Security-risk Interferer 'WiFi Inverted' is detected.

[thomas03usmcsf]

Anyone have any solid information on this warning?  I found a few things online, but nothing great.  Thanks.

[Nicolas Darchis]

Actually, spectrally inverted is swapping the I and Q arms of the signal.

   I(n)' = Q(n);

   Q(n)' = I(n);

That just looks like noise to any WIFI chip, other than for Long Preamble 11b.

Inverted: I/Q (in-phase/quadrature) modulation is inverted, compared to the 
802.11 spec

[patoberli]

Do you maybe have more information about this?

I receive that alarm around 10-30 times a day on our campus. WCS treats this alarm with a Severity of Critical and thus I receive the email. But the email does not really contain any details.

Is there a way to troubleshoot this issue on the controllers?

Is there a way to found out which controller raised the alarm?

The alarm usualy goes away after 1-2 minutes.

[patoberli]

Hi (small update)

We also have still quite a few of those messages. Running Controller 7.0.230.0 and WCS 7.0.230.0 and many 3500 and 1142 APs.

I once checked a few of those alerts and they seemed to come from old iPhones 3G running a 3.x iOS release. Might be a software issue on those models. But that is just a guess on my side. I haven't invested all that much time into it.

Have you got any more information about this, or are we the only ones receiving this kind of errors?   

[Stephen Rodriguez]

take a look at this previous thread.

https://supportforums.cisco.com/message/3460743#3460743

Steve

[sro]

Hi patoberli

I have a customer with the same problem. Every day he got also about 20 "security risk "WIFI Inverted" is detected" per day.My customer has many 3502 APs, and the wism i running 7.0.116.

I have tried to find the inverted WIFI, with my spectrum expert card. I can see the inverted WIFI with spectrum expert, but I was not able to find them physically. After 1-2 minutes they disapeer again.

So I see a semilar problem like you patoberli.

You wrote that it possible was and old iPhone 3G with IOS 3.x. Have you invested more time into this ?

I hope to here from you :-)

Soren

[patoberli]

Hi Soren

No I haven't spent anymore time. I actually don't even remember how I found the Macaddress of those "Inverted Wifi" devices. But like you, they disappear after some seconds/minutes and thus I don't really care.

-

pato

[Mark Lancaster]

Updating this older thread with some info.  I was running spectrum expert around a new 3500 AP, and I noticed "WiFi Inverted" signals detected when the AP was in monitor or Spectrum Expert mode.