CCNA 4.2: Configure, verify, and troubleshoot PPPoE client-side interfaces using local authentication
Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol (layer 2.5?) used to encapsulate PPP frames inside of Ethernet frames.
- PPP was prevalent in the 80s and 90s. It was typically used to connect a home PC to a server at the ISP over a 56k modem phone line connection.
- Point-to-Point over Ethernet was created to solve a problem that resulted from technological advancement.
- As the internet expanded, the demand for higher bandwidth networks increased and more than one connection was needed from each home, PPPoE was the solution.
- Where PPP only connected one client to one server and did so over serial links, PPPoE can connect multiple clients to the server and does so over broadband.
- Ethernet links do not natively support PPP
- Similar to PPP, PPPoE also offers authentication, encryption and compression
- PPPoE allows the sending of PPP frames encapsulated inside Etherent frames
- Since Ethernet is a multi-access medium, PPPoE should figure out both ends MAC addresses so they can be encoded in the PPP control packet headers
- Typically, you'll want to lower the MTU to 1492 since PPP adds 2 Bytes and PPPoE addes 6 Bytes of overhead -> 1500-8 = 1492
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