[Networking] Jamatu1:
Like an increasing number of others I've 'cut the cord' and only use my mobile for internet access. I use USB tethering to share the data with my other devices through a router. I've done a few benchmarks to determine the USB tethering bandwidth and latency between my recently bought Oneplus 8 and it's tethered device. For testing purposes I connected it directly to my laptop and booted into Windows and Ubuntu. A few issues cropped up that I thought worth highlighting to determine what the underlying causes are, to see if there's anything that can be done to resolve them and to get results from others from there devices. Relatively high latencies were observed as were connectivity issues during high bandwidth throughput. Results as below

Latency (average of 100 pings, other devices added for comparison)

Oneplus8

Moto G6 Play (Android 9)

Samsung XCover3 (Android 5)

The latency results shows that

The Oneplus 8 has around 3-5 times higher latency than the older and significantly lower specced Samsung XCover3 and Moto G6 Play.

The windows latency timings are around twice that of the Unbuntu timings for the Oneplus, the OS type had a minimal effect on the XCover 3 and no influence on the G6

USB3 adds another 0.5ms to the round trip times in both directions over USB2 for windows but has no influence when used under Ubuntu

The response times from the mobile devices are generally slower than the response times from the laptop

Given the push for 5G for higher bandwidth and lower latencies (when SA 5G NR is implemented at least) it's a step backward to have increased latency times on the user equipment. This will add to the overall latency. I'm interested in seeing what latency times other people are getting over USB tethering not just for the Oneplus 8 but for other makes and models too.

Bandwidth (measured using iperf3 server on the laptop and client on the Oneplus via USB3 average of 10 seconds)

Download

Upload

The iperf tests caused stability issues on the Oneplus 8 whilst using USB3. The USB interface would often crash and reset (confirmed via crash log in logcat). No stability issues were identified using USB2 or WiFi. USB2 bandwidth was maxed out so figures not included in the results. Max Wifi speeds were around 550Mbit/s using 5Ghz WiFi 5. I don't have another Wifi 6 device to test with.

The bandwidth results shows that

There's stability issues using USB3 when pushing bandwidth to the limit

Both download and uploads were faster in Ubuntu

Windows needed two parallel streams to attain top speed whereas in Ubuntu one was sufficient

In usage terms max download speeds (from the Oneplus to the laptop) averaged at 652Mbit/s and and upload speed max averaged out at 947Mbit/s. I don't know if this is a hardware or driver/software limit.

With 5G already hitting over 1Gbit/s the tethering bandwidth over USB3 is now the limiting factor. There's plenty of bandwidth available on the underlying USB3 protocol so its up to manufacturers to push the envelope. It's worth mentioning that Oneplus are still one of only a small selection of manufacturers that have implemented USB3 so this is worth commending. Most are still releasing phones restricted to USB2 speeds. I don't have another mobile with USB3 to test with for comparison. As with the latency findings I'm interested in seeing what results others are getting for USB3 tethering for both the Oneplus 8 and other devices.

App used for testing on the mobiles was Hurricane Electrics 'he.net Network Tools'