PPP Authentication and Encapsulation Overview | Generated by AI
Question: Which WAN protocol is often used for authentication and encapsulation over serial links?
Answer:
The correct answer is C) PPP.
Explanation:
PPP (Point-to-Point Protocol) is a widely used WAN protocol specifically designed for establishing direct connections over serial links, such as leased lines, dial-up, or synchronous serial connections. It provides both encapsulation of network layer packets and supports authentication (commonly using PAP or CHAP).
Here’s why the other options are incorrect:
- A) RIP – Routing Information Protocol is a routing protocol, not a WAN link-layer protocol. It does not handle encapsulation or authentication over serial links.
- B) OSPF – Open Shortest Path First is also a routing protocol used for dynamic routing within networks, not for link-layer encapsulation or authentication.
- D) VLAN – Virtual LAN is a Layer 2 technology used to segment networks on Ethernet switches. It is not a WAN protocol and does not apply to serial links.
Key features of PPP that make it the right choice:
- Operates at the data link layer (Layer 2)
- Provides encapsulation for IP and other network protocols
- Supports authentication (PAP, CHAP, or MS-CHAP)
- Commonly used on serial interfaces in WAN environments (e.g., routers connected via T1/E1 lines or modem connections)
Final Answer: C) PPP
References:
- Cisco official documentation on PPP: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/bbdsl/configuration/xe-16/bba-16-ppp-over-ethernet.html
- RFC 1661 – The Point-to-Point Protocol (PPP) https://datatracker.ietf.org/doc/html/rfc1661