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Is it possible to use an AirPort Extreme to extend an existing WLAN while also using the USB/Ethernet ports?

Why I need it: Internet access and HiFi (AirPlay) are currently wired to an AirPort Express in the living room. Now, I want to extend the existing network by a printer and a shared hard disk in another room without having a wire between the two rooms. This other room doesn't have direct internet access, that's why the base station needs to be in the living room.

I searched the internet for hours and even asked an authorized apple reseller, but no one could definitely tell me if the Extreme is able to extend a network while having USB devices attached. I know the AirPort Express cannot do both at the same time, so my hope is that the Extreme can.

Any answer to the specific question, or other ideas to realize this setup would be highly appreciated.

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1 Answer 1

up vote 3 down vote accepted

All 802.11n AirPort base stations (by this I mean Extremes, Expresses, and Time Capsules) can share their USB ports while extending the network from any other Apple AirPort base station. Note that Expresses only support USB printer sharing (not USB hard drives). Extremes and Time Capsules support sharing both USB printers and USB hard drives.

Whoever told you AirPort Express can't do both at the same time, told you wrong.

The full story is that there are basically 4 different ways that different models of base stations can wirelessly join/extend other networks:

Legacy WDS mode

This mode first shipped with the 802.11g AirPort Extreme (early 2003 to early 2007) and AirPort Express (mid 2004 to early 2008). It was based on standard 802.11 WDS mode, but standard 802.11 WDS mode is notoriously under-specified, so Apple never tried to guarantee that it would interoperate with anyone else's products, only Apple's. Even Apple to Apple, it was always a bit fiddly and has since been deprecated, although there are ways to get all the later (802.11n) base stations to use this mode if you really know what you're doing.

This mode supports:

  • Sharing USB printers (and hard drives on models that support it)
  • Bridging Ethernet clients in
  • Extending the network wirelessly as well (that is, simultaneously acting as a WDS bridge and an AP).
  • AirPlay/AirTunes output on AirPort Expresses.

This mode is supported on:

  • AirPort Extreme 802.11g (early 2003 to early 2007)
  • AirPort Express 802.11g (mid 2004 to early 2008)
  • Deprecated, but supported on all 802.11n AirPort base stations (early 2007 - present)

Modern "Dynamic" WDS (dWDS) mode, a.k.a. "Extend"

I believe this mode first shipped with the 802.11n AirPort Extreme (early 2007 to mid 2007). It uses an Apple-proprietary scheme to fix some of the flaws that made legacy, standards-based WDS mode too fiddly.

This mode supports:

  • Sharing USB printers (and hard drives on models that support it)
  • Bridging Ethernet clients in
  • Extending the network wirelessly as well (that is, simultaneously acting as a dWDS bridge and an AP).
  • AirPlay/AirTunes output on AirPort Expresses.

This mode is supported on:

  • All 802.11n AirPort base stations (early 2007 - present)

Wireless client (STA) mode, a.k.a. "Join"

This mode first shipped with the 802.11g AirPort Express (mid 2004 to early 2008). This was so that if you just wanted your AirPort Express to be a wireless audio device (or perhaps just a wireless USB print server) and wanted it to join a pre-exsiting non-Apple Wi-Fi network you had, you could do that.

This mode supports:

  • Sharing USB printers (and hard drives on models that support it)
  • AirPlay/AirTunes output on AirPort Expresses.

This mode is supported on:

  • AirPort Express 802.11g
  • Hidden, but supported on all 802.11n AirPort base stations

"Proxy STA" Wireless client mode, a.k.a. "Join w/ 'allow Ethernet clients'"

I believe this mode first shipped with the 802.11n AirPort Express (early 2008 to present). You'd use this for the same reasons as normal STA mode, with the additional ability to bridge wired Ethernet devices onto the network.

Because the 802.11 spec does not allow normal wireless clients to transparently bridge traffic, the radio in the AirPort Express has to do extra work in this mode to sort of clone the MAC addresses of any wired Ethernet devices it sees connected to its Ethernet port, and fool the upstream AP into thinking those MAC addresses are all separate wireless clients that have all joined the upstream AP (that is, it has to perform the 802.11 "STA" role on behalf of those non-802.11 devices, thus "Proxy STA").

This mode supports:

  • Bridging Ethernet clients in
  • Sharing USB printers
  • AirPlay/AirTunes output on AirPort Expresses.

This mode is supported on:

  • AirPort Express 802.11g (2004-2008)
  • AirPort Express 802.11n (2008-present)
    (Which is to say "All AirPort Expresses, but not Extremes or Time Capsules)
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Thanks a lot for the exhaustive answer! I got the information about the Express not being able to do both simultaneously from an authorized local Apple reseller... –  schluchc Jun 6 '12 at 10:22
    
Is the third mode (STA or "Join") supported on Airport Extreme. If so it seems very hidden. How do I enable it? –  simon Sep 26 '13 at 7:11
    
@simon I think you had to use the old 5.x AirPort Utility, and you had to Option-click the pop-up menu where you set the wireless mode. I'm pretty sure the new tower-style 802.11ac AirPort Extreme does not support this mode. –  Spiff Sep 26 '13 at 17:27

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