Cisco Cisco Aironet 3500i Access Point Libro blanco
Copyright © 2010 Miercom
Cisco CleanAir Competitive
Page 9
Interference Classification
In addition to knowing the impact that other signaling devices have on a network, we need to
identify the location and source in order to remediate the problem. We evaluated Cisco CleanAir
technology with the Aironet 3500 Series and the Motorola AirDefense solution with the AP-
7131N access point and the M520 sensor. Both solutions classify sources of interference
whereas other vendors tested do not offer interference classification capabilities.
identify the location and source in order to remediate the problem. We evaluated Cisco CleanAir
technology with the Aironet 3500 Series and the Motorola AirDefense solution with the AP-
7131N access point and the M520 sensor. Both solutions classify sources of interference
whereas other vendors tested do not offer interference classification capabilities.
The Cisco Aironet 3500 Series access point has a built-in spectrum analyzer from a new custom
CleanAir ASIC in the AP which allows real-time network monitoring while providing WLAN
services to clients. The Motorola AP-7131N also provides spectrum analysis. The AP can
provide either WLAN services or can monitor the spectrum, but not both simultaneously.
Disabling an access point to provide interference monitoring can increase the load on other APs
and reduces network capacity. Since it is a standard Wi-Fi chipset, the resolution of its analysis
is limited. We observed a scanning resolution of 78 KHz for the Cisco CleanAir, and 5 MHz for
the Motorola. This offers as much as 64x the scanning resolution compared to Motorola.
CleanAir ASIC in the AP which allows real-time network monitoring while providing WLAN
services to clients. The Motorola AP-7131N also provides spectrum analysis. The AP can
provide either WLAN services or can monitor the spectrum, but not both simultaneously.
Disabling an access point to provide interference monitoring can increase the load on other APs
and reduces network capacity. Since it is a standard Wi-Fi chipset, the resolution of its analysis
is limited. We observed a scanning resolution of 78 KHz for the Cisco CleanAir, and 5 MHz for
the Motorola. This offers as much as 64x the scanning resolution compared to Motorola.
Cisco CleanAir also provides mapping via the WCS UI which allows it to pinpoint the physical
location of an interfering signal.
location of an interfering signal.
This is a screen shot of the Cisco WCS displaying the physical location of a video camera
interference source. The red circle centered around the device represents the interferer’s zone
of impact.
interference source. The red circle centered around the device represents the interferer’s zone
of impact.