CAKE w/ Adaptive Bandwidth [August 2022 to March 2024]

Thanks for the idea, I will definitely run some tool to measure OWDs during the meeting.

This post will be updated with the results.

Baseline without SQM at 20:14 PST (the meeting will be at 23:00 PST):

Speedtest: https://www.speedtest.net/result/14440296383 (but note that the ISP cheats and gives speedtest a very preferential treatment - so this only indicates what the radio channel is capable of)

Waveform bufferbloat: https://www.waveform.com/tools/bufferbloat?test-id=56f48ca0-427d-49fe-9587-8fb58d60644d

Note: after these measurements, the modem has been slightly repositioned (literally 2 cm closer to the wall) in hope to get a better uplink quality - unfortunately at the expense of downlink.

Baseline without SQM just before the meeting (22:57 PST):

Speedtest: https://www.speedtest.net/result/14441050030

Waveform bufferbloat: https://www.waveform.com/tools/bufferbloat?test-id=ef844441-a846-4060-b7fe-9e3484332aa5

Baseline with SQM set high enough just after the meeting (23:36 PST):

Speedtest: https://www.speedtest.net/result/14441225196

Waveform bufferbloat: https://www.waveform.com/tools/bufferbloat?test-id=64fef20f-b531-4057-aeb8-54fa2cb9d67a

Logs and configs used during the meeting: https://u.pcloud.link/publink/show?code=kZufOPVZw7Pt1fRuLuy6DUH5YV7VpjksN8bV (too large for the pastebin)

During the first part of the meeting, I tried to keep cake-autorate on, with the cake-autorate_config.lte.sh config that you can see in this folder. It worked for some time, then dropped to 200 kbps (and yes I have to keep the minimum that low, because during heavy rains it is sometimes that bad) and never recovered. The log is saved as cake-autorate.lte.log.bad. Bad, because Discord, at least inside Firefox, does not adapt to such low bandwidth.

During the second part of the meeting, the SQM has been restarted and reset to a high bandwidth limit that surely could not be hit (15000/15000 kbps). Then, cake-autorate was run with a config that never actually adjusts the rates, cake-autorate_config.lte.sh.new. The corresponding log is cake-autorate.lte.log. The second part of the meeting went OK-ish, but there was one complaint that my voice is choppy. Also this log has the two speedtests (speedtest.net + waveform bufferbloat) at the end recorded.

The OWDs have not been recorded properly, because I forgot to use mwan3 use lte. Sorry!

Also, the signal quality was monitored, and saved as hcsq.log. The columns are the timestamp, the constant string "LTE", and the four numbers (r1, r2, r3, r4) that "AT^HCSQ?" returns after it on a Huawei E3372s modem. Interpretation:

RSSI_dBm = -120 + r1 
RSRP_dBm = -140 + r2
SINR_dB = -20 + (r3 * 0.2)
RSRQ_dB = -19.5 + (r4 * 0.5)

I hope that this array of raw data would be of some use to determine how to deal with such bad links.

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