[Cu-wireless] major interference

Wed Aug 20 10:08:00 CDT 2003

I think it will probably be easier for the CUW network to move ourselves
from channel 11 -- I recommend channel 3 since no one seems to be using it
and it's fairly far from both channel 6 and channel 1.  Most off the shelf
hardware defaults to channel 11, so I would expect that we'd constantly
have interference problems popping up on it.  I think if we hard-coded our
software to use channel 3 we'd be able to do a network wide switchover in
just a couple hours.

--Sascha

On Tue, 19 Aug 2003, David Young wrote:

> Below is a worrisome packet capture I took from the node at IMC at
> 11:17pm tonight.
>
> (BTW, the noise levels are totally bogus.)
>
> You can see that there are a handful of non-CUW stations operating. Most
> of them are not a major concern. There is 'cuw' (our node on Green
> Street), TNT (unknown), and SG 11/l-uts (Volo.net at the corner of
> Illinois & Race). I think that Volo will cooperate with us and move from
> channel 11, but nobody has any right to the channel.
>
> What I am concerned about is the -23dBm (!!)  station, which sometimes
> transmits full-throttle to a second station out of IMC's range. In this
> trace, you can only see it acknowledge packets from the other station,
> but there were lots of WEP-encrypted data packets earlier today. The
> signal strength is amazing: I do not usually receive signals that strong
> when I have two radios on the same table. I have asked Peter, and it is
> not Volo. Who could it be?
>
> The first three octets of the MAC address (00:02:6F) identify the radio
> manufacturer as Senao, i.e., not a radio you can buy at Best Buy. So I
> think that it must be a hobbyist or WISP or something.
>
> Is somebody interested in tracking down the source, for curiosity's sake?
>
> *** start capture ***
>
> 10:57:06.388599 2Mb/s -23dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.401520 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.414222 2Mb/s -21dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.419791 2Mb/s -70dBm signal, -73dBm noise BSSID:0:5:5d:5b:6b:c6 DA:ff:ff:ff:ff:ff:ff SA:0:5:5d:5b:6b:c6 Beacon (Get Volo!) [1.0* 2.0* 5.5* 11.0* 22.0 Mbit] ESS CH: 11
> 10:57:06.433213 11Mb/s -61dBm signal, -73dBm noise BSSID:2:6:9e:21:a1:ef DA:ff:ff:ff:ff:ff:ff SA:0:2:6f:1:c7:b1 Beacon (cuw) [1.0* 2.0* 5.5* 11.0* Mbit] IBSS CH: 11
> 10:57:06.439703 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.446007 2Mb/s -71dBm signal, -73dBm noise RA:0:9:5b:4d:d0:c0 Acknowledgment
> 10:57:06.446888 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.460236 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.474181 2Mb/s -24dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.480095 5Mb/s -61dBm signal, -73dBm noise BSSID:0:2:6f:3:fd:b8 DA:ff:ff:ff:ff:ff:ff SA:0:2:6f:3:fd:b8 Beacon (SG 11/l-uts) [1.0* 2.0* 5.5 11.0 Mbit] ESS CH: 11 , PRIVACY
> 10:57:06.490104 2Mb/s -73dBm signal, -73dBm noise BSSID:0:9:5b:4d:d0:c0 DA:ff:ff:ff:ff:ff:ff SA:0:9:5b:4d:d0:c0 Beacon (TNT) [1.0* 2.0* 5.5 11.0 Mbit] ESS CH: 11 , PRIVACY
> 10:57:06.493393 2Mb/s -21dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.507268 2Mb/s -23dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.520394 2Mb/s -21dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.522216 2Mb/s -70dBm signal, -73dBm noise BSSID:0:5:5d:5b:6b:c6 DA:ff:ff:ff:ff:ff:ff SA:0:5:5d:5b:6b:c6 Beacon (Get Volo!) [1.0* 2.0* 5.5* 11.0* 22.0 Mbit] ESS CH: 11
> 10:57:06.534417 2Mb/s -23dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.552446 2Mb/s -72dBm signal, -73dBm noise RA:0:9:5b:4d:d0:c0 Acknowledgment
> 10:57:06.553047 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.553479 2Mb/s -70dBm signal, -73dBm noise RA:0:9:5b:4d:d0:c0 Acknowledgment
> 10:57:06.567531 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.582287 5Mb/s -61dBm signal, -73dBm noise BSSID:0:2:6f:3:fd:b8 DA:ff:ff:ff:ff:ff:ff SA:0:2:6f:3:fd:b8 Beacon (SG 11/l-uts) [1.0* 2.0* 5.5 11.0 Mbit] ESS CH: 11 , PRIVACY
> 10:57:06.585932 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.598250 2Mb/s -25dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.610345 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.624248 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.646368 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.656846 2Mb/s -26dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.668620 2Mb/s -23dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.685099 5Mb/s -61dBm signal, -73dBm noise BSSID:0:2:6f:3:fd:b8 DA:ff:ff:ff:ff:ff:ff SA:0:2:6f:3:fd:b8 Beacon (SG 11/l-uts) [1.0* 2.0* 5.5 11.0 Mbit] ESS CH: 11 , PRIVACY
> 10:57:06.687786 2Mb/s -72dBm signal, -73dBm noise RA:0:9:5b:4d:d0:c0 Acknowledgment
> 10:57:06.688671 2Mb/s -71dBm signal, -73dBm noise RA:0:9:5b:4d:d0:c0 Acknowledgment
> 10:57:06.694876 2Mb/s -73dBm signal, -73dBm noise BSSID:0:9:5b:4d:d0:c0 DA:ff:ff:ff:ff:ff:ff SA:0:9:5b:4d:d0:c0 Beacon (TNT) [1.0* 2.0* 5.5 11.0 Mbit] ESS CH: 11 , PRIVACY
> 10:57:06.696167 2Mb/s -25dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.696252 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.708281 2Mb/s -21dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.743761 2Mb/s -22dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
> 10:57:06.782461 2Mb/s -21dBm signal, -73dBm noise RA:0:2:6f:4:a0:b6 Acknowledgment
>
> Dave
>
>