Re: Cisco 9800-40 WLC CleanAir Interference Devices

Jay233 · ‎01-16-2023

Hi All,

Seeing a lot of interferers in the 2.4 & 5 GHz bands on the controller, what's more worrying is the reported severity and duty cycle of the devices. Examples below:

2.4GHz

5GHz

Any information on how to identify each device correctly, what is the reported MAC (checked no vendor) address? How to track down devices etc would be really useful.

Leo Laohoo · ‎01-16-2023

I do not care about interference on 2.4 Ghz -- Everyone knows it is a hopeless case.

I, however, would look at interference on 5.0 Ghz.

Look at the table from right-hand side to the Left-hand side.

Duty Cycle of 100% + RSSI value of the interferer. That is how I "calculate" MY severity level.

The interferer of the 5.0 Ghz have an RSSI value of >90 dBm. That is very weak for any concern.

Jay233 · ‎01-17-2023

Many thanks Leo,

That's really what I've already stated "what's more worrying is the reported severity and duty cycle of the devices", could you give me an idea of what the MAC address reported is as this MAC block (b47X) isnt showing as a vendor. Would you also know where I could get an explanation of "interferer Type" for the 9800/9120axi, assume this is calculated from an already pre-composed spectrum pattern of each interferer device seen, a bit like AirMagnet/Ekahau spectrum analysis.

What are your thoughts on trying to track down the sources of interference, obviously this must be physical but would you install sensors, survey, DNAC with spaces to try and locate the interferers on a map etc.

Cheers,

Leo Laohoo · ‎01-17-2023

@Jay233 wrote:
could you give me an idea of what the MAC address reported is as this MAC block (b47X) isnt showing as a vendor.

No, the "MAC address" is just a randomly-generated address and has no relationship whatsoever with interferer.

@Jay233 wrote:
Would you also know where I could get an explanation of "interferer Type" for the 9800/9120axi, assume this is calculated from an already pre-composed spectrum pattern of each interferer device seen, a bit like AirMagnet/Ekahau spectrum analysis.

Unlike Cisco Spectrum Expert, the new implementation of the WLC and IOS-XE no longer "fingerprints" interferer. (It is just an "interferer" in the eyes of Cisco. I have asked our Cisco AM/SE and WLBU to put the fingerprints back in but it was an exercise of futility. Maybe because we are not a very, very, very large customer.)

In Cisco Spectrum Expert, it would give an indication what is interferer. It was not accurate but it was still better than nothing at all. Walking around with an Ekahau SideKick would be ideal to locate the interferer.

@Jay233 wrote:
What are your thoughts on trying to track down the sources of interference, obviously this must be physical but would you install sensors, survey, DNAC with spaces to try and locate the interferers on a map etc.

As far as I am concerned, anybody who wants to identify and locate any WiFi interferer would benefit from Ekahau SideKick. No Cisco product (1800s, DNAC, DNA Spaces, etc) can replicate SideKick. (Read between the lines.)