A customer has an existing wireless network with these components: - Cisco 9800 wireless controller high availability cluster - Cisco 9120 APs The customer asks an engineer to perform a post…

Identifying non-802.11 interferers on the 5 GHz band without a spectrum analyzer requires using the CleanAir RF ASIC embedded in Cisco APs and exporting the interferer list from the WLC.

Wireless Site Survey

Question

A customer has an existing wireless network with these components:

Cisco 9800 wireless controller high availability cluster
Cisco 9120 APs

The customer asks an engineer to perform a post wireless survey of the current network state that includes a list of any non-802.11 devices on the 5 GHz band. The engineer performs the survey by using an 802.11a/b/g/n/ac/ax WLAN adapter but did not use a spectrum analyzer. Which approach meets the requirements?

Options

ASet the WLAN adapter to monitor mode and perform the analysis by using 802.11b.
BSet the WLAN adapter to monitor mode and perform the analysis by using 802.11a.
CExport a list of 802.11b interferes using the WLC and the RF ASIC embedded in the APs.
DExport a list of 802.11a interferes using the WLC and the RF ASIC embedded in the APs.

Why each option

Identifying non-802.11 interferers on the 5 GHz band without a spectrum analyzer requires using the CleanAir RF ASIC embedded in Cisco APs and exporting the interferer list from the WLC.

ASet the WLAN adapter to monitor mode and perform the analysis by using 802.11b.

A WLAN adapter in monitor mode captures only 802.11 frames and cannot detect non-802.11 devices, and 802.11b operates on the 2.4 GHz band rather than the required 5 GHz band.

BSet the WLAN adapter to monitor mode and perform the analysis by using 802.11a.

A WLAN adapter in monitor mode is incapable of identifying non-802.11 interferers regardless of band, because it only decodes 802.11 protocol frames.

CExport a list of 802.11b interferes using the WLC and the RF ASIC embedded in the APs.

802.11b operates on the 2.4 GHz band, so exporting 802.11b interferers from the WLC would not surface non-802.11 devices on the 5 GHz band as required.

DExport a list of 802.11a interferes using the WLC and the RF ASIC embedded in the APs.

Concept tested: CleanAir RF ASIC detecting non-802.11 5 GHz interferers

Source: https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/cleanair.html

Topics

#CleanAir#RF ASIC#non-802.11 interference#post-deployment survey

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