What protocol does the device use to determine that the Wi-Fi point (to which it is connected) has disappeared?

Question

Computer networks

For example, if you raise a Wi-Fi point on an Android phone (for example, the phone itself is connected to nothing, so there will be no Internet access, but it doesn’t seem to matter), and connect a neighboring laptop to this point, and then turn it off on the phone point, then on the laptop in a few seconds it will disappear.
It turns out that the laptop somehow monitors the availability of the point as a "server" (monitors by the keep-alive principle in TCP, or something like that), regardless of TCP / UDP and higher.
So - what is the name of the protocol by which these messages are sent?
I say right away - the question is purely for general development. I'm not going to track through this break in my client-server application - I know that it would be wrong.

Answer 1

beacon frame