06-08-2012 02:53 PM
Our team have been focusing on limiting co-channel interference as much as possible with new deployments of Aruba APs. We are often stumped as to why ARM would place two APs in close proximity on the same channel. These poor channel choices by ARM are contributing to CCI in areas where they should not be a concern. To solve this I am adjusting the Free Channel Index threshold in the ARM profile to make the APs more sensitive to neighboring channels. However, I need to set the Free Channel Index threshold to 10 (25 is default) to get the desired results. I believe this is the minimum value allowed. Some APs report an interferrance index of 12 or 13 which is way below the default threshold of 25. Client Aware is still on so I have no worry of channels changing when active users are present. Is there any downside I should be aware of when I set this value to its very minimum?
06-08-2012 03:56 PM
You may need to have the logs on your controller analyzed so you can get specific information about your environment. Very few environments require changes to the ARM parameters, but when they do, it is usually done with the engagement of support to get the desired results. In the 2.4 ghz band, if you have a medium to dense deployment with poor isolation there are very few choices which channels APs can be deployed. If you are dense enough, access points in the next room could certainly end up on the same channel, because coverage is not the only thing measured when choosing a channel. it is also quite possible that an AP can see another AP above or below it stronger than the one next to it, and that will affect its decision, as well
Please contact support to ensure that your config is optimized for your specific situation.
Please also take a look at the knowledgebase article about ARM here: http://support.arubanetworks.com/Default.aspx?tabid=111&loc=https://kb.arubanetworks.com/app/answers/detail/a_id/927
Aruba Customer Engineering
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