Poor performance when using WDS with a Senao NL-3054CB3 802.11g repeater

Josh Green josh at resonance.org
Sat Mar 5 19:18:01 EST 2005


On Fri, 2005-03-04 at 20:58 -0800, Jouni Malinen wrote:
> On Fri, Mar 04, 2005 at 06:42:36PM -0800, Josh Green wrote:
> 
> > Now I'd like to add a Senao NL-3054CB3 802.11g repeater to extend the
> > coverage of my Linux access point.  I configure it for WDS putting in
> > the MAC of my embedded Linux system.  Then I add a WDS link to the
> > hostap driver with the MAC of the Senao repeater.  The link works, but
> > if I do a file copy I get about 40KBytes per second!
> > 
> > Any ideas why I'm getting such poor performance with WDS?
> 
> I would suggest using a wireless sniffer to look at this; preferably one
> that is able to receive IEEE 802.11g frames. WDS links do not usually
> use any kind of association, so it is possible that the IEEE 802.11g
> device believes that the other end is capable of receiving IEEE 802.11g
> frames..
> 
> Another test would be to run a unidirectional (e.g., UDP stream)
> throughput test in both directions. The IEEE 802.11b to the IEEE 802.11g
> direction should get much better results if the IEEE 802.11g device is
> indeed using OFDM rates.
> 

Thank you for the responses.  For some reason things are working much
better now through the repeater (400Kbytes/s upload speeds, 160Kbytes/s
download).  I changed the wireless channel and messed with the
configuration on the 802.11g repeater (although I think most settings
ended up being the same).  This seems semi-adequate for now, but I'm not
quite sure what ended up resolving the issue or if it will return.  I'm
also still curious if these are typical speeds that others have
experienced with repeaters in a mixed b/g environment.

One issue I kept running into when trying to test this stuff, is that I
found it really hard to get my laptop (using hostap) to associate to a
specific AP.  It seems that once it gets connected I end up having to
reboot the AP it is connected to in order to force it to use the other.
Doing a "iwconfig wlan0 AP <mac of AP>" seems to do nothing.  Anyone
else seen this problem?  Thanks again!
	Josh Green





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