In IPv6, which ICMPv6 messages replace ARP for address resolution and neighbor discovery?

• A. Neighbor Solicitation and Neighbor Advertisement
• B. Router Solicitation and Router Advertisement
• C. Neighbor Advertisement and Router Advertisement
• D. Ping and Traceroute

Answer: (A)

IPv6 uses the Neighbor Discovery Protocol to handle address resolution and neighbor discovery with ICMPv6 messages. When a node needs to contact a neighbor on the same local link, it sends a Neighbor Solicitation to the target’s solicited-node multicast address to learn its link-layer (MAC) address. The neighbor responds with a Neighbor Advertisement that carries its MAC address, allowing the requester to populate its neighbor cache. This mechanism replaces the ARP process used in IPv4.

Router discovery is a separate function, done with Router Solicitation and Router Advertisement messages to identify routers and obtain network prefix information. Ping and Traceroute are general diagnostic tools and not the specific messages used for address resolution in IPv6.