Cisco CleanAir, available on Cisco AP 3700, 2700 and 2600 models, have spectrum analysis capability built right in to the radio hardware. While a CleanAir AP is busy operating its normal basic service sets (BSSs) on a channel, it can also monitor RF energy on that channel, analyze the data, and report specific information about any interfering devices - all without interrupting normal WLAN operation. This is all done with the Spectrum Analysis Engine (SAgE) chipset, operating in parallel with the normal 802.11 Wi-Fi chipset in the AP. The SAgE is always on and scans through the frequency range at a high resolution once per second. The high-resolution bandwidth enables the SAgE to identify interference sources with a high degree of accuracy.
Anything that the AP receives and recognizes as an 802.11 frame is processed normally by the split MAC architecture. Other signals that cannot be demodulated according to any known modulation and coding scheme must be coming from a non-802.11 source. That signal information is processed by the spectrum analysis hardware in the AP.
The spectrum information from every AP is sent up to the corresponding wireless LAN controller (WLC), where it can be collected and processed. If an interference source is received by more than one AP, the controller can usually correlate the data and realize that a single source is involved and not several different ones. WLCs can also pass interference reports to a Mobility Services Engine (MSE) to determine an interference source's location and display it on a Prime Infrastructure map. With CleanAir, interference can be automatically detected and identified, and its source located - which should make your job easier!
Beyond that, a Cisco unified wireless network can even react to wireless interference automatically. Recall that the RRM process is responsible for working out a channel reuse plan and assigning APs to use specific channels in a band - all on a periodic basis. Event-driven RRM can react to interference immediately, without waiting for the next scheduled RRM iteration, so that an AP can be moved to a different channel to escape the interference.
Enabling CleanAir
CleanAir operates on each band independently. You can enable or disable it globally for all APs (2600, 2700 and 3700 series) on a controller (image 7.0 and above) by selecting Wireless > 802.11a/n or 802.11b/g/n > CleanAir and using the CleanAir check box. By default, CleanAir is disabled globally on a controller.
By default, APs will report the interference types listed below to their respective controller. You can change the behavior on which the AP will report an interference by selecting a type and moving it to the Interferences to Ignore or Interferences to Detect list. You can also select which types will generate an SNMP trap from the controller when they are detected. Otherwise, any types not selected will not be reported.
Tip: An AP must be configured for either local or monitor mode before it can generate CleanAir interference reports. Reporting is not possible in the Spectrum Expert Connect (SE-Connect) mode.
As interference sources are detected and classified according to interference type, the AP also measures the received signal strength indicator (RSSI) and the duty cycle of the interferer. The duty cycle is the percentage of time the source is transmitting on the channel, which indicates its persistence or how much of the airtime the interferer is consuming. The AP combines the RSSI and duty cycle into a severity index value. Severity ranges from 0 (not severe) to 100 (very severe). Interference with a high severity rating can render a channel unusable.
Interference detection reports sent to a controller include the AP name, interference type, affected channel, time stamp, severity, duty cycle, and RSSI. The controller then tries to determine whether the same interference source is involved in reports coming from multiple APs. If so, the source is uniquely identified by assigning it a cluster ID. A cluster ID is actually a pseudo-MAC address that represents the non-802.11 device with a familiar wireless identifier.
You can display a list of interference detection reports on a controller by selecting Monitor > CleanAir > 802.11a/n/ac or 802.11b/g/n > Interference Devices.
In my wireless lab, I've used a couple of iPhones with Bluetooth enabled in order to generate some noise so that my CleanAir-enabled AP (AIR-CAP2602I) could detect it. You configure CleanAir settings on each radio (a/n/ac and b/g/n) by going to Wireless > 802.11 > CleanAir > tick Enabled > Apply.
I didn't see any interfering Bluetooth device at first, so I moved (to the right) the Bluetooth Link under Trap Configurations > Trap on these types > click Apply.
Enable Event Driven Radio Resource Management (EDRRM) on
each radio under Wireless > 802.11 > RRM > DCA > tick Enabled under
EDRRM > Apply. You can set the threshold to Low (AQI 35), Medium (AQI 50),
or High (AQI 60).
Below are some useful WLC CLI commands for troubleshooting CleanAir.
(Cisco Controller) >show 802.11?
802.11a 802.11b 802.11h
(Cisco Controller) >show 802.11a ?
cleanair Display 802.11a cleanair information.
cu-metrics Display AP channel utilization metrics
l2roam Display 80211a l2roam information.
media-stream Display Media Stream configurations for 802.11 5G and 2.4G band
extended Display 802.11a/b radio extended configurations
(Cisco Controller) >show 802.11a cleanair ?
air-quality Display 802.11a air quality information.
config Display 802.11a cleanair configuration.
device Display 802.11a cleanair interfering devices information.
(Cisco Controller) >show 802.11a cleanair config
Clean Air Solution............................... Enabled
Air Quality Settings:
Air Quality Reporting........................ Enabled
Air Quality Reporting Period (min)........... 15
Air Quality Alarms........................... Enabled
Air Quality Alarm Threshold................ 35
Unclassified Interference.................. Disabled
Unclassified Severity Threshold............ 20
Interference Device Settings:
Interference Device Reporting................ Enabled
Interference Device Types:
TDD Transmitter.......................... Enabled
Jammer................................... Enabled
Continuous Transmitter................... Enabled
DECT-like Phone.......................... Enabled
Video Camera............................. Enabled
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Enabled
Canopy................................... Enabled
WiMax Mobile............................. Enabled
--More-- or (q)uit
WiMax Fixed.............................. Enabled
Interference Device Alarms................... Enabled
Interference Device Types Triggering Alarms:
TDD Transmitter.......................... Disabled
Jammer................................... Enabled
Continuous Transmitter................... Disabled
DECT-like Phone.......................... Disabled
Video Camera............................. Disabled
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Disabled
Canopy................................... Disabled
WiMax Mobile............................. Disabled
WiMax Fixed.............................. Disabled
Additional Clean Air Settings:
CleanAir ED-RRM State........................ Enabled
CleanAir ED-RRM Sensitivity.................. Medium
CleanAir ED-RRM Custom Threshold............. 50
CleanAir Persistent Devices state............ Disabled
CleanAir Persistent Device Propagation....... Disabled
(Cisco Controller) >show 802.11b cleanair config
Clean Air Solution............................... Enabled
Air Quality Settings:
Air Quality Reporting........................ Enabled
Air Quality Reporting Period (min)........... 15
Air Quality Alarms........................... Enabled
Air Quality Alarm Threshold................ 35
Unclassified Interference.................. Disabled
Unclassified Severity Threshold............ 20
Interference Device Settings:
Interference Device Reporting................ Enabled
Interference Device Types:
Bluetooth Link........................... Enabled
Microwave Oven........................... Enabled
802.11 FH................................ Enabled
Bluetooth Discovery...................... Enabled
TDD Transmitter.......................... Enabled
Jammer................................... Enabled
Continuous Transmitter................... Enabled
DECT-like Phone.......................... Enabled
Video Camera............................. Enabled
802.15.4................................. Enabled
--More-- or (q)uit
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Enabled
Canopy................................... Enabled
Microsoft Device......................... Enabled
WiMax Mobile............................. Enabled
WiMax Fixed.............................. Enabled
BLE Beacon............................... Enabled
Interference Device Alarms................... Enabled
Interference Device Types Triggering Alarms:
Bluetooth Link........................... Disabled
Microwave Oven........................... Disabled
802.11 FH................................ Disabled
Bluetooth Discovery...................... Disabled
TDD Transmitter.......................... Disabled
Jammer................................... Enabled
Continuous Transmitter................... Disabled
DECT-like Phone.......................... Disabled
Video Camera............................. Disabled
802.15.4................................. Disabled
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Disabled
--More-- or (q)uit
Canopy................................... Disabled
Microsoft Device......................... Disabled
WiMax Mobile............................. Disabled
WiMax Fixed.............................. Disabled
BLE Beacon............................... Disabled
Additional Clean Air Settings:
CleanAir ED-RRM State........................ Enabled
CleanAir ED-RRM Sensitivity.................. Medium
CleanAir ED-RRM Custom Threshold............. 50
CleanAir Persistent Devices state............ Disabled
CleanAir Persistent Device Propagation....... Disabled
(Cisco Controller) >show 802.11b cleanair ?
air-quality Display 802.11b air quality information.
config Display 802.11b cleanair configuration.
device Display 802.11b cleanair interfering devices information.
(Cisco Controller) >show 802.11b cleanair air-quality
Incorrect usage. Use 'show 802.11b cleanair air-quality ?' to see valid options.
(Cisco Controller) >show 802.11b cleanair air-quality ?
<Cisco AP> Enter Cisco AP name
summary Display a summary of 802.11b air quality.
worst Display information for the 802.11b radio with the worst air quality.
(Cisco Controller) >show 802.11b cleanair air-quality summary
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
(Cisco Controller) >show 802.11b cleanair air-quality worst
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
(Cisco Controller) >show 802.11b cleanair device ?
type Display 802.11b interference information for the given device type in 2.4 GHz.
ap Display 802.11b interference devices information for the given AP for 2.4 GHz.
(Cisco Controller) >show 802.11b cleanair device type ?
bt-link Display 802.11b bluetooth-link devices information.
bt-discovery Display 802.11b bluetooth-discovery devices information.
ble-beacon Display 802.11b BLE Beacon devices information.
mw-oven Display 802.11b microwave oven devices information.
802.11-fh Display 802.11b frequency-hopper devices information.
802.15.4 Display 802.11b 802.15.4 devices information.
tdd-tx Display 802.11b tdd-transmitter devices information.
jammer Display 802.11b jammer devices information.
cont-tx Display 802.11b continuous-transmitter devices information.
dect-like Display 802.11b dect-like phone devices information.
video Display 802.11b video devices information.
802.11-inv Display 802.11b WiFi inverted devices information.
802.11-nonstd Display 802.11b WiFi non-standard devices information.
superag Display 802.11b superag devices information.
canopy Display 802.11b canopy devices information.
wimax-mobile Display 802.11b WiMax mobile devices information.
wimax-fixed Display 802.11b WiMax fixed devices information.
msft-xbox Display 802.11b Proprietary Microsoft device information.
(Cisco Controller) >show 802.11b cleanair device type bt-discovery
DC = Duty Cycle (%)
ISI = Interference Severity Index (1-Low Interference, 100-High Interference)
RSSI = Received Signal Strength Index (dBm)
DevID = Device ID
* indicates cluster center device
No ClusterID DevID Type AP Name ISI RSSI DC Channel
--- ------------------ ------ ------------- ------------------------ ---- ----- ---- ----------
1 * 03:49:80:00:00:07 0x1009 BT Discovery APf872.eaa6.e203 7 -27 1 1
(Cisco Controller) >show 802.11b cleanair device ap ?
<Cisco AP> Enter Cisco AP name
(Cisco Controller) >show 802.11b cleanair device ap APf872.eaa6.e203
DC = Duty Cycle (%)
ISI = Interference Severity Index (1-Low Interference, 100-High Interference)
RSSI = Received Signal Strength Index (dBm)
DevID = Device ID
No ClusterID DevID Type AP Name ISI RSSI DC Channel
--- ------------------ ------ ------------- ------------------------ ---- ----- ---- ----------
1 03:49:80:00:00:07 0x1009 BT Discovery APf872.eaa6.e203 7 -27 1 1
(Cisco Controller) >show 802.11b cleanair air-quality summary
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
(Cisco Controller) >show 802.11b cleanair air-quality worst
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
Anything that the AP receives and recognizes as an 802.11 frame is processed normally by the split MAC architecture. Other signals that cannot be demodulated according to any known modulation and coding scheme must be coming from a non-802.11 source. That signal information is processed by the spectrum analysis hardware in the AP.
The spectrum information from every AP is sent up to the corresponding wireless LAN controller (WLC), where it can be collected and processed. If an interference source is received by more than one AP, the controller can usually correlate the data and realize that a single source is involved and not several different ones. WLCs can also pass interference reports to a Mobility Services Engine (MSE) to determine an interference source's location and display it on a Prime Infrastructure map. With CleanAir, interference can be automatically detected and identified, and its source located - which should make your job easier!
Beyond that, a Cisco unified wireless network can even react to wireless interference automatically. Recall that the RRM process is responsible for working out a channel reuse plan and assigning APs to use specific channels in a band - all on a periodic basis. Event-driven RRM can react to interference immediately, without waiting for the next scheduled RRM iteration, so that an AP can be moved to a different channel to escape the interference.
Enabling CleanAir
CleanAir operates on each band independently. You can enable or disable it globally for all APs (2600, 2700 and 3700 series) on a controller (image 7.0 and above) by selecting Wireless > 802.11a/n or 802.11b/g/n > CleanAir and using the CleanAir check box. By default, CleanAir is disabled globally on a controller.
By default, APs will report the interference types listed below to their respective controller. You can change the behavior on which the AP will report an interference by selecting a type and moving it to the Interferences to Ignore or Interferences to Detect list. You can also select which types will generate an SNMP trap from the controller when they are detected. Otherwise, any types not selected will not be reported.
Tip: An AP must be configured for either local or monitor mode before it can generate CleanAir interference reports. Reporting is not possible in the Spectrum Expert Connect (SE-Connect) mode.
As interference sources are detected and classified according to interference type, the AP also measures the received signal strength indicator (RSSI) and the duty cycle of the interferer. The duty cycle is the percentage of time the source is transmitting on the channel, which indicates its persistence or how much of the airtime the interferer is consuming. The AP combines the RSSI and duty cycle into a severity index value. Severity ranges from 0 (not severe) to 100 (very severe). Interference with a high severity rating can render a channel unusable.
Interference detection reports sent to a controller include the AP name, interference type, affected channel, time stamp, severity, duty cycle, and RSSI. The controller then tries to determine whether the same interference source is involved in reports coming from multiple APs. If so, the source is uniquely identified by assigning it a cluster ID. A cluster ID is actually a pseudo-MAC address that represents the non-802.11 device with a familiar wireless identifier.
You can display a list of interference detection reports on a controller by selecting Monitor > CleanAir > 802.11a/n/ac or 802.11b/g/n > Interference Devices.
In my wireless lab, I've used a couple of iPhones with Bluetooth enabled in order to generate some noise so that my CleanAir-enabled AP (AIR-CAP2602I) could detect it. You configure CleanAir settings on each radio (a/n/ac and b/g/n) by going to Wireless > 802.11 > CleanAir > tick Enabled > Apply.
I didn't see any interfering Bluetooth device at first, so I moved (to the right) the Bluetooth Link under Trap Configurations > Trap on these types > click Apply.
To monitor go to Monitor > Cisco CleanAir > choose a 802.11
radio (a/n/ac or b/g/n) > Interference Device or Air Quality Report.
(Cisco Controller) >show 802.11?
802.11a 802.11b 802.11h
(Cisco Controller) >show 802.11a ?
cleanair Display 802.11a cleanair information.
cu-metrics Display AP channel utilization metrics
l2roam Display 80211a l2roam information.
media-stream Display Media Stream configurations for 802.11 5G and 2.4G band
extended Display 802.11a/b radio extended configurations
(Cisco Controller) >show 802.11a cleanair ?
air-quality Display 802.11a air quality information.
config Display 802.11a cleanair configuration.
device Display 802.11a cleanair interfering devices information.
(Cisco Controller) >show 802.11a cleanair config
Clean Air Solution............................... Enabled
Air Quality Settings:
Air Quality Reporting........................ Enabled
Air Quality Reporting Period (min)........... 15
Air Quality Alarms........................... Enabled
Air Quality Alarm Threshold................ 35
Unclassified Interference.................. Disabled
Unclassified Severity Threshold............ 20
Interference Device Settings:
Interference Device Reporting................ Enabled
Interference Device Types:
TDD Transmitter.......................... Enabled
Jammer................................... Enabled
Continuous Transmitter................... Enabled
DECT-like Phone.......................... Enabled
Video Camera............................. Enabled
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Enabled
Canopy................................... Enabled
WiMax Mobile............................. Enabled
--More-- or (q)uit
WiMax Fixed.............................. Enabled
Interference Device Alarms................... Enabled
Interference Device Types Triggering Alarms:
TDD Transmitter.......................... Disabled
Jammer................................... Enabled
Continuous Transmitter................... Disabled
DECT-like Phone.......................... Disabled
Video Camera............................. Disabled
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Disabled
Canopy................................... Disabled
WiMax Mobile............................. Disabled
WiMax Fixed.............................. Disabled
Additional Clean Air Settings:
CleanAir ED-RRM State........................ Enabled
CleanAir ED-RRM Sensitivity.................. Medium
CleanAir ED-RRM Custom Threshold............. 50
CleanAir Persistent Devices state............ Disabled
CleanAir Persistent Device Propagation....... Disabled
(Cisco Controller) >show 802.11b cleanair config
Clean Air Solution............................... Enabled
Air Quality Settings:
Air Quality Reporting........................ Enabled
Air Quality Reporting Period (min)........... 15
Air Quality Alarms........................... Enabled
Air Quality Alarm Threshold................ 35
Unclassified Interference.................. Disabled
Unclassified Severity Threshold............ 20
Interference Device Settings:
Interference Device Reporting................ Enabled
Interference Device Types:
Bluetooth Link........................... Enabled
Microwave Oven........................... Enabled
802.11 FH................................ Enabled
Bluetooth Discovery...................... Enabled
TDD Transmitter.......................... Enabled
Jammer................................... Enabled
Continuous Transmitter................... Enabled
DECT-like Phone.......................... Enabled
Video Camera............................. Enabled
802.15.4................................. Enabled
--More-- or (q)uit
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Enabled
Canopy................................... Enabled
Microsoft Device......................... Enabled
WiMax Mobile............................. Enabled
WiMax Fixed.............................. Enabled
BLE Beacon............................... Enabled
Interference Device Alarms................... Enabled
Interference Device Types Triggering Alarms:
Bluetooth Link........................... Disabled
Microwave Oven........................... Disabled
802.11 FH................................ Disabled
Bluetooth Discovery...................... Disabled
TDD Transmitter.......................... Disabled
Jammer................................... Enabled
Continuous Transmitter................... Disabled
DECT-like Phone.......................... Disabled
Video Camera............................. Disabled
802.15.4................................. Disabled
WiFi Inverted............................ Enabled
WiFi Invalid Channel..................... Enabled
SuperAG.................................. Disabled
--More-- or (q)uit
Canopy................................... Disabled
Microsoft Device......................... Disabled
WiMax Mobile............................. Disabled
WiMax Fixed.............................. Disabled
BLE Beacon............................... Disabled
Additional Clean Air Settings:
CleanAir ED-RRM State........................ Enabled
CleanAir ED-RRM Sensitivity.................. Medium
CleanAir ED-RRM Custom Threshold............. 50
CleanAir Persistent Devices state............ Disabled
CleanAir Persistent Device Propagation....... Disabled
(Cisco Controller) >show 802.11b cleanair ?
air-quality Display 802.11b air quality information.
config Display 802.11b cleanair configuration.
device Display 802.11b cleanair interfering devices information.
(Cisco Controller) >show 802.11b cleanair air-quality
Incorrect usage. Use 'show 802.11b cleanair air-quality ?' to see valid options.
(Cisco Controller) >show 802.11b cleanair air-quality ?
<Cisco AP> Enter Cisco AP name
summary Display a summary of 802.11b air quality.
worst Display information for the 802.11b radio with the worst air quality.
(Cisco Controller) >show 802.11b cleanair air-quality summary
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
(Cisco Controller) >show 802.11b cleanair air-quality worst
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
(Cisco Controller) >show 802.11b cleanair device ?
type Display 802.11b interference information for the given device type in 2.4 GHz.
ap Display 802.11b interference devices information for the given AP for 2.4 GHz.
(Cisco Controller) >show 802.11b cleanair device type ?
bt-link Display 802.11b bluetooth-link devices information.
bt-discovery Display 802.11b bluetooth-discovery devices information.
ble-beacon Display 802.11b BLE Beacon devices information.
mw-oven Display 802.11b microwave oven devices information.
802.11-fh Display 802.11b frequency-hopper devices information.
802.15.4 Display 802.11b 802.15.4 devices information.
tdd-tx Display 802.11b tdd-transmitter devices information.
jammer Display 802.11b jammer devices information.
cont-tx Display 802.11b continuous-transmitter devices information.
dect-like Display 802.11b dect-like phone devices information.
video Display 802.11b video devices information.
802.11-inv Display 802.11b WiFi inverted devices information.
802.11-nonstd Display 802.11b WiFi non-standard devices information.
superag Display 802.11b superag devices information.
canopy Display 802.11b canopy devices information.
wimax-mobile Display 802.11b WiMax mobile devices information.
wimax-fixed Display 802.11b WiMax fixed devices information.
msft-xbox Display 802.11b Proprietary Microsoft device information.
(Cisco Controller) >show 802.11b cleanair device type bt-discovery
DC = Duty Cycle (%)
ISI = Interference Severity Index (1-Low Interference, 100-High Interference)
RSSI = Received Signal Strength Index (dBm)
DevID = Device ID
* indicates cluster center device
No ClusterID DevID Type AP Name ISI RSSI DC Channel
--- ------------------ ------ ------------- ------------------------ ---- ----- ---- ----------
1 * 03:49:80:00:00:07 0x1009 BT Discovery APf872.eaa6.e203 7 -27 1 1
(Cisco Controller) >show 802.11b cleanair device ap ?
<Cisco AP> Enter Cisco AP name
(Cisco Controller) >show 802.11b cleanair device ap APf872.eaa6.e203
DC = Duty Cycle (%)
ISI = Interference Severity Index (1-Low Interference, 100-High Interference)
RSSI = Received Signal Strength Index (dBm)
DevID = Device ID
No ClusterID DevID Type AP Name ISI RSSI DC Channel
--- ------------------ ------ ------------- ------------------------ ---- ----- ---- ----------
1 03:49:80:00:00:07 0x1009 BT Discovery APf872.eaa6.e203 7 -27 1 1
(Cisco Controller) >show 802.11b cleanair air-quality summary
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
(Cisco Controller) >show 802.11b cleanair air-quality worst
AQ = Air Quality
DFS = Dynamic Frequency Selection
AP Name Channel Avg AQ Min AQ Interferers DFS
------------------ ------- ------ ------ ----------- ---
APf872.eaa6.e203 1 99 99 1
Thanks , Very helpful
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