How does a router work?

Question

WiFi

When we connect to a wifi network, the computer sends a request to the router, and it either denies access or accepts our PC and gives it an ip, the question is, after the connection itself, during operation, the computer and the router constantly exchange information (about the state of the network, etc. .e), how does this exchange proceed? The router periodically sends data to the computer. that he is online and all the rules, and when disconnected, sends the appropriate signal, or does the computer constantly send signals to the router and receive a response from it? And yet, how can you see these packets that our PC receives when communicating with the router, when the connection is broken, or just constant messages about the state of the network, I understand that they are encrypted and all that, but nevertheless.

Answer 1

read about the OSI model - it's about networks in general.
via wifi: the router regularly sends bacon packets with the name of the network (this is how the network appears in the list of available ones). there is also active scanning, when the client itself sends a special packet, forcing all access points that received it to send a bacon packet in response. when the device is connected to the router, the authentication process (password) first goes through, and then the identification process, when the router and the client exchange information about their technical capabilities. then the process proceeds in the same way as over the wire, unless the device is in power-saving mode. if this mode is enabled, then it accumulates packets in the buffer waiting for polling from the router and only then sends them in a burst. the router, in turn, keeps a record of devices in power saving mode and sends this information with polling, so that all connected devices know it. so if the device is turned off, then it just disappears and that's it. no one reports anything.
and you can catch packets, for example, wireshark or another wifi sniffer. only if the network is password protected will the packets be encrypted and of little use.