PPP

/ˌpiː-piː-ˈpiː/

n. “The protocol that wraps network packets for point-to-point links.”

PPP, short for Point-to-Point Protocol, is a data link layer protocol used to establish direct connections between two networked devices over serial links, telephone lines, or other point-to-point connections. It encapsulates network layer packets (like IP) into frames for transmission and provides features like authentication, compression, and error detection.

Key characteristics of PPP include:

• Encapsulation: Wraps network layer packets into PPP frames for transmission over point-to-point links.
• Error Detection: Uses CRC checksums to verify data integrity.
• Authentication: Supports protocols such as PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication Protocol).
• Multiprotocol Support: Can carry multiple network layer protocols, including IPv4, IPv6, and others.
• Flexible and Lightweight: Minimal overhead, suitable for slow serial connections and dial-up networks.

A conceptual example of PPP usage:

Computer A <--- PPP Frame (encapsulated IP packet) ---> Computer B
Frame includes:
- Start/End Flags
- Address & Control fields
- Protocol type (e.g., IP)
- Payload (actual data)
- CRC for error checking

Conceptually, PPP is like putting a letter (IP packet) into an envelope (PPP frame) with a return address and a seal (CRC) before sending it directly to another person over a private line.

In essence, PPP enables reliable, authenticated, and multiprotocol communication over point-to-point links, making it foundational for dial-up networking, serial connections, and some VPNs.