Data Link Layer

There used to be an audio or more of the Data Link Layer in action when using a dial-up modem, or at least a audio of a FAX connection: 

It seems they don't do this openly, anymore, but as it is hidden in the background, you don't hear the sounds  [except for FAX connections, and it appears, nobody is interested in the FAX audio anymore].

Try the videos - they give a lot of information in a simple way. I think they are quite clear but there are a lot of facts and you may need to listen a couple of times to really get to know this. For one thing, this describes why they need more than on layer.

The videos :

1. The OSI modle which is not what the Internet is using - but shows the type of things you need to do to send messages between computers.

OSI Model [closed caption]

https://www.youtube.com/watch?v=0y6FtKsg6J4

2. The promised Data Link Layer or connection link, of data communication. This allows individual addressing, and control of messages from various sources. It seems they recognized these problems [and other problems solved by the OSI Model] as they tried to send messages and found that it wasn't easy.

Data Link Layer [closed caption]

https://www.youtube.com/watch?v=c5lV995dSAA

Network Interface Card [this doesam=llthe bottom level processing - level 1 and 2.