What feature allows a device to support both IPv4 and IPv6 protocols?

• A. Dual IP stack
• B. Multihoming
• C. Protocol bridging
• D. Service bilingualism

Answer: (A)

The correct answer is a dual IP stack. This feature enables a network device to utilize both Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) simultaneously. By having a dual IP stack, devices can communicate on both IPv4 and IPv6 networks, allowing for a smooth transition during the phase-out of IPv4 addresses as the internet moves towards IPv6 due to its larger address space and improved features.

Dual IP stacking works by assigning separate IP addresses from each of the protocols to the same network interface, enabling the device to send and receive packets using either protocol as needed. This is particularly important as many devices and networks continue to operate on IPv4 while newer infrastructures adopt IPv6.

Other options do not specifically refer to the ability to run both protocols side by side in this manner. Multihoming involves connecting a device to multiple networks, enhancing reliability and redundancy but not necessarily enabling both IP protocols. Protocol bridging relates to connecting different networks at the data link layer and does not inherently provide dual support for IP protocols. Service bilingualism is not a standard term in networking and does not apply to IP protocol usage directly.