Overview of PPP

The Point-to-Point Protocol (PPP) is a data link-layer protocol used to transmit and encapsulate network layer packets on point-to-point (P2P) links.

Definition

A P2P connection is a simple WAN connection. Link layer protocols of a P2P connection include Point-to-Point Protocol (PPP). PPP supports both synchronous and asynchronous transmission.

PPP defines a set of protocols:

Link Control Protocol (LCP): used to establish, monitor, and terminate data links.
Network Control Protocol (NCP): used to establish and configure different network layer protocols and negotiate the format and type of packets transmitted over data links.
Authentication protocols: include Password Authentication Protocol (PAP) and Challenge-Handshake Authentication Protocol (CHAP).

Objective

Located at the data link layer of the Open Systems Interconnection (OSI) model, PPP supports both synchronous or asynchronous full-duplex links to transmit data. PPP is widely used because it has the following advantages:

Provides user authentication.
Supports synchronous and asynchronous communications.
Is easily expanded.