Building a WDS Bridge with Consumer Grade WLAN APs
Small AP is small – and has a built-in antenna, too. I got two of these (for 19,90€ per piece – not A-link list price…) and set up a bridge so I could relocate my noisy Xen box from living room to kitchen to keep the box running 24/7 and sleep. (Turns out that in the end even this didn't help because the box remained loud enough to disturb sleep no matter what settings were selected in BIOS thermal management.) Initially it looked like the bridge worked just fine, except my testing revealed that the transmission speed was nowhere near the advertised "IEEE 802.11n (draft 2.0) / 150Mb":
XenCenter.iso 100% 44MB 1.5MB/s 00:29After trying different cryptos from WPA2 to plain text and fiddling with various other settings I came to the conclusion that the slow speed was a feature of the device. Anyway, this was not really any kind of concern as I was more interested in latency, which was low enough (a few milliseconds). Put all this together and my opinion is that it's good enough for an access point that is about the size of a deck of cards and costs twenty euros. What did turn out to be a problem is that at times the AP's would somehow manage get a broadcast storm going on, which of course took the wired network down with it very quickly. I wasn't really able to get to the root of this but from what I observed I can tell that the broadcast storm would happen even when one AP was connected to the primary wired segment and the AP at the other end was just "floating" there, with nothing connected to its' Ethernet ports. Also, while after enabling STP in the devices I could, using
tcpdump, observe the STP config packets doing their thing and reconfiguring after for example dropping and then reconnecting either end of the bridge, this (STP) did nothing to prevent the broadcast storm from happening. I should also note for the record that I was using the "WDS", not "AP+WDS" mode.
Verdict: the devices just aren't suitable for this application, i.e. they are buggy and do not fully work as advertised but given their relatively compact size and ability to function as clients on a WLAN, I'll keep these.Categorised as: experimental