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WAP371 packet capture questions



this is my first post to the forum. I recently bought a Cisco WAP371 to use as an 802.11ac packet capture device. I have it set up to operate on the 5GHz radio only with channel 48 as the primary channel and have selected 80 MHz channel width. There are no wireless clients associated with the WAP and I use my laptop connected to it via Ethernet to turn packet capture on and off.

I have been experimenting with capturing packets between my desktop computer which has a Netgear A6210 802.11ac client adapter and my home wireless router which is a Netgear R7000 running Asuswrt-Merlin firmware (also set up for channel 48 @80MHz channel width).

I download the captured trace files to my computer to examine with Wireshark.

For the most part it works well and as expected but I do have a few observations/questions that I would like to ask.

1. Even though I am on a 5GHz radio channel the information in the Radiotap header always shows, under channel flags, that it is operating in the 2GHz spectrum. The channel flag for 5GHz is always off. Any idea why?

2. Similarly, when looking at the captured 802.11 radio information the PHY type always shows 802.11g (6) - why not 802.11ac?

3. Most of the captured Management frames (e.g., Beacons, Probe Requests etc) appear as Malformed packets. It appears that the FCS field at the end of these packets is not treated as FCS but rather an extension of the management frame data - hence the malformation. Is this a known issue with the WAP371 packet capture? (In the radiotap flags section FCS at end is always false).

4. If I run a speedtest from my computer and capture the packets I never see a data packet with a Tx rate greater than 106Mb/s. The vast majority being 84Mb/s. However the results of the speedtest says I am getting >150Mb/s download. The WAP371 is situated close to my client adapter. Captured RSSI for the client is -37dBm and for the AP -46dBm. Noise level is -92dBm. There are no other AP's or clients on the channel. I would have expected to see faster Tx rates. Are there any known issues with the Tx rate capture? 

Thanks in advance for any guidance or insights anyone can give me.



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