CCNA Routing and Switching (legacy) — Question 25

Which PPP subprotocol negotiates authentication options?

Answer options

• A. NCP
• B. LCP
• C. ISDN
• D. DLCI
• E. SLIP B

Correct answer:

Explanation

The correct answer is LCP (Link Control Protocol) because it is the protocol in PPP that negotiates authentication options and establishes the link parameters. NCP is used for network layer protocol configuration, while ISDN and DLCI are unrelated to PPP subprotocols, and SLIP is a different protocol altogether.