Clean Air Specifics

[william.briere]

Hi,

It is my understanding that when I enable Cisco Clean-Air on my 2602 AP's that currently host my SSID's it will still scan all channels. I spoke to a colleague who tells me that it will not scan all channels and instead will only scan the active channel. That colleague tells me that the only way for Clean-Air to scan all channels is for the AP to be dedicated for that purpose (Clean-Air).

Experts, which is the correct answer?

Thanks.                   

[Erwin Salazar]

William,

By default I do believe it will indeed scan all channels.  You can confirm this by going into the controller GUI under Wireless > 802.11a/n or 802.11b/g/n > RRM > General.  Here you can specify if you want 'All Channels', 'Country Channels', or simply 'DCA Channels'.

Cheers,

Erwin

[George Stefanick]

If its in to local mode it will scan only the active channel .. You can read about monitor mode and spectrum mode in the below link ..

http://www.cisco.com/en/US/products/ps10315/products_tech_note09186a0080b4bdc1.shtml

CleanAir AP Modes of Operation

Local Mode AP (recommended) (LMAP)—A Cisco CleanAir AP operating in LMAP mode is serving clients on it’s assigned channel. It is also monitoring the Spectrum on that channel and that channel ONLY. Tight silicon integration with the Wi-Fi radio allows the CleanAir hardware to listen between traffic on the channel that is currently being served with absolutely no penalty to throughput of attached clients. That is line rate detection without interrupting client traffic.

There are no CleanAir dwells processed during normal off channel scans. In normal operation, a CUWN Local Mode AP executes an off channel passive scans of the alternate available channels in 2.4 GHz and 5 GHz. Off channel scans are used for system maintenance such as RRM metrics and rogue detection. The frequency of these scans is not sufficient to collect back to back dwells required for positive device classification, so information gleaned during this scan is suppressed by the system. Increasing the frequency of off channel scans is also not desirable, as it takes away from time that the radio services traffic.

What does this all mean?

A CleanAir AP in LMAP mode only scans one channel of each band continuously. In normal enterprise densities there should be plenty of APs on the same channel, and at least one on each channel assuming RRM is handling channel selection. An interference source that uses narrow band modulation (operates on or around a single frequency) is only detected by APs that share that frequency space. If the interference is a frequency hopping type (uses multiple frequencies – generally covering the whole band) it is detected by every AP that can hear it operating in the band.

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"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
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‎"I'm in a serious relationship with my Wi-Fi. You could say we have a connection."

[Erwin Salazar]

George is correct

I had confused CleanAir with Rogue Detection

[william.briere]

Hi,

I am running the AP's using Flex Connect mode. Does that change the answer at all?

Thanks in advance.

[Chris Illsley]

No it doesn't.

Thanks

Chris

[Abhishek Abhishek]

Hello,

As per your query i can suggest you the following link to refer for clean air specifications in 2602 AP-

http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps12534/data_sheet_c78-709514.html

Hope this will help you.