From 802.11 Authentication to (Re)Association Response - timings.

Ajeet Nankani fromkth+hostap at fastmail.fm
Tue Feb 15 08:06:09 EST 2005


Hello Vatn,


On Tue, 15 Feb 2005 12:42:52 +0100 (CET), vatn at imit.kth.se said:
> Hi Ajeet,
> 
> Ajeet Nankani said:
> > Last week i did some experiments and found out that from the
> > Authentication request from STA to (Re)Association response from AP it
> > takes around 150ms to 200ms which is quite high, as it should be around
> > anywhere between 5 to 20ms. Also note that these timings does not
> > include any of scanning timings.
> >
> > I have 1.8.0 firmware
> > I used HostAP 0.3.5 build
> > I experimented separately with both, kernel level 802.11 management and
> > with hostapd daemon 802.11 management.
> > It was total open-authentication, no WEP, no WPA.
> > There are not any other APs/STAs in vicinity.
> > I used two APs(Channel 1 and 6), to be able to do handoff.
> >
> > What could be wrong in my setup?
> >
> > Anyone else observed the same or much less timings than these ones?
> 
> I have documented similar tests, but with older hostap driver and
> firmware in a report "An experimental study of IEEE 802.11b handover
> performance and its effect on voice traffic", see
> http://www.it.kth.se/~vatn/research/handover-perf.pdf
> See also Velayos and Karlsson, "Techniques to Reduce IEEE 802.11b MAC
> Layer Handover Time", who use HostAP at the AP side.
> http://www.it.kth.se/~hvelayos/papers/TRITA-IMIT-LCN%20R%2003-02%20Handover%20in%20IEEE%20802.pdf
> 
> Both papers show "execution delays" below 10 ms (1-7 ms).

Yeah, i have already gone through the above and many other research
papers and articles about handoff process and measurements, the latest
being from the guys at Maryland University.

But i could not find what is the problem in my setup, should i downgrade
my firmware and see if it helps?? or something else??

Best Regards.

-ajeet





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