Wireless Access

Occasional Contributor I

free channel index

I have 5 AP deployed in each of three floors in the same building. The last floor's APs are using basically the same channel in 2,4GHz band with the following pattern:  11 - 11- 1- 11- 11.


Here is an extract of the output of a 'show ap arm rf-summary apname (1st AP using ch11)'


channel  retry  phy-err  mac-err  noise  cov-idx(Total)  intf_idx(Total)
-------  -----  -------  -------  -----  --------------  ---------------
1 0 0 0 92 5/12(17) 37/8//155/110(310) 6 0 0 0 94 3/7(10) 50/13//640/81(784) 11 0 0 3 94 6/13(19) 47/8//217/122(394)
Current ARM Assignment :11/9

 ARM is enabled and the free channel index is 25 (default).

This Ap should move to channel 1 since total intf_idx  difference (394 - 310) is greater than   free channel index (25), shouldn't it?


Thank you.

Valued Contributor II

Re: free channel index



Changing the channel of an AP is  not only depends on this(arm free-channelindex) criteria, it also depends on others,


1. If "client-aware" is enabled and clients are connected to AP then AP will not change it's channel.

2. AP will not change it's channel untill the "arm backoff-time" is not reached zero.

3. if all the above criteria matches, AP will wait for "arm wait-time" then chages it's channel.


Hope you understood the criteria,


Please feel free to comeback if want to know some more details about ARM :)




Venu Puduchery

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Venu Puduchery,
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Guru Elite

Re: free channel index

The AP should consider moving that channel, BUT...it has to have scanned that channel (minimum scan times) 8 times before considering to move to that channel and it also have to wait (backoff time) 240 seconds before changing.  If the interference index changes in that time, it might not consider moving to that channel, at all. 


Having client-aware, voip aware or video aware will also stop if from changing channel.

*Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba Networks or Hewlett Packard Enterprise.*
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Occasional Contributor I

Re: free channel index


Thus it doesn't seems an issue.

Thank you a lot!

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