🔌Point-to-Point Protocol

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Also known as: PPP

A data link layer protocol establishing direct connections and transporting multiprotocol datagrams over point-to-point links.

DESCRIPTION

Point-to-Point Protocol (PPP) is an IETF standard for encapsulating network-layer datagrams over serial or point-to-point links. It provides Link Control Protocol (LCP) for link establishment and negotiation, and Network Control Protocols (NCPs) for configuring different network layer protocols. PPP supports authentication via PAP or CHAP, error detection, and optional compression. It underpinned dial-up Internet access and remains foundational in tunneling variants like PPPoE and L2TP.

ALTERNATIVE DEFINITIONS

IETF RFC 1661

The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links.

Emphasizes PPP’s multi-protocol transportation and point-to-point nature.

Source

Wikipedia

Point-to-Point Protocol (PPP) is a data link layer (layer 2) communications protocol used to establish a direct connection between two nodes.

Highlights OSI layering and the direct-connection use case.

Source

RELATED TERMS

PPPoE L2TP HDLC Link Control Protocol Network Control Protocol Challenge-Handshake Authentication Protocol Password Authentication Protocol Data Link Layer TCP

COMPETING TERMS

SLIP

RELATIONS

• Broader: Protocol

KNOWLEDGE AREAS

Infrastructure Data Integration & Interoperability

TARGET AUDIENCE

Cloud Architect Security Architect DevOps Engineer IT Manager Software Architect

EXTERNAL SOURCES

• Wikipedia - Point-to-Point Protocol
• IETF - Canonical PPP specification
• IETF Datatracker - RFC metadata and history
• Cisco - PPP configuration guide

TOP QUESTIONS

What is Point-to-Point Protocol (PPP)?

PPP is a layer 2 protocol that transports multiprotocol datagrams over point-to-point links, with link control and authentication support.

Category: Definition

Why did PPP matter historically?

PPP enabled dial-up Internet connectivity, providing reliable link negotiation and authentication over serial lines.

Category: Relevancy

How does PPP authenticate connections?

PPP supports PAP and CHAP for authentication, with CHAP offering stronger protection via challenge-response.

Category: Requirements

What are PPP’s key components?

LCP negotiates link parameters; NCP configures network-layer protocols like IP; optional compression and error detection are included.

Category: Concepts

What are common PPP alternatives?

SLIP is a predecessor but lacks features; PPPoE and L2TP use PPP framing within modern network contexts.

Category: Alternatives

Is PPP still relevant today?

While dial-up has faded, PPP’s derivatives and concepts appear in tunneling and broadband protocols.

Category: Opinion

What mistakes occur when deploying PPP?

Misconfigured authentication, mismatched MTU/MRU, and ignoring LCP options can cause instability.

Category: Mistakes

How does PPP compare to Ethernet?

PPP is point-to-point at layer 2; Ethernet is multi-access with different framing and discovery mechanisms.

Category: Comparison

Where can I learn PPP configuration?

IETF RFCs and vendor guides like Cisco provide detailed configuration and troubleshooting instructions.

Category: Learning