link layer

Who Are You 🎵? Imagine that Host $A$ and Host $B$ are in the same room and want to communicate with each other, and lets assume for now that communication is totally possible across some medium (like Wi-Fi) without any problems.

How Do We Actually Send Messages to People? In our previous page, we said in a hand-wavy way that we “send” messages to people via their MAC address. But how do we actually send these messages to people?

What if Nobody is in Control? In our previous example of switched networks, there were hidden switch devices that were responsible for the forwarding of communication between various devices, and in this way the network works wonderfulling like magic.

Error Detection and Error Correction With all the discussion on the previous page, there is a follow up question of how a receiver of a message might realize that something has gone wrong, and thus act accordingly.