How do the IPoE and PPPoE and PPPoA protocols work?

Question

Computer networks

I can not understand how the IPoE and PPPoE and PPPoA protocols physically work.
1) Do I understand correctly that IPoE is an IP packet packed into an Ethernet frame? As a rule, it is necessary for a packet to travel on the Internet (because an Ethernet frame does not have an IP, and Internet access goes by IP addresses)? Those. roughly speaking, an IP header is added to the frame in the payload so that the packet can successfully go and return?
2) PPPoE is, as far as I understand, outdated ADSL technology? Those. The PPP header is added to the Ethernet payload, it all goes up to the router, and the router already (connected to the phone jack) sends a PPP frame over the phone cable, right?
3) PPPoA - what is it? Packing PPP frames over some kind of ATM? What kind of ATM, where is it really used?

Answer 1

Once upon a time, even before the emergence of the broadband market as a whole, the PPP protocol was widely used. It mainly worked on WAN interfaces (not yet Ethernet, often serial type RS232). This protocol had advanced functionality that is not available in ethernet, first of all, operators are interested in authentication and connection control, and for xDSL connections, advanced control of broken packets (errors) is also important. PPP is a link layer protocol, in fact, like ethernet, each frame has its own header.
So, to transfer PPP over ethernet, PPPoE is used. And this is necessary in order to use the advanced functionality of PPP. The packet structure looks like this - (ethernet header (PPP header (IP header (data)))).
PPPoA is the same as PPPoE, only through the ATM network. ATM is the same technology for accessing communication channels, only it is not at all common in the Russian Federation and the CIS. But it is still used in the West. I saw live ATM in the Russian Federation about 10 years ago in one large corporate network. But here, too, ethernet has long since survived it.
IPoE is already more interesting. In fact, this is a normal transmission of IP packets, as written in TCP / IP books. Typically, this term is used as a replacement for PPPoE. But Ethernet and IP lack advanced authentication and connection control functionality. And here various technologies like ISG, dhcp snooping are already replacing. In general, IPoE is spoken mainly in operator networks and, in addition to passing traffic, implies some implemented access control scheme to the service.

Answer 2

> an IP header is added to the frame in the payload so that the packet can successfully go and return
no, an ethernet header is added to the IP packet in the payload so that the packet can move on the ethernet network.

Answer 3

Schoolboy detected?
PPPoA
PPPoE
IPoE

Answer 4

Everything was almost correctly understood; I will clarify that IPoE is ordinary IP packets, so named for the (apparently) marketing needs of Internet operators, and PPPoE does not necessarily go over a telephone cable - it's just an encapsulation of PPP in Ethernet.