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.

Study Notes:

  • 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



PacketTracer Lab: CCNA-4.2-Configure-verify-and-troubleshoot-PPPoE-client-side-interfaces-using-local-authentication.pkt

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