What is one function of Neighbor Solicitation (NS) messages?

Neighbor Solicitation (NS) messages are an integral part of the Neighbor Discovery Protocol, which is used in IPv6 networks. One of the key functions of Neighbor Solicitation messages is to request the link-layer addresses of other devices on the same local network segment. When a device needs to communicate with another device for which it knows the IPv6 address but not the corresponding MAC address, it sends out an NS message to solicit this information. This helps facilitate direct communication over Ethernet or another link-layer technology.

In scenarios where devices operate within the same local area network, having the correct link-layer address is crucial for encapsulating the IPv6 packets for transmission. The NS messages are received by the target device, which then responds with a Neighbor Advertisement (NA) message, providing its link-layer address back to the requester. This process is vital for functions such as ARP in IPv4 networks but is handled differently yet effectively in IPv6 through the Neighbor Discovery Protocol.