Expected throughput in iwinfo assoclist

Installing and Using OpenWrt
1

Hello Folks,
I am trying to gain some understanding on how to interpret the "expected throughput" (ET) and the TX, RX rate from the iwinfo assoclist output.

In my AP, I see below:

xx:xx:xx:xx:xx:xx  -44 dBm / -95 dBm (SNR 51)  800 ms ago
	RX: 57.8 MBit/s, MCS 5, 20MHz                 268463 Pkts.
	TX: 72.2 MBit/s, MCS 7, 20MHz                  24998 Pkts.
	expected throughput: 34.9 MBit/s

ET, RX, TX are all in MBits/s. Why is ET lower than RX and TX ? The meaning of expected throughput completely change for me based on this data.

Can someone explain how to read the above output ?
Also, I believe that RX still means RX at AP side, not at client ? Same for TX.

Thanks in advance.

2

I'm just guessing, but when I've looked at this I assumed the "expected throughput" was an estimate based on theoretical max (which would be based on the mode+freq+channel width) with the signal-to-noise ratio taken into account. When SNR gets better up, ET goes up...

I too would love to know how it all ties together.

3

Expected throughput is the calculation of the average Rx+Tx+SNR+Overheads+Frame Aggregation, etc. and will always be dynamic because wireless is dynamic

You can expect nearly 35-50% loss of total Rx+Tx throughput for general WiFi rates depending mostly on SNR. Hope that helps.

Correct
RX: { AP } <---- [ Client ]
TX: { AP } ----> [ Client ]

Hope that helps

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4

@mindwolf Thanks. I think I got some clarity on it, but still not able to define my network throughput for the given client in plain english.
If you don't mind, given the same above information, how would you rate the network in terms of RX, TX rate for the specific client ? (Assuming the assoclist data do not vary much)

5

SNR= Excellent
Throughout=Very normal for 2GHz

Try picking a channel with the least amount of other ap's on it while still maintaining a good -SNR.

Channel Score = (Sum of Signal Strengths on Channel / Number of Networks on Channel) - (5 * Number of Networks on Channel) - (10 * Number of Overlapping Networks)
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