What size was the upload, how long did it take? I’d like to test here, and see what happens on my setup. I have Virgin Media cable, 200 down / 20 up.

Really random guess is it is something to do with the free Plusnet router.

very simple test,
run a ping in the background, then run a tbb speedtest
my fttc 45mbit line results, you can see idle, single download, multiple stream, upload, then idle again

PS C:\WINDOWS\system32> ping bbc.co.uk -4 -n 100

Pinging bbc.co.uk [151.101.192.81] with 32 bytes of data:
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=45ms TTL=57
Reply from 151.101.192.81: bytes=32 time=47ms TTL=57
Reply from 151.101.192.81: bytes=32 time=46ms TTL=57
Reply from 151.101.192.81: bytes=32 time=44ms TTL=57
Reply from 151.101.192.81: bytes=32 time=46ms TTL=57
Reply from 151.101.192.81: bytes=32 time=45ms TTL=57
Reply from 151.101.192.81: bytes=32 time=47ms TTL=57
Reply from 151.101.192.81: bytes=32 time=47ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=74ms TTL=57
Reply from 151.101.192.81: bytes=32 time=77ms TTL=57
Reply from 151.101.192.81: bytes=32 time=90ms TTL=57
Reply from 151.101.192.81: bytes=32 time=90ms TTL=57
Reply from 151.101.192.81: bytes=32 time=89ms TTL=57
Reply from 151.101.192.81: bytes=32 time=91ms TTL=57
Reply from 151.101.192.81: bytes=32 time=89ms TTL=57
Reply from 151.101.192.81: bytes=32 time=86ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=115ms TTL=57
Reply from 151.101.192.81: bytes=32 time=240ms TTL=57
Reply from 151.101.192.81: bytes=32 time=196ms TTL=57
Reply from 151.101.192.81: bytes=32 time=235ms TTL=57
Reply from 151.101.192.81: bytes=32 time=180ms TTL=57
Reply from 151.101.192.81: bytes=32 time=225ms TTL=57
Reply from 151.101.192.81: bytes=32 time=265ms TTL=57
Reply from 151.101.192.81: bytes=32 time=213ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57
Reply from 151.101.192.81: bytes=32 time=5ms TTL=57

edit speed test result
https://www.thinkbroadband.com/speedtest/15901705011...

Edited by ggremlin (Fri 22-May-20 19:19:25)

I did your test, the highest my latency went to was 133ms for a couple of packets. My normal latency is 12ms, and there were 5 or so pings of 85ms.

However that's all happening on the same machine - so the sharing is handled by Windows (in my case).

I need a test where I upload something massive, and then try a video call on another machine, to see if the router handles sharing in a better way than the OP's.

I used the 1 GB test file that I downloaded from this site. I did not let the upload complete. Incidentally, I am not using the Plusnet supplied router, but a TP-Link one.

In reply to a post by tboorman:

I used the 1 GB test file that I downloaded from this site. I did not let the upload complete. Incidentally, I am not using the Plusnet supplied router, but a TP-Link one.

Where did you upload to? I need somewhere that can saturate my upload speed, and then I can try and run a video call on another machine to see if it breaks up.

All routers should do the same in theory, unless there is a bug in their firmware.

I uploaded to https://www.azurespeed.com/Azure/UploadLargeFile.

Useful, thank you!

Ok, I have combined two of the 1GB files into a 2GB file, and set an upload going to the Azure test (using UK South region). My desktop is wired ethernet to my Asus router, and it started with a 20 Mbps upload speed, visible on Win10 task manager.

I then made a Facetime call from my iPad (on WiFi) to my iPhone (on 4G), which worked fine. I also tried a constant ping to Google's DNS, 8.8.8.8 and no loss in packets, and responses of 17ms.

The upload is still going, but has slowed down, my task manager showing only 1 Mbps in use, so I've switched Azure region to the US. My ping times are now 30 to 50ms. And its stopped uploading at 7% again.

So I've cleared some space from a VPS I have, and uploading there using WinSCP. This is saturating my uplink, hoping to see something on the BQM shortly.

The upload speed has now slowed to 19 Mbps, as my mate has called me on Facetime!

So no problems here .

Edited by jchamier (Sat 23-May-20 13:11:48)

BQM shows a small peak, and no packet loss.

Sounds like classic bufferbloat to me. Limiting egress rate to slightly below line rate using whatever QoS or shaper options are available in your router would likely help.

Is this behaviour common, yes. Should it be like this, no. 'Latency under load' is an important metric for interactive response/latency sensitive traffic.

Thanks for testing this out. It looks like my issue was down to the TP-Link router - I have changed it for an AVM FRITZ!Box, and the ping times are a lot better during an upload, although I am still seeing some packet loss:

Ping statistics for 1.1.1.1:
Packets: Sent = 91, Received = 84, Lost = 7 (7% loss),
Approximate round trip times in milli-seconds:
Minimum = 14ms, Maximum = 188ms, Average = 35ms