I plugged into ethernet (as wifi w/captive portal does not work for me). I think clearnet worked but I have no interest in that. Egress Tor traffic was blocked and so was VPN. I’m not interested in editing all my scripts and configs to use clearnet, so the library’s internet is useless to me (unless I bother to try a tor bridge).
I was packing my laptop and a librarian spotted me unplugging my ethernet cable and approached me with big wide open eyes and pannicked angry voice (as if to be addressing a child that did something naughty), and said “you can’t do that!”
I have a lot of reasons for favoring ethernet, like not carrying a mobile phone that can facilitate the SMS verify that the library’s captive portal imposes, not to mention I’m not eager to share my mobile number willy nilly. The reason I actually gave her was that that I run a free software based system and the wifi drivers or firmware are proprietary so my wifi card doesn’t work¹. She was also worried that I was stealing an ethernet cable and I had to explain that I carry an ethernet cable with me, which she struggled to believe for a moment. When I said it didn’t work, she was like “good, I’m not surprised”, or something like that.
¹ In reality, I have whatever proprietary garbage my wifi NIC needs, but have a principled objection to a service financed by public money forcing people to install and execute proprietary non-free software on their own hardware. But there’s little hope for getting through to a librarian in the situation at hand, whereby I might as well have been caught disassembling their PCs.
Meh. So my point of view is that qos for Internet is better done at layer 3. Layer 2 qos has its place, but layer 3 is going to let you prioritise services better.
Moreso, if you do it at layer 3 you don’t need to worry about people using ethernet. Every person using ethernet is one less using the extremely finite resources WiFi has. Every active station puts a load on WiFi, less so with the latest versions but they still exhibit a lot of the same problems that mean many workstations can kill WiFi performance.
If you setup your network right (you can actually, although I’ve not seen it too often, setup guests networks on ethernet before WiFi, such that stations cannot see eachother directly) there’s no reason at all to fear ethernet.