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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Remote APs interfering chose wrong channel

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  • 1.  Remote APs interfering chose wrong channel

    Posted Jul 10, 2017 07:15 AM

    Hi 

    i fugire out some strange behaviour. We installed some remote accesspoints in homeoffices. Customers now reporting that the RAPs influence their privat wifi networks. So i did some investigation in this topic and got the result raps are choosing same channels as the private networks. ARM is configured as shown below:

    arm.JPG

    We have ARM enabled so i would expect AP would scann the air and would choos an unused channel. 

     



  • 2.  RE: Remote APs interfering chose wrong channel

    EMPLOYEE
    Posted Jul 10, 2017 07:17 AM

    What model RAP is this?

    What channel is it choosing?



  • 3.  RE: Remote APs interfering chose wrong channel

    Posted Jul 10, 2017 07:19 AM

    It is an AP-225 configured as RAP.

    In my example private wifi in homeoffice is channel 6 and if Aruba AP boots it chooses channel 6 too.



  • 4.  RE: Remote APs interfering chose wrong channel

    EMPLOYEE
    Posted Jul 10, 2017 07:37 AM

    ARM chooses the channel based on the interference index, not how many APs are on the same channel.  There is other interference on the 2.4ghz band besides access points.

     

    Use the command:

     

    show ap arm rf-summary ap-name <name of ap>

    to see what the interference index (intf_indx Total) is.   Again, there is little room on the 2.4ghz band, so I would consider using 5ghz if possible.

     

     



  • 5.  RE: Remote APs interfering chose wrong channel

    Posted Jul 10, 2017 07:54 AM

    arm_interference.JPGinterference index is 84. The other channels look better. Why AP is choosing channel 6?



  • 6.  RE: Remote APs interfering chose wrong channel

    EMPLOYEE
    Posted Jul 10, 2017 08:23 AM

    What is the output of "show ap arm history ap-name"?



  • 7.  RE: Remote APs interfering chose wrong channel

    Posted Jul 10, 2017 09:12 AM

    arm_interference2.JPG



  • 8.  RE: Remote APs interfering chose wrong channel

    EMPLOYEE
    Posted Jul 10, 2017 12:16 PM

    It is possible that the AP has not scanned the potential channel that it could go to (1) enough times to consider that channel.  Thinks like Video and Voice aware scanning pause scanning and stop this.  Channel 11 has a noise value of 76, so it is not a good candidate.  More info on why that AP might not be changing channels is here:  https://community.arubanetworks.com/aruba/attachments/aruba/unified-wired-wireless-access/7592/1/ARM%20Doc%20Supplement.pdf

     

    Again, just existing on the same channel as  other access points does not mean performance is suboptimal...



  • 9.  RE: Remote APs interfering chose wrong channel

    Posted Jul 11, 2017 01:26 AM

    Problem is customer's private wifi is not working till the remote AP is activated. For my opinion it is caused by choosing same channel.



  • 10.  RE: Remote APs interfering chose wrong channel

    EMPLOYEE
    Posted Jul 11, 2017 06:36 AM

    "activated"?  Do you have any IDS/IPS configured that would be stopping that wifi?



  • 11.  RE: Remote APs interfering chose wrong channel

    Posted Jul 11, 2017 07:27 AM

    I'm sorry I should be "deactivated"



  • 12.  RE: Remote APs interfering chose wrong channel

    EMPLOYEE
    Posted Jul 12, 2017 08:59 AM

    Please note that having 2 APs (RAP and end user's AP) really close to each other will cause low-level interference issues as well. If you can try to separate them by a concrete wall, or 3 meter/10ft distance the problem may have gone.