What type of protocol is PPP primarily used for?

PPP, or Point-to-Point Protocol, is primarily used as a data link protocol for establishing a direct connection between two networking nodes. This capability makes it essential for point-to-point communication over various types of physical media, such as serial cable, phone lines, or fiber optics. One of the key features of PPP is its ability to encapsulate multiple network layer protocols, providing a standard method to transmit data packets over the direct connection.

PPP supports various functionalities, including authentication (using protocols like PAP or CHAP), and it can detect errors in transmission, making it a reliable choice for establishing direct connections. Its design allows it to negotiate link parameters dynamically, which is particularly important in dial-up access scenarios.

In contrast, while tunneling protocols for VPNs facilitate secure communication over potentially untrusted networks, and communication protocols for internet exposure relate to the broader internet framework, these aspects do not align directly with PPP's primary function as a direct connection protocol. Network virtualization technologies often deal with the abstraction of physical resources, which also does not reflect the core purpose of PPP as a basic data link protocol. Thus, the identification of PPP as primarily a data link protocol accurately captures its fundamental role in networking.