RFC 4681

RFC 4681 - Neighbor Discovery for IP version 6 - specifies the Neighbor Discovery protocol for IPv6.

IPv6 nodes on the same link use Neighbor Discovery to discover each other's presence, to determine each other's link-layer addresses, to find routers, and to maintain reachability information about the paths to active neighbors.

More information

https://tools.ietf.org/html/rfc4681