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The TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Network Interface Layer (OSI Data Link Layer) Protocols            9  TCP/IP Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP)                 9  Point-to-Point Protocol (PPP)

PPP Standards 1 PPP Link Control Protocol (LCP)

The PPP protocol suite consists of several dozen protocols that cover various aspects of its operation. Of these, a few protocols can be considered the most important or “core” of the suite. It's not that the others are not important, mind you. But this small group is responsible for the basic operation of PPP. In particular, they work together to implement the relatively complex link negotiation process, which is a big part of what PPP is all about.

In this section I describe the protocols that are responsible for PPP link setup and basic operation. I begin with a description of the key Link Control Protocol (LCP). I then describe the different Network Control Protocols (NCPs) used to configure PPP for different layer three protocols. Finally, I discuss the two PPP authentication protocols, PAP and CHAP, used to provide authentication during link setup.

PPP Standards 1 PPP Link Control Protocol (LCP)