let us say that your DSL or cable modem is in your den. To create an 802.11n (WiFi) network in your house, you have run an
Ethernet cable from the modem to an AirPort Extreme Base Station and configured the base station properly (meaning with appropriate password protection). Perhaps you have a computer or a printer also attached to the base station directly with Ethernet cabling. But now you want to create a wired Ethernet connection to several devices (a Mac Mini, your TiVo, an old Windows computer with no WiFi capability, whatever) on the other side of the house. What to do?
One solution is to use an AirPort Express as an Ethernet bridge. What does this mean? If you search the web for the phrase “AirPort Express as Ethernet bridge,” you will find vast fields of confusion out there involving acronyms like WDS and ProxySTA. The Tired Donkey, as is his wont, will cut through the crap for you.
First, a little vocabulary. “WDS” stands for Wireless Distribution System, and it is the protocol that lets an AirPort Express extend the reach of an AirPort Extreme Base Station by—in effect—picking up its signal and rebroadcasting it. You would use this in a
situation where your WiFi network reaches to your living room, but you need it to go just a little farther so you can work on your deck while smoking a cigar. What you would do in this situation is place an AirPort Express close to the limit of your existing WiFi network and set it up to extend the range of that network. Now you have WiFi on your deck, but with one drawback: the WDS network has to use bandwidth to maintain itself, so available bandwidth to all computers hooked to that network is degraded significantly. If you have a screaming-fast internet connection, it probably won’t matter, but if you have a minimal DSL connection, it’s not a good idea to extend your network in this way. But the Tired Donkey digresses, both visually and thematically.
Now a little more vocabulary. “ProxySTA” simply stands for Proxy Station, and when you set up your Airport Express in ProxySTA mode, it does two things differently than when it is acting as a repeater: (1) it will communicate only with the base the station (it will not rebroadcast to other computers), and (2) its Ethernet port becomes active as if it were an Ethernet port on the base station itself. And ProxySTA has a bandwidth advantage over a repeated WDS network because there is no overhead in the pure, two-way communications between the base station and the AirPort Express.
To make this point even more clear, please allow the Tired Donkey to give you an example. Let us say that you want to use your 6 mbps DSL service to provide a broadband connection to a Roku device attached to your television. But the Roku is in a
cabinet and doesn’t get a consistent enough WiFi signal to allow you to stream HD content from NetFlix. You have two choices: set up a WDS network and repeat your network wirelessly using an AirPort Express. This will work fine, but the bandwidth you deliver to your Roku will be cut in half. If, instead, you set up the AirPort Express in ProxySTA mode and connect the Roku to the AirPort Express with an Ethernet cable, you will get the full 6 mbps delivered to the Roku. Cool.
So how do you do this. Here are the instructions, step-by-step, beginning with the assumption that you have already established a working 802.11n WiFi network with an AirPort Extreme Base Station and plugged in your AirPort Express in a location that will allow it to (1) get a signal from the base station and (2) reach the devices you want to attach to it with an Ethernet cable.
1. Start your AirPort Utility located in your Applications/Utilities folder and make sure both the base station and the AirPort Express show up. Select the base station and click the “Manual Setup” button.
2. Select the “Wireless” tab at the top of the screen and make sure the “Allow this network to be extended” box is checked.
3. Select the “Access Control” tab at the top of the screen and make sure the “Mac Address Access Control” drop-down box says “Not Enabled.”
4. If you have made any changes, click Update in the lower right corner of the window.
5. Wait for the update to conclude.
6. Now select the AirPort Express on the left side of the window and click the “Manual Setup” button.
7. Select the “Wireless” tab at the top of the screen. In the drop-down box beside “Wireless Mode,” select “Join a wireless network.” In the drop-down box beside “Wireless Network Name,” select the network name you assigned to the base station. Make sure the “Allow Ethernet clients” box is checked.
8. Click “Update” in the lower right corner and wait for the AirPort Express to update itself.
That’s it. You are done. Connect an Ethernet cable to the AirPort Express and connect that to your device. Or add a hub and connect multiple devices. Enjoy.
A NOTE ON COMMENTS: In September 2012, the commenting system the Tired Donkey had been using was discontinued, and much of the value in this post (plus some interesting Beastie Boys trivia) resides in these comments. To preserve that information, the Tired Donkey preserved the comments. You can access them here. The new commenting system will work just fine going forward.