In IPv6, what is the purpose of link-local addresses?

• A. Used for neighbor discovery and essential control plane communications on the local link; scope is link-local (fe80::/64).
• B. Used for global Internet routing.
• C. Used for remote site-to-site VPN encryption.
• D. Used to identify hosts across multiple links.

Answer: (A)

Link-local addresses are meant to operate only on the local network segment and are automatically created on every IPv6-enabled interface. They provide a reliable way for devices on the same link to find and talk to each other without needing global reachability. The key use is neighbor discovery and related control traffic: devices use these addresses to resolve neighbors, detect duplicates, and exchange essential ICMPv6 messages such as router advertisements and neighbor solicitations that keep the local link functional. Because their scope is link-local, packets using these addresses are not routed beyond the local network, which is what makes them ideal for the immediate control plane communications needed on that link. Global Internet routing relies on globally routable addresses, not link-local ones, and multiple links require addresses with broader scope to reach across networks. So the purpose of link-local addresses is to support neighbor discovery and essential control communications on the local link, with fe80::/64 as their typical range.