Stands for "Point-to-Point Protocol." PPP is a protocol that enables communication and data transfer between two points or "nodes." For many years, PPP was the standard way to establish a dial-up connection to an ISPs. As dial-up modems were superseded by broadband devices, PPP connections became increasing. However, PPP lives on in "PPP over Ethernet" (PPPoE), which is a common way to connect to the Internet using a DSL modem.
PPP is a data link protocol, which is the second layer of the seven-layer OSI model. It comes just after the physical layer and encapsulates the five layers underneath it. This means PPP can be used by multiple applications and may transfer data over multiple protocols, such as TCP and UDP. It commonly uses the Internet protocol (IP) to transfer data over the Internet.
Because PPP encapsulates other protocols, it can be used for data tunneling, or securely transferring data within the PPP protocol. The Point-to-Point Tunneling Protocol (PPTP was designed for this purpose and is often used to create virtual private networks VPNs. However, PPP was not originally designed as a secure protocol and has some known security vulnerabilities. Therefore modern VPNs often use other protocols.
PPPoE, or PPP over Ethernet, is a standard way to connect to an ISP using a DSL modem. It allows you to connect your modem to a computer or router using a high-speed Ethernet port. The modem then establishes a point-to-point connection with the ISP. PPP supports authentication, so you may be asked to enter a username and password in the PPPoE settings. This information provides a simple way for your DSL Internet provider to confirm you are a valid subscriber.