Difficulty: Easy
Correct Answer: VPN
Explanation:
Introduction / Context:This item distinguishes the general concept of Virtual Private Networks (VPNs) from specific technologies. A VPN is a method of using shared networks to provide private connectivity with encapsulation and security.
Given Data / Assumptions:
Concept / Approach:VPN is a broad term that encompasses technologies allowing creation of logical private links over public infrastructure. Features include tunneling (encapsulation), authentication, integrity, and often encryption. Implementations may use IPSec, SSL/TLS, GRE combined with IPSec, or MPLS-based L3VPN/L2VPNs, among others.
Step-by-Step Solution:
Identify the generic description: 'private networks across the Internet' and 'tunneling' → fits VPN.Exclude link/physical technologies (HDLC, Cable, xDSL) that do not inherently provide privacy over the Internet.Exclude IPSec since it is a specific suite; the question asks for the overall concept.Verification / Alternative check:Common deployments label SSL remote-access and IPSec site-to-site solutions collectively as VPNs; GRE tunnels can carry non-IP protocols over IP and are often protected by IPSec.
Why Other Options Are Wrong:IPSec: A specific standard protocol suite, not the umbrella concept. HDLC/Cable/xDSL: Access technologies, not privacy/tunneling solutions across the Internet.
Common Pitfalls:Confusing IPSec (implementation) with VPN (service/concept). The question wording favors the concept.
Final Answer:VPN
show frame-relay ?, which of the following subcommands are available: dlci, neighbors, lmi, pvc, map?
Discussion & Comments