Can interference cause a radio to reset?

[u297863AG]

Can interference cause a radio to  reset? I'm seeing some interference being reported in the alarm  logs. I've also noticed the radios reset as well. Can interference cause  this or could there be a problem with the actual AP?

Interference threshold violation reported by '802.11b/g/n' interface of AP , connected to Controller

'802.11b/g/n' interface of AP  associated to controller is down. Reason: Radio interface reset.

802.11b/g/n' interface of AP  associated to controller is down. Reason: Radio interface has been shutdown.

[Scott Fella]

I have never seen interference reset a radio. What you are seeing are threshold violations in which you can adjust if you want. There can be many things why a radio get reset, but many times it's a faulty radio.

If you console into the AP, does the output show any errors? When the interface resets, do you have to reboot the AP? If you telnet or ssh into the AP, do you see any crash logs?

When I have a trouble AP, I usually just delete the images and upload a new rcv image to the AP. I also would erase the nvram:

debug lwapp console cli
debug capwap console cli
erase /all nvram

*******************************************************
Example:

Entered the username and password
debug capwap console cli
erase /all nvram:
[confirm]
undebug all
reload
[confirm]

*******************************************************
Hold reset for over 30 seconds to get to ROMMON

ap:delete flash:private-config
ap:delete flash:private-multiple-fs
ap:boot

Your AP will be factory default


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[Scott Fella]

You should also post more info. WLC model, code version, access point having issue, specific AP or not, how often does it happen, have you tried swapping AP's around to see if the issues stays with that ap or not?

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[u297863AG]

It appears the radios have not reset since Friday. I was changing the power levels Friday and maybe that caused the radios to reset? I didnt think changing power levels would cause this, I thought only changing the channel. Can someone confirm? For 3602 APs with 5508 controllers running 7.2.110.0.

[Sandeep Choudhary]

Hi,

Unless there is a bug, excessive RF interference will cause radio resets but will not cause it to reboot. They do not take very long to reset, but even if they did NOT reset, exessive interference could make it much more difficult to pass traffic. To determine what is the cause if your issue, you should (1) Look at the Controller's RF dashboard to see interference, channel busy and utilization (2) Possibly get a spectrum analyzer to see if there is anything stopping your transmission.

If you are still having problems, you should open a TAC case so that they can look over your config in details and come up with some reasons to your issue.

Hope it helps.

Regards

Dont forget to rate helpful posts.

[u297863AG]

Ok thanks. Currenlty I am seeing a 'WiMax Fixed' persistant interference device. What type of device could this be?

[Sandeep Choudhary]

HI,

Check this:

http://www.cisco.com/en/US/docs/wireless/controller/7.5/config_guide/b_cg75_chapter_010000101.html

May be : http://en.wikipedia.org/wiki/List_of_devices_with_WiMAX

http://en.wikipedia.org/wiki/WiMAX

Regards

[Scott Fella]

When changing anything, you run into a risk of resetting the radios or glitch inf the wireless. If you don't make changes and you don't see these resets anymore, I wouldn't worry about it.

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