AP C9130AXI-B 0DB on AP Channel Noise

[anthonymurphy586]

I have AP C9130AXI-B showing 0DB on AP Channel Noise in prime throughout the day. Currently, the controller is 9800. I also am having issues with iPhone users connecting and disconnecting from these APs. I'm not sure if it's an iPhone issue or if it is in fact an AP or controller issue. Any guidance will be helpful. Thank you.

[Scott Fella]

Start to try to isolate the issue.  If this is only on iPhones, or any specific model or firmware?  Issues with environment would affect more than just iPhones.  Determine what devices specifically, see if you can reproduce it and run a debug.  

[anthonymurphy586]

Thanks for the comment! Several people have complained about the same issues in different locations with the new C9130AX. So the issue is affecting other people. 

[Scott Fella]

Have you been able to replicate the issue?  If the issue is now with other devices, you should look at the wlan configuration to make sure you didn't enable a feature that might cause issues with devices.  One way to do this is to create a new test SSID that is open (don't start enabling features) and perform test with multiple devices.  If this works fine, then you know that the issue might be with the configuration.  Then setup the SSID your are testing with PSK and do the same testing.  Then if you are using 802.1x, start testing with that.  The purpose of this is to see when the issue starts to happen.

[David Ritter]

and maybe a site survey and spectrum analysis for the noise question.

[anthonymurphy586]

I agree. We just did not see this being an issue since the new APs are being replaced and there were never known issues with the old ones. 

[Scott Fella]

So new ap's are being put in, what was the old?  AP's on the 9800?

[ammahend]

for this AP, can you share this output from controller

"show ap auto-rf dot11 24ghz <ap name>"

[anthonymurphy586]

AP Name : AP-
MAC Address : 3891.b79a.7ea0
Slot ID : 0
Radio Type : 802.11ax - 2.4 GHz
Subband Type : All
Noise Information
Noise Profile : Passed
Channel 1 : -81 dBm
Channel 2 : -84 dBm
Channel 3 : -57 dBm
Channel 4 : -84 dBm
Channel 5 : -47 dBm
Channel 6 : -87 dBm
Channel 7 : -86 dBm
Channel 8 : -88 dBm
Channel 9 : -88 dBm
Channel 10 : -85 dBm
Channel 11 : -78 dBm
Channel 12 : -128 dBm
Channel 13 : -128 dBm
Channel 14 : -128 dBm
Interference Information
Interference Profile : Passed
Channel 1 : -128 dBm @ 0% busy
Channel 2 : -128 dBm @ 0% busy
Channel 3 : -128 dBm @ 0% busy
Channel 4 : -128 dBm @ 0% busy
Channel 5 : -128 dBm @ 0% busy
Channel 6 : -59 dBm @ 8% busy
Channel 7 : -128 dBm @ 0% busy
Channel 8 : -128 dBm @ 0% busy
Channel 9 : -128 dBm @ 0% busy
Channel 10 : -128 dBm @ 0% busy
Channel 11 : -128 dBm @ 0% busy
Channel 12 : -128 dBm @ 0% busy
Channel 13 : -128 dBm @ 0% busy
Channel 14 : -128 dBm @ 0% busy
Rogue Histogram (20)
Channel 1 : 0
Channel 2 : 0
Channel 3 : 0
Channel 4 : 0
Channel 5 : 0
Channel 6 : 0
Channel 7 : 0
Channel 8 : 0
Channel 9 : 0
Channel 10 : 0
Channel 11 : 0
Channel 12 : 0
Channel 13 : 0
Channel 14 : 0
Load Information
Load Profile : Passed
Receive Utilization : 9%
Transmit Utilization : 23%
Channel Utilization : 45%
Attached Clients : 7 clients
Coverage Information
Coverage Profile : Passed
Failed Clients : 0 clients
Client Signal Strengths
RSSI -100 dBm : 0 clients
RSSI -92 dBm : 0 clients
RSSI -84 dBm : 0 clients
RSSI -76 dBm : 0 clients
RSSI -68 dBm : 1 clients
RSSI -60 dBm : 2 clients
RSSI -52 dBm : 4 clients
Client Signal to Noise Ratios
SNR 0 dB : 0 clients
SNR 5 dB : 0 clients
SNR 10 dB : 0 clients
SNR 15 dB : 0 clients
SNR 20 dB : 0 clients
SNR 25 dB : 0 clients
SNR 30 dB : 1 clients
SNR 35 dB : 1 clients
SNR 40 dB : 4 clients
SNR 45 dB : 1 clients
Nearby APs
AP 7411.b217.d700 slot 0 : -34 dBm on ( 1, 20 MHz)
AP 8c1e.8059.17c0 slot 0 : -50 dBm on ( 11, 20 MHz)
AP 345d.a815.8640 slot 0 : -54 dBm on ( 1, 20 MHz)
AP 3891.b79a.8da0 slot 0 : -56 dBm on ( 1, 20 MHz)
AP 8c1e.8059.1060 slot 0 : -58 dBm on ( 6, 20 MHz)
AP 345d.a815.8ce0 slot 0 : -59 dBm on ( 11, 20 MHz)
AP 8c1e.8059.0300 slot 0 : -62 dBm on ( 1, 20 MHz)
AP 9cd5.7d62.fde0 slot 0 : -62 dBm on ( 6, 20 MHz)
AP 8c1e.8059.10a0 slot 0 : -64 dBm on ( 11, 20 MHz)
AP 5006.04e3.f9a0 slot 0 : -65 dBm on ( 6, 20 MHz)
AP 8c1e.8059.1460 slot 0 : -66 dBm on ( 1, 20 MHz)
AP 345d.a815.9320 slot 0 : -67 dBm on ( 11, 20 MHz)
AP 70ea.1ad6.32e0 slot 0 : -68 dBm on ( 1, 20 MHz)
AP 7411.b217.d4a0 slot 0 : -69 dBm on ( 11, 20 MHz)
AP b862.1f1c.fcd0 slot 0 : -71 dBm on ( 1, 20 MHz)
AP 7411.b217.d300 slot 0 : -72 dBm on ( 11, 20 MHz)
AP 7010.5c1f.3fe0 slot 0 : -74 dBm on ( 11, 20 MHz)
AP a418.75b2.4980 slot 0 : -75 dBm on ( 1, 20 MHz)
AP 2c36.f8b8.7000 slot 0 : -75 dBm on ( 1, 20 MHz)
AP 7010.5c1f.2750 slot 0 : -75 dBm on ( 11, 20 MHz)
AP c8f9.f95b.3150 slot 0 : -76 dBm on ( 11, 20 MHz)
AP 7010.5c1f.0ad0 slot 0 : -76 dBm on ( 11, 20 MHz)
AP e8ba.7060.a1f0 slot 0 : -76 dBm on ( 1, 20 MHz)
Radar Information
Detected Channels
Blacklist Times
Channel changes due to radar : 0
DFS Statistics with Cisco Integrated RF ASIC
Filtered events on serving radio : 0
Filtered events on Cisco Integrated RF ASIC : 0
Triggered radar events : 0
DFS statistics last updated : 431907 seconds ago
Channel Assignment Information
Current Channel Average Energy : -62 dBm
Previous Channel Average Energy : -43 dBm
Channel Change Count : 16
Last Channel Change Time : 04/11/2023 10:38:20
Recommended Best Channel : 6
RF Parameter Recommendations
Power Level : 6
RTS/CTS Threshold : 0
Fragmentation Threshold : 0
Antenna Pattern : 0
Persistent Interference Devices
Class Type Channel DC (%%) RSSI (dBm) Last Update Time
------------------------- ------- ------ --------- ----------------

Thanks for your help! Let me know if you see something funky. I do not. 

[JPavonM]

Channel Utilization is too high in this band.
There are lot of APs opearting in 2.4 GHz here, sharing the same channel (from the 3 channels available on this band), and that increase not only Ch Util but also congestion through contention management

How is the issue like in 5 GHz band? I would recommend you to stop broadcasting the SSID in 2.4 GHz to see how is it like there.

Additionally, as @Scott Fella asked before, were the old APs also setup in C9800? Which C9800 code are you running?
Have you checked for non Wi-Fi interferences conducting a WLAN validation survey as @David Ritter mentioned? Nise on Ch5 and Ch7, and Interference Profile in Ch6 seems to be abnormally high.

[anthonymurphy586]

The old APs were on a different controller and is running 17.3.6. I will be conducting a survey soon. 

"There are lot of APs opearting in 2.4 GHz here, sharing the same channel" - Where do you see this at?

[JPavonM]

That's in your previous output:

Nearby APs
AP 7411.b217.d700 slot 0 : -34 dBm on ( 1, 20 MHz)
AP 8c1e.8059.17c0 slot 0 : -50 dBm on ( 11, 20 MHz)
AP 345d.a815.8640 slot 0 : -54 dBm on ( 1, 20 MHz)
AP 3891.b79a.8da0 slot 0 : -56 dBm on ( 1, 20 MHz)
AP 8c1e.8059.1060 slot 0 : -58 dBm on ( 6, 20 MHz)
AP 345d.a815.8ce0 slot 0 : -59 dBm on ( 11, 20 MHz)
AP 8c1e.8059.0300 slot 0 : -62 dBm on ( 1, 20 MHz)
AP 9cd5.7d62.fde0 slot 0 : -62 dBm on ( 6, 20 MHz)
AP 8c1e.8059.10a0 slot 0 : -64 dBm on ( 11, 20 MHz)
AP 5006.04e3.f9a0 slot 0 : -65 dBm on ( 6, 20 MHz)
AP 8c1e.8059.1460 slot 0 : -66 dBm on ( 1, 20 MHz)
AP 345d.a815.9320 slot 0 : -67 dBm on ( 11, 20 MHz)
AP 70ea.1ad6.32e0 slot 0 : -68 dBm on ( 1, 20 MHz)
AP 7411.b217.d4a0 slot 0 : -69 dBm on ( 11, 20 MHz)
AP b862.1f1c.fcd0 slot 0 : -71 dBm on ( 1, 20 MHz)
AP 7411.b217.d300 slot 0 : -72 dBm on ( 11, 20 MHz)
AP 7010.5c1f.3fe0 slot 0 : -74 dBm on ( 11, 20 MHz)
AP a418.75b2.4980 slot 0 : -75 dBm on ( 1, 20 MHz)
AP 2c36.f8b8.7000 slot 0 : -75 dBm on ( 1, 20 MHz)
AP 7010.5c1f.2750 slot 0 : -75 dBm on ( 11, 20 MHz)
AP c8f9.f95b.3150 slot 0 : -76 dBm on ( 11, 20 MHz)
AP 7010.5c1f.0ad0 slot 0 : -76 dBm on ( 11, 20 MHz)
AP e8ba.7060.a1f0 slot 0 : -76 dBm on ( 1, 20 MHz)

[anthonymurphy586]

The thing I do not understand is it says there are 23 APs nearby. (assuming I'm reading that correctly). There are not even 23 APs installed in the building I'm in. 

[Scott Fella]

This is the thing, we have no information on how many ap's you have.  You didn't mention if there is an adjacent organization with nearby wireless or if you are running mobility between the two controllers?  The more information you can provide, the better.  Maybe a screen shot of the floor plan with your ap locations and the show ap summary or a list of the ap's on both controllers.  

[Rich R]

And don't forget many printers/screens etc broadcast themselves as an AP for users to connect directly.
And every mobile phone is capable of being a personal hotspot now.

17.3 is going end of life - think about moving to 17.9.3

You don't say what the old APs, WLC and software version were - but quite likely you have numerous new features enabled on the new APs which weren't enabled or supported on the old ones - which goes back to @Scott Fella's point on working out which new feature(s) might be causing your problems.