topic Re: DCA leaving APs on channels with over 40 percent utilization. in Wireless

DCA leaving APs on channels with over 40 percent utilization.

rhallan — Fri, 18 Jul 2025 18:06:04 GMT

Using Model 9800-40 WLCs with Model 9164 APs running version 17.12.4.

We have APs that are staying on channels with over 40% utilization and not changing channels under DCA even though there are lot of APs with very low channel utilization. The high utilization on these APs is due to interference and not client load.

DCA and EDRRM sensitivity at medium.

I realize that DCA decision are complex and DCA uses cost metrics to make decisions. It not only uses APs neighbors, but the neighbors neighbors. It uses the same channels contentions. It even uses a normalized cumulative cost function.....

I tried to open a TAC case to investigate this and they indicated RRM is working fine and they are not able to answer questions on DCA as it is propriety information.

1. Are there any tools to analyze DCA channels selection/decisions ?

2. Is there a way or commands to display the cost metric ?

If not, what are some of the other data points/commands I can use to review channel selection ?

3. In the "show ap dot11 5ghz channel" What do the "Channel Energy Levels" mean and how do they come into play in DCA ?

------------------ show ap dot11 5ghz channel ------------------

Leader Automatic Channel Assignment

Channel Assignment Mode : AUTO

Channel Update Interval : 24 Hours

Anchor time (Hour of the day) : 6

Channel Update Contribution

Noise : Enable

Interference : Enable

Load : Disable

Device Aware : Enable

CleanAir Event-driven RRM option : Enabled

CleanAir Event-driven RRM sensitivity : LOW

CleanAir Event-driven RRM Rogue option : Disabled

Zero Wait DFS : Enabled

Channel Assignment Leader : xxxx

DCA Sensitivity Level : MEDIUM : 15 dB

DCA 802.11n/ac Channel Width : best

DBS Max Channel Width : 40 MHz

DCA Minimum Energy Limit : -95 dBm

DCA Aggressive on startup : Enabled

Channel Energy Levels

Minimum : -86 dBm

Average : -81 dBm

Maximum : -66 dBm

Thanks in advance for you input.

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Fri, 18 Jul 2025 18:36:57 GMT

show wireless ap config general <AP_NAME>

Share this for AP with issue

MHM

Re: DCA leaving APs on channels with over 40 percent utilization.

Mark Elsen — Fri, 18 Jul 2025 19:14:27 GMT

- @rhallan FYI : https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwn38908

Re: DCA leaving APs on channels with over 40 percent utilization.

rhallan — Fri, 18 Jul 2025 19:21:55 GMT

The syntax may be a bit different than the command show wireless ap config general <AP_NAME> you shared.

I used show ap name xxxx config dot11 5ghz, not sure if this is the information you were looking for.

show ap name xxxxxxx config dot11 5ghz
Cisco AP Identifier : xxxxxx
Cisco AP Name : xxxxxxx
Country Code : CA
Regulatory Domain Allowed by Country : 802.11bg:-A 802.11a:-A 802.11 6GHz:-A
AP Country Code : CA - Canada
AP Regulatory Domain : -A
MAC Address : xxxxxxx
IP Address Configuration : DHCP
IP Address : Disabled
Telnet State : Disabled
SSH State : Disabled
Serial Console State : Enabled
Cisco AP Location : xxxxxx
Site Tag Name : xxxxx
Administrative State : Enabled
Operation State : Registered
AP Mode : Local
ATF Mode : Disable
ATE Optimization : N/A
AP Submode : Not Configured
Remote AP Debug : Disabled
Logging Trap Severity Level : information
Software Version : 17.12.4.158
Boot Version : 1.1.2.4
Mini IOS Version : 0.0.0.0
Stats Reporting Period : 180
primary_discovery_timer : 120
LED State : Enabled
PoE Pre-Standard Switch : Disabled
PoE Power Injector MAC Address : Disabled
Power Type/Mode : PoE/Full Power
Number of Slots : 3
AP Model : CW9164I-A
IOS Version : 17.12.4.158
Reset Button : Disabled
AP Serial Number : FJC28321HUH
AP Certificate Type : Manufacturer Installed Certificate
AP Certificate Expiry-time : 08/09/2099 14:58:26
AP Certificate issuer common-name : High Assurance SUDI CA
AP Certificate Policy : Default
AP CAPWAP-DTLS LSC Status
Certificate status : Not Available
AP 802.1x LSC Status
Certificate status : Not Available
AP User Name : xxxxxxxx
AP 802.1X User Mode : Global
AP 802.1X User Name : Not Configured
Cisco AP System Logging Host : 255.255.255.255
AP Up Time : 83 days 1 hour 32 minutes 45 seconds
AP CAPWAP Up Time : 83 days 1 hour 30 minutes 29 seconds
Join Date and Time : 04/26/2025 11:37:29

Attributes for Slot 1
Radio Type : 802.11ax - 5 GHz
Radio Subband : All
Radio Mode : Local
Radio Role : Client Serving
Radio Role Op : Auto
Radio SubType : Main
Administrative State : Enabled
Operation State : Up

Station Configuration
Configuration : Automatic
Medium Occupancy Limit : 100
CFP Period : 4
CFP Maximum Duration : 60
BSSID : 70bc.48ad.4100
Operation Rate Set
802.11a 6M Rate : Unsupported
802.11a 9M Rate : Unsupported
802.11a 12M Rate : Mandatory
802.11a 18M Rate : Supported
802.11a 24M Rate : Supported
802.11a 36M Rate : Supported
802.11a 48M Rate : Supported
802.11a 54M Rate : Supported

MCS Set
MCS 0 : SUPPORTED
MCS 1 : SUPPORTED
MCS 2 : SUPPORTED
MCS 3 : SUPPORTED
MCS 4 : SUPPORTED
MCS 5 : SUPPORTED
MCS 6 : SUPPORTED
MCS 7 : SUPPORTED
MCS 8 : SUPPORTED
MCS 9 : SUPPORTED
MCS 10 : SUPPORTED
MCS 11 : SUPPORTED
MCS 12 : SUPPORTED
MCS 13 : SUPPORTED
MCS 14 : SUPPORTED
MCS 15 : SUPPORTED
MCS 16 : SUPPORTED
MCS 17 : SUPPORTED
MCS 18 : SUPPORTED
MCS 19 : SUPPORTED
MCS 20 : SUPPORTED
MCS 21 : SUPPORTED
MCS 22 : SUPPORTED
MCS 23 : SUPPORTED
MCS 24 : SUPPORTED
MCS 25 : SUPPORTED
MCS 26 : SUPPORTED
MCS 27 : SUPPORTED
MCS 28 : SUPPORTED
MCS 29 : SUPPORTED
MCS 30 : SUPPORTED
MCS 31 : SUPPORTED
802.11ac : Enabled
802.11ac MCS Settings:
MCS 8, Spatial Streams = 1 : Supported
MCS 9, Spatial Streams = 1 : Supported
MCS 8, Spatial Streams = 2 : Supported
MCS 9, Spatial Streams = 2 : Supported
MCS 8, Spatial Streams = 3 : Supported
MCS 9, Spatial Streams = 3 : Supported
MCS 8, Spatial Streams = 4 : Supported
MCS 9, Spatial Streams = 4 : Supported

802.11ax Parameters
HE Capable : Yes
BSS Color Capable : Yes
BSS Color Configuration : Automatic
BSS Color Status : Disabled
Current BSS Color : 33
OBSS PD Capable : Yes
OBSS PD SRG Capable : No
802.11ax : Enabled
802.11ax MCS Settings:
MCS 7, Spatial Streams = 1 : Supported
MCS 9, Spatial Streams = 1 : Supported
MCS 11, Spatial Streams = 1 : Supported
MCS 7, Spatial Streams = 2 : Supported
MCS 9, Spatial Streams = 2 : Supported
MCS 11, Spatial Streams = 2 : Supported
MCS 7, Spatial Streams = 3 : Supported
MCS 9, Spatial Streams = 3 : Supported
MCS 11, Spatial Streams = 3 : Supported
MCS 7, Spatial Streams = 4 : Supported
MCS 9, Spatial Streams = 4 : Supported
MCS 11, Spatial Streams = 4 : Supported
MCS 7, Spatial Streams = 5 : Supported
MCS 9, Spatial Streams = 5 : Supported
MCS 11, Spatial Streams = 5 : Supported
MCS 7, Spatial Streams = 6 : Supported
MCS 9, Spatial Streams = 6 : Supported
MCS 11, Spatial Streams = 6 : Supported
MCS 7, Spatial Streams = 7 : Supported
MCS 9, Spatial Streams = 7 : Supported
MCS 11, Spatial Streams = 7 : Supported
MCS 7, Spatial Streams = 8 : Supported
MCS 9, Spatial Streams = 8 : Supported
MCS 11, Spatial Streams = 8 : Supported

Beacon Period : 100
Fragmentation Threshold : 2346
Multi Domain Capability Implemented : False
Multi Domain Capability Enabled : False
Country String : CA

Multi Domain Capability
Configuration : Automatic
First Channel : 36
Number of Channels : 21

MAC Operation Parameters
Configuration : Automatic
Fragmentation Threshold : 2346
Packet Retry Limit : 64
RTS/CTS Threshold : 2347

Tx Power
Number of Supported Power Levels : 8
Tx Power Level 1 : 23 dBm
Tx Power Level 2 : 20 dBm
Tx Power Level 3 : 17 dBm
Tx Power Level 4 : 14 dBm
Tx Power Level 5 : 11 dBm
Tx Power Level 6 : 8 dBm
Tx Power Level 7 : 5 dBm
Tx Power Level 8 : 2 dBm
Tx Power Configuration : Automatic
Current Tx Power Level : 4
Tx Power Assigned By : DTPC

Phy OFDM Parameters
Configuration : Automatic
Current Channel : 161
Channel Assigned By : DCA
Extension Channel : BELOW
Channel Width : 40
Allowed Channel List : 36,40,44,48,52,56,60,64,100,104,108,112,116,132,136,140,149,153,157,161,165
DCA Channel List : 36,40,44,48,52,56,60,64,100,104,108,112,116,132,136,140,144,149,153,157,161
Antenna Type : INTERNAL_ANTENNA
Internal Antenna Gain (in .5 dBi units) : 10
Antenna Mode : ANTENNA_OMNI
Diversity : DIVERSITY_ENABLED

802.11n Antennas
Number of Antennas selected : 4
MIMO : 4x4
Supported Antenna modes : 1x1, 2x2, 4x4
160MHz Supported Antenna modes : 4x4

Performance Profile Parameters
Configuration : AUTOMATIC
Interference Threshold : 10%
Noise Threshold : -70 dBm
RF Utilization Threshold : 80%
Data-rate threshold : 1000000 bps
Client Threshold : 12 clients
Coverage SNR threshold : 70 dB
Coverage Exception Level : 25%
Client minimum exception level : 3 clients

CleanAir Management Information
CleanAir Capable : Yes
CleanAir Management Administration State : Enabled
CleanAir Management Operation State : Up
Rapid Update Mode : OFF
CleanAir NSI Key : 20b7403514e824d31050018a04cd0073
Spectrum Expert Connections counter : 0
CleanAir Sensor State : Configured
EDRRM Capable : Capable
CleanAir Version : CA-Pro

Radio Extended Configurations
Beacon period : 100 milliseconds
Beacon range : AUTO
Multicast buffer : AUTO
Multicast data-rate : AUTO
RX SOP threshold : DEFAULT
CCA threshold : AUTO

Rogue Containment Information
Containment Count : 0

Management Frame Information
Validation : Capable
Protection : Not capable
NDP capability : On-Off-channel
NDP mode : On-channel
Beam Selection : Not configured
Zero Wait DFS Parameters
Zero Wait DFS Capable : No

-----xxxxxxxx-----

Also sharing auto-rf information for AP below

show ap name xxxxxxx auto-rf dot11 5ghz
###################################################################

Number of Slots : 3
AP Name : xxxxxxx
MAC Address : xxxxxxxx
Ethernet MAC Address : xxxxxxxx
Slot ID : 1
Radio Type : 802.11ax - 5 GHz
Subband Type : All

Noise Information
Noise Profile : Passed
Channel 36 : -97 dBm
Channel 40 : -97 dBm
Channel 44 : -96 dBm
Channel 48 : -97 dBm
Channel 52 : -97 dBm
Channel 56 : -97 dBm
Channel 60 : -96 dBm
Channel 64 : -97 dBm
Channel 100 : -97 dBm
Channel 104 : -97 dBm
Channel 108 : -97 dBm
Channel 112 : -97 dBm
Channel 116 : -98 dBm
Channel 132 : -98 dBm
Channel 136 : -99 dBm
Channel 140 : -99 dBm
Channel 149 : -98 dBm
Channel 153 : -97 dBm
Channel 157 : -97 dBm
Channel 161 : -96 dBm
Channel 165 : -98 dBm

Interference Information
Interference Profile : Failed
Channel 36 : -89 dBm @ 1% busy
Channel 40 : -87 dBm @ 1% busy
Channel 44 : -82 dBm @ 37% busy
Channel 48 : -87 dBm @ 2% busy
Channel 52 : -85 dBm @ 10% busy
Channel 56 : -88 dBm @ 42% busy
Channel 60 : -82 dBm @ 8% busy
Channel 64 : -86 dBm @ 5% busy
Channel 100 : -87 dBm @ 5% busy
Channel 104 : -86 dBm @ 3% busy
Channel 108 : -78 dBm @ 3% busy
Channel 112 : -88 dBm @ 5% busy
Channel 116 : -88 dBm @ 5% busy
Channel 132 : -88 dBm @ 11% busy
Channel 136 : -74 dBm @ 1% busy
Channel 140 : -128 dBm @ 30% busy
Channel 149 : -88 dBm @ 8% busy
Channel 153 : -86 dBm @ 29% busy
Channel 157 : -82 dBm @ 38% busy
Channel 161 : -84 dBm @ 24% busy
Channel 165 : -128 dBm @ 0% busy

Rogue Histogram (20/40/80)
Channel 36 : 1/ 0/ 0
Channel 40 : 0/ 0/ 0
Channel 44 : 0/ 0/ 3
Channel 48 : 0/ 0/ 0
Channel 52 : 0/ 1/ 0
Channel 56 : 0/ 0/ 0
Channel 60 : 0/ 0/ 0
Channel 64 : 0/ 0/ 1
Channel 100 : 0/ 0/ 1
Channel 104 : 0/ 0/ 0
Channel 108 : 0/ 0/ 1
Channel 112 : 0/ 0/ 0
Channel 116 : 0/ 0/ 0
Channel 132 : 0/ 0/ 0
Channel 136 : 0/ 0/ 0
Channel 140 : 0/ 0/ 0
Channel 149 : 0/ 0/ 0
Channel 153 : 0/ 0/ 0
Channel 157 : 0/ 0/ 0
Channel 161 : 0/ 0/ 0
Channel 165 : 0/ 0/ 0

Load Information
Load Profile : Passed
Receive Utilization : 0%
Transmit Utilization : 0%
Channel Utilization : 34%
Attached Clients : 1 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 : 0 clients
RSSI -60 dBm : 0 clients
RSSI -52 dBm : 1 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 : 0 clients
SNR 35 dB : 0 clients
SNR 40 dB : 0 clients
SNR 45 dB : 1 clients

Nearby APs
AP 70bc.48ac.ee0f slot 1 : -44 dBm on (112, 40 MHz) (10.172.66.4)
AP 70bc.48ad.730f slot 1 : -54 dBm on (132, 40 MHz) (10.172.66.4)
AP 70bc.48ad.3c8f slot 1 : -58 dBm on ( 52, 40 MHz) (10.172.66.4)
AP 70bc.48ac.d68f slot 1 : -61 dBm on (149, 40 MHz) (10.172.66.4)
AP 70bc.48ad.33ef slot 1 : -73 dBm on (132, 40 MHz) (10.172.66.4)
AP 70bc.48ac.ce4f slot 1 : -76 dBm on ( 52, 40 MHz) (10.172.66.4)
AP 70bc.48ac.e18f slot 1 : -81 dBm on (100, 40 MHz) (10.172.66.4)

Radar Information
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 : 7177133 seconds ago

Channel Assignment Information via DCA
Current Channel Average Energy : -84 dBm
Previous Channel Average Energy : -84 dBm
Channel Change Count : 0
Last Channel Change Time : 04/26/2025 11:37:28
Recommended Best Channel : 161

RF Parameter Recommendations
Power Level : 4
RTS/CTS Threshold : 2347
Fragmentation Threshold : 2346
Antenna Pattern : 0

Persistent Interference Devices
Class Type Channel DC (%%) RSSI (dBm) Last Update Time
------------------------- ------- ------ --------- ----------------

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Fri, 18 Jul 2025 19:56:18 GMT

show ap name <AP with issue> tag detail <<- share this also

MHM

Re: DCA leaving APs on channels with over 40 percent utilization.

rhallan — Fri, 18 Jul 2025 21:06:42 GMT

show ap name xxxx tag detail
AP Name : xxxxx
AP Mac : xxxxx

Tag Type Tag Name
-----------------------------
Policy Tag xx_PT_Campus
RF Tag TP_Inside_RFT
Site Tag xx_ST_Campus

Policy tag mapping
------------------
WLAN Profile Name Policy Name VLAN Flex Central Switching IPv4 ACL IPv6 ACL
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
xx_Corp xx_PP_Corp data ENABLED Not Configured Not Configured
xx_Guest1 xx_PP_Guest1 quarantine ENABLED Not Configured Not Configured

Site tag mapping
----------------
Flex Profile : default-flex-profile
AP Profile : xx_AP_Campus
Local-site : Yes

RF tag mapping
--------------
6ghz RF Policy : default-rf-profile-6ghz
5ghz RF Policy : TP_a
2.4ghz RF Policy : TP_b
2.4ghz slot 0 Radio Policy : default-radio-profile
5ghz slot 1 Radio Policy : default-radio-profile
5ghz slot 2 Radio Policy : default-radio-profile
6ghz slot 2 Radio Policy : default-radio-profile
6ghz slot 3 Radio Policy : default-radio-profile

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Fri, 18 Jul 2025 21:53:31 GMT

Now you use dual band and rf profile

5ghz RF Policy : TP_a
2.4ghz RF Policy : TP_b

Not defualt' so are you sure DCA is enable for these profiles?

MHM

Re: DCA leaving APs on channels with over 40 percent utilization.

rhallan — Fri, 18 Jul 2025 22:24:06 GMT

The 2.4 GHz has a profile but all 2.4 GHz radios are shut off as those channels were not even usable due to interference. Only 5 GHz is in use. In GUI the DCA settings are under Configuration>Radio Configuration > RRM and it is setup to Automatic with medium sensitivity and EDRRM on. There is not really a enable DCA under these profiles TP_a. There is a RRM tab in the TP_a with setting like Channel Width, Avoid Foreign AP Interference , channel selection etc. and these are set up same as RRM. Also when you run CLI show ap name xxxxxxx auto-rf dot11 5ghz we see " Channel Assignment Information via DCA
Current Channel Average Energy : -84 dBm
Previous Channel Average Energy : -84 dBm
Channel Change Count : 0
Last Channel Change Time : 04/26/2025 11:37:28
Recommended Best Channel : 161

So I think DCA is running.

Question : So with the information you asked me to provide what are you looking for ? Do you know if there is a command or way to display the cost metric as this is what is used to trigger channel changes ?

Thanks for taking the time provide your input.

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Sat, 19 Jul 2025 01:07:15 GMT

set platform software trace wncd chassis active r0 radio-history-channel info

show logging profile wireless internal [to-file <file-name>]

Above debug you can use to see channel change

Note:- in ios xe of 9800 debug command is change with set plat

Channel is not change it same 84 dBm

But the rf utilize you use 80% as I remember default value is 50% not 80%.

Check rf profile general tab change utilize lower it and check if AP start auto change channel.

MHM

Re: DCA leaving APs on channels with over 40 percent utilization.

rhallan — Sat, 19 Jul 2025 02:03:00 GMT

The 80 % you refer to is for traps i.e. send alert when utilization is over 80% . It will not actually change the channel on the AP.

Re: DCA leaving APs on channels with over 40 percent utilization.

Rich R — Sat, 19 Jul 2025 21:33:48 GMT

The last white paper on DCA was written for AireOS 8.3: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_RRM_White_Paper/dca.html but the same basic principles still apply.

You can also check the config guide https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-15/config-guide/b_wl_17_15_cg/m_rrm_c9800.html for some info.

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Sun, 20 Jul 2025 14:31:24 GMT

You ask me what I looking for in show' this value I look for'

If channel not utilize above specific threshold value then it will not change.

Why you are thinking 80% for trap not for change ?

MHM

Re: DCA leaving APs on channels with over 40 percent utilization.

rhallan — Mon, 21 Jul 2025 15:48:22 GMT

Thanks for the replay. Please see attached picture. The heading say "Profile Threshold for Traps". Where do you see it is threshold to channel change ? Maybe share a picture or command to change the threshold for channel change. Thanks.

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Sun, 27 Jul 2025 21:01:13 GMT

I search way to config channel utilize throushold' there is no such option we can config

But I found workaround

show ap auto-rf 24ghz <<- run this command

Then channel it have high noice higg utilization we can exclude it from DCA

Check this workaround

MHM

Re: DCA leaving APs on channels with over 40 percent utilization.

rhallan — Mon, 28 Jul 2025 14:32:13 GMT

Great minds thing alike 🙂 I was thinking same as you on this point.

Before I go there I have changed the DCA sensitivity form Medium to High to see if it helps and changes the channels to quitter channels.

I also got a senior Cisco Engineer looking into the issue and once I get his input I will share with the community.

Thanks for you input.

Re: DCA leaving APs on channels with over 40 percent utilization.

MHM Cisco World — Mon, 28 Jul 2025 14:45:19 GMT

Friend

You are so welcome

Please update me if you get good solution

Have a nice day

MHM