Related Documentation
IPv6 Neighbor Discovery Protocol Overview
Neighbor Discovery is a protocol in the IPv6 protocol suite that allows nodes on the same link to advertise their existence to their neighbors and to learn about the existence of their neighbors. Neighbor Discovery is built on top of Internet Control Message Protocol version 6 (ICMPv6). It replaces the following IPv4 protocols: Router Discovery (RDISC), Address Resolution Protocol (ARP), and ICMPv4 redirect.
Neighbor Discovery uses router advertisement messages to detect neighbors, advertise IPv6 prefixes, assist in address provisioning, and share link parameters such as MTU, hop limit, advertisement intervals, and lifetime.
Neighbor Discovery Messages
Neighbor Discovery uses the following message types:
- Router advertisement (RA)—Messages sent to announce the presence of the router, advertise prefixes, assist in address configuration, and share other link information such as MTU size and hop limit. The IPv6 nodes on the link can use this information to configure themselves with an IPv6 address and routing information such as the default gateway.
- Router solicitation (RS)—Messages sent by IPv6 nodes when they come online to solicit immediate router advertisements from the router.
- Neighbor solicitation (NS)—Messages used for duplicate
address detection and to test reachability of neighbors.
A host can verify that its address is unique by sending a neighbor solicitation message destined to the new address. If the host receives a neighbor advertisement in reply, the address is a duplicate.
- Neighbor advertisement (NA)—Messages used for duplicate address detection and to test reachability of neighbors. Neighbor advertisements are sent in response to neighbor solicitation messages.
You can specify the information that is sent in router advertisements.
