PPP vs PPoE

[oogando]

Hello All,

I am studying for my CCNA and I am having some problems understanding PPP vs PPPoE.

The way I understand it is that PPP is serial communication Layer two protocol. It helps establish and authenticate a connection between two nodes.. PPPoE encapsulates PPP into a frame? but isn't PPP a frame since it s a layer 2 protocol?

Why is PPPoE needed at all? I have not found a good explanation.

Thank you!

[Joseph W. Doherty]

I believe you often find PPPoE when working with ADSL, which is often based on ATM. I think (?) the PPPoE is really mostly used to validate you host is allowed to use the link. (I do know, it takes a few bytes from the IP MTU.)