wifi data rate

asked 2022-01-26 17:25:53 +0000

Horst gravatar image

Hi. I use wireshark at win10 in combination with Acrylic Suite and ASUS USB-AC68. I capture air interface between router and mobile phone during iperf connection. Via iperf I can see a bandwidth of about 300Mbit/s. If I check the wireshark airtrace the <tx rate=""> max. is 156 (VHT / channel 36 / 20 MHz / MCS8 / 2 spatial streams).

Why there is this huge gap in bandwith between iperf and wireshark air-sniff? Is there any misinterpretation of wireshark? I'm using wireshark 3.4.9

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Are you sure you are capturing all the traffic in the stream?

Bob Jones gravatar imageBob Jones ( 2022-01-27 14:30:22 +0000 )edit

I'm not sure how to understand the question? Is there any chance to verify it if all data of the stream is captured?

Horst gravatar imageHorst ( 2022-01-27 16:26:05 +0000 )edit

Maybe I need to add the router is using a 80MHz channel. 80MHz is also configured by selecting the sniffer in wireshark.

Horst gravatar imageHorst ( 2022-01-27 17:14:43 +0000 )edit

Under Expert Details <analyse experteninformation=""> I have seen 25% of the packages get a warning about <data rate="" invalid="">.

Horst gravatar imageHorst ( 2022-01-28 10:55:39 +0000 )edit

One way to tell is from visual inspection - if you look at the first screenshot in the answer here, that would be one clue. Another clue is to verify via timing/size analysis that the traffic you see is consistent with what you expect. In this case, say iperf is run with simple options of just client and server, so that one of the hosts will send large packets to the other, very quickly. It is easy to verify the direction, rate, and relative size with a wired capture, then check on the wireless side to see if this is observed. Even if wireless traffic stream is encrypted, MAC address, frame length, and timing will be available. What is the datarate of these large frames moving from one host to the other, very rapidly? That would represent the iperf data moving and the comparison you need.

Bob Jones gravatar imageBob Jones ( 2022-01-28 11:05:54 +0000 )edit