Hi Michael, > On Jun 16, 2020, at 12:18, Michael Yartys via Make-wifi-fast wrote: > > > From: Michael Yartys > Subject: Higher latency on upload under poor signal conditions > Date: June 16, 2020 at 12:18:38 GMT+2 > To: "make-wifi-fast@lists.bufferbloat.net" > Reply-To: Michael Yartys > > > Hi > > I decided to run some 8-stream TCP tests at the edge of the range of my WiFi network, and I noticed that I get higher latency when I run an upload compared to a download. The latency when downloading is pretty steady at right above 30 ms, and when I run the upload it hovers around 80-100 ms. I think I know why this happens, but I would like to read the opinion of the mailing list. My naive guess would be that air-time fairness by the AP only directly affects the AP's own transmissions, the stations will in all likelihood not have an fq_codel instance in its wifi-stack (I could be wrong, but I do not believe that the 7260ac intel card actually uses airtime fairness yet/at all). So the 80-100ms might just come from the default wifi parameters which typically are adjusted for peak thoughput instead of a balanced throughput latency under load set-point. Then again that is my _guess_, so Kruger-Dunning might apply. Best Regards Sebastian > > My test setup is a NETGEAR R7800 running OpenWrt with fq_codel'd WiFi and a laptop with an Intel 7260 ac wireless card. The laptop reports an average signal strength of about -77 dBm, while the router has a much harder time hearing the laptop at -98 dBm signal strength with a noise floor of -109 dBm. > > I suspect this extra latency is due to buffering because the laptop has to retransmit a lot of frames due to how poorly the router hears it. Is this correct? > > The associated flent files are attached. > > Michael