PPP and PPPoE Networking for DSL

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Point-to-Point Protocol (PPP) and Point-to-Point Protocol over Ethernet (PPPoE) are both network protocols that allow communications between two network points. They are similar in design with the obvious difference that PPPoE is encapsulated in Ethernet frames.


From a home networking standpoint, PPP's heyday was during the days of dial-up networking. PPPoE is its high-speed transfer successor.

  • PPP enables reliable TCP/IP networking over serial line connections. PPP emerged in the 1990s as a replacement for Serial Line Internet Protocol (SLIP) and was most commonly used for dial-up networking between modems
  • PPPoE is a network protocol derived from PPP designed for use with broadband modems and DSL internet service. PPPoE allows internet service providers to manage access to accounts via usernames and passwords. DSL service providers began using PPPoE years ago because it was a convenient technical solution for converting subscribers from the dial-up internet. Most internet service providers support the PPPoE protocol.

PPP operates at Layer 2, the Data Link, of the OSI model. It is specified in RFCs 1661 and 1662. The PPPoE protocol specification, which is sometimes referred to as a Layer 2.5 protocol, is specified in RFC 2516.

Configuring PPPoE on a Home Router

Mainstream home broadband routers provide options on their administrator consoles for PPPoE support. An administrator must first select PPPoE from a list of broadband internet service options and then enter a username and password for connecting to the broadband service. The username and password, along with other recommended settings, are supplied by the internet provider.

Other Technical Details

While convenient for service providers, a few customers of PPPoE-based internet service experienced problems with their connection due to incompatibility between PPPoE technology and their personal network firewalls. Contact your service provider to get any assistance needed with your firewall settings.