Which protocol is the IPv6 version of ARP and what messages does it use?

• A. NDP using Neighbor Solicitation and Neighbor Advertisement
• B. ICMPv6 messages for discovery
• C. DHCPv6 messages
• D. ARP over IPv6

Answer: (A)

IPv6 handles address-to-MAC resolution with a different mechanism than ARP. The on-link neighbor discovery protocol is built on ICMPv6, and its primary messages for resolving a neighbor’s link-layer address are Neighbor Solicitation and Neighbor Advertisement. When a node needs to map an IPv6 address to a MAC address, it sends a Neighbor Solicitation to the target’s solicited-node multicast address, and the target replies with a Neighbor Advertisement that includes its link-layer address. This replaces ARP’s request/reply pattern from IPv4 while also enabling additional link-layer and neighbor-related features, such as duplicate address detection.

Other options don’t fit because ICMPv6 has many message types, but the specific pair used for address resolution is Neighbor Solicitation and Neighbor Advertisement. DHCPv6 handles configuring addresses and other options, not replacing ARP, and there is no ARP over IPv6.