Openwrt, why can the Internet slow down?

Question

Computer networks

A cable comes to me from the provider and enters the TP-Link TL-WR740N router on OpenWRT with Luci. Then, via Ethernet, it goes to a laptop, and via Wi-Fi it goes to an apple tablet and an Android phone.
What is the problem:
1. On a PC, articles in the browser often load extremely slowly, sometimes 10 seconds pass only until the download starts.
2. Video errors constantly pop up on the tablet in YouTube, sometimes you have to click on the video again ten times to start loading, but even this does not always help. If I turn off Wi-Fi - everything immediately loads quickly.
3. Even on the tablet, DNS errors ERR_NAME_NOT_RESOLVED often get out.
4. The phone very often disconnects from Wi-Fi itself, although it does not disappear, it is visible in the list with a strong signal (I didn’t understand this at all, the phone is smarter than me, damn it).
The main thing that I found on the Internet is to register DNS from OpenDNS. I did this in the router, but, as you can see, it did not help.
What might be causing this behavior? What other tests can I run to find out more information? Maybe post dmesg here?

Answer 1

Plug the provider's cable directly into the computer (MAC may have to be emulated). If problems remain - kick the provider. If the problems go away - change the router - it is quite possible that it does not hold your load.