Cisco CleanAir Express


The CleanAir technology in Cisco’s access-point’s comes originally from the Cognio acquisition back in 2007. Cognio had a hardware chip that could do spectrum analysis and recognize non wifi interference. After this acquisition Cisco integrated this hardware capability right into its access-point’s. The first access-point with this technology was the 3500 and since then all the 2×00 and 3×00 access-points have CleanAir support.

An commonly misunderstanding is that the CleanAir makes an access-points change its channel when it discovers a (strong) non-wifi interference on the channel the access-point is currently on. RRM is the part of the WLC that is responsible for the power and channel configuration of your access-point, not CleanAir. CleanAir only detects. However, when you enable event driven RRM (EDRRM), the RRM algorithm will take the CleanAir information into account.

CleanAir Express

CleanAir Express was announced together with the 1600 access-point, but was not usable at the time due to the lack of software support. The only thing that Cisco published about this subject was that “it” was done in software on the access-point’s instead of doing it in hardware. Since than it is chaos around this subject because nobody really knows what to expect from CleanAir Express…

The documentation available today from Cisco on CleanAir Express does not help either. The primary reason for this (which I can think of) is that CleanAir Express has just been implemented since software 8.0, which is still fairly new and the marking people needed something to show earlier than the release of that code. A nice example is this document that states that “Air Qualty Index” is not supported with CleanAir Express, but from my own experience I can tell you that this just does work on 1600 and 1700 AP’s while running 8.0.110 code. See the example below.

(vWLC) >show ap inventory 1602E
NAME: “Cisco AP”    , DESCR: “Cisco Wireless Access Point”
PID: AIR-CAP1602E-E-K9,  VID: V01,  SN: FGL1734xxxxx

(vWLC) >show 802.11b cleanair air-quality 1602E
AQ = Air Quality

DFS = Dynamic Frequency Selection

Channel Avg AQ Min AQ Total Power (dBm) Total Duty Cycle (%) Interferer Power (dBm) Interferer Duty Cycle (%) Interferers DFS
——- —— —— —————– ——————– ———————- ————————- ———– —
1       98     98     -92               1                    -72                    2                         1


So what are the big differences between CleanAir and CleanAir Express? Well, from my experiences and from a functional standpoint there are no significant differences anymore since there is finally software which enables CleanAir Express. Because of it architecture CleanAir Express can only track up to three devices per radio (instead of 10) and it is somewhat a little slower, but for me that is now real deal breaker.

It is a pity that it took Cisco almost 2 years to enable it, but it is here and it does even more than the marketing people did told us upfront..  🙂