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For the ath9k Wi-Fi driver, I wonder if there is a way to get the number of subframes that are aggregated in an A-MPDU before each transmission. Is there a way that I can fix the number of aggregated subframes?

Also, I use iw (iw 4.1) to display information about the Wi-Fi link. I notice that "expected throughput" is provided. Since I'm using ath9k, I assume that the value of the expected throughput is calculated somewhere in ath9k. Does anyone know how is the expected throughput calculated in ath9k?

Thanks a lot!

I do not think you will see "expected throughput" on an interface adapter  (there is a difference in "data-rate" and "throughput", we teach that in the CWNA training and do several labs showing the differences between the two and the optimizations like you mentioned "A-MPDU", "A-MSDU" and the other parameters that come along using IEEE 802.11n or IEEE 802.11ac.

Danaher/FlukeNetworks/AirMagnet, now recently taken over by Netscout.  This AirMagnet WiFi Analyser tool has a calculator built-in to visualise very well the impacted throughput on a WiFi network by enabling / disabling the IEEE 802.11n  or 802.11ac parameters  (the A-MPDU, A-MSDU, BAR, RIFS, etc.).

The AirMagnet Enterprise Solutions also has it built-in, by using the WiFi-Analyser function of the Sensor  (which is basically the same software as the laptop version). Only AME has currently only visualisation support for IEEE 802.11n.

The AirMagnet Poster "802.11n Primer" and equivalent PDF document has pictures which this visualisation, which you also can see in the CWNA-106 training material (handouts / slides) in Chapter 11 covering Thoughtputs benefits for 300 Mbps and 600 Mbps, but as mentioned with the calculator you can now also do all the way up to the IEEE 802.11ac  - 8 Spatial streams and MCS 9  visualisations.

802.11n (see page 6 of PDF, "page 7 in Adobe" MAC Layer Enhancements) -- http://www.airwisecommunity.com/assets/documents/AM_11n_Reference.pdf

(I am not to sure if you can read the  "real throughput" from the adapter level, including the "IFS", "pre-amble", "payload", "ACK").

RE: to get the number of subframes that are aggregated in an A-MPDU before each transmission. Is there a way that I can fix the number of aggregated subframes?

>>  I am not sure if it is defined in the IEEE 802.11-2012 or IEEE 802.11ac standard if a max. can be defined, maybe you can look into these standards?

>> (digging through 2700+ pages which are very technical in description).

>> or maybe someone else at the forum knows it by head ?

Ronald