Which statement best describes the dual-stack approach in networks?

Which statement best describes the dual-stack approach in networks?

• A. IPv4 and IPv6 coexist on the same devices and networks.
• B. IPv6 is used exclusively; IPv4 is disabled.
• C. IPv4 addresses are converted to IPv6 using a fixed mapping.
• D. IPv6 uses NAT to reach IPv4 hosts.

Answer: (A)

Dual-stack means devices run both IPv4 and IPv6 protocol stacks at the same time, with each stack handling its own addressing and routing. This allows hosts to communicate using either protocol and supports a gradual transition as networks adopt IPv6. DNS can provide IPv4 or IPv6 addresses, and applications can connect via whichever path is available, often choosing IPv6 when possible but not forcing it. This coexistence on the same devices and networks is what makes dual-stack the correct description. It’s not about using IPv6 exclusively, which would drop IPv4; it isn’t about a fixed mapping from IPv4 to IPv6, which would be a translation approach; and it isn’t about NAT to reach IPv4 hosts, which is a translation method rather than true simultaneous stacks.

Dual-stack means devices run both IPv4 and IPv6 protocol stacks at the same time, with each stack handling its own addressing and routing. This allows hosts to communicate using either protocol and supports a gradual transition as networks adopt IPv6. DNS can provide IPv4 or IPv6 addresses, and applications can connect via whichever path is available, often choosing IPv6 when possible but not forcing it. This coexistence on the same devices and networks is what makes dual-stack the correct description. It’s not about using IPv6 exclusively, which would drop IPv4; it isn’t about a fixed mapping from IPv4 to IPv6, which would be a translation approach; and it isn’t about NAT to reach IPv4 hosts, which is a translation method rather than true simultaneous stacks.