Wireless Access

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Access network design for branch, remote, outdoor, and campus locations with HPE Aruba Networking access points and mobility controllers.
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Channel hopping & Interference on 5Ghz

This thread has been viewed 4 times
  • 1.  Channel hopping & Interference on 5Ghz

    Posted Jul 04, 2014 12:47 PM

    Hi,

     

    I am seeing a number of my APs hop excessively throughout the day (10+ times).  This doesn't seem right, but looking over the AirWave states reasons such as Empty Channel and Interference.

     

    Additionally, I am seeing high Interference >20% on some 5Ghz channels which seems to correspond the times of actual channel utilization.  This, too, doesn't seem right unless Interference is somehow related to channel use.

     



  • 2.  RE: Channel hopping & Interference on 5Ghz

    EMPLOYEE
    Posted Jul 04, 2014 04:05 PM

    Try to use 20 mhz channels if possible.  If any channel in a bundle shows interference, it will change channels.  Statistically it is more likely to notice interference when you are bonding channels.



  • 3.  RE: Channel hopping & Interference on 5Ghz

    Posted Jul 06, 2014 04:46 PM

    That makes total sense.  

     

    Aside from doing that, is there an automated way to get controller or airwave to pick up what the source and location of the interference is?  If not, what do peope usually recommend to get this information?

     

    Also, is there a particular reason why AP moves from one channel to another just because it's free. I get the reasoning behind channel switching for interference but simply change a channel because its free doesn't seem right.

     

    Thanks.



  • 4.  RE: Channel hopping & Interference on 5Ghz

    EMPLOYEE
    Posted Jul 06, 2014 05:10 PM
    Free channel < interference than a channel with devices. You should use client aware if you don't want access points to change channels when users are connected.


  • 5.  RE: Channel hopping & Interference on 5Ghz

    EMPLOYEE
    Posted Jul 06, 2014 05:14 PM
    To track things down typically a handheld spectrum analyzer is the best way to find something that is in a fixed area. Even with something like a spec-an with a directional antenna it is difficult to locate. ARM is designed to avoid interference so that your clients can have relief sooner.


  • 6.  RE: Channel hopping & Interference on 5Ghz

    Posted Jul 06, 2014 05:35 PM

    Thanks a lot, Colin!

     

    Does anyone have any opinions on using wi-spy for finding the source of interference?  Or, perhaps some other tool that can give me both 2.4 & 5 coverage?

     

    Also, returning back to my original question, why do I see corelation between channel utilization and interference?



  • 7.  RE: Channel hopping & Interference on 5Ghz

    EMPLOYEE
    Posted Jul 06, 2014 05:41 PM
    There are users that use the wi spy and get good results. It would be good to hear what other users use and their experiences. I don't have much experience with the with wi spy.

    Channels that have more traffic will have more sampling vs. Channels that are only sampled as part of an off-channel scan, so it stands to reason that there will be more DATA about that channel.


  • 8.  RE: Channel hopping & Interference on 5Ghz
    Best Answer

    Posted Jul 07, 2014 02:39 PM

    Frequent sampling of the used channels makes perfect sense.  What doesn't make sense is fhe fact that interference moves in lock-step with the utilization, unless of course interference implicitely implies utilzation.



  • 9.  RE: Channel hopping & Interference on 5Ghz
    Best Answer

    EMPLOYEE
    Posted Jul 07, 2014 03:07 PM
    Channel utilization is a total of everything including interference.