Neighbor Discovery Protocol

Abbr	Names	ICMPv6 Tpyes	Description	Provide Functions
RS	Router Solicitation	Type 133	Locate routers on a local link; Sent to multicast address ff02::2
RA	Router Advertisement	Type 134	Response to RS or sent periodically to announce presences and other info; Sent to multicast address ff02::1
NS	Neighbor Solicitation	Type 135	Discover a neighbor's MAC address; Verify if a neighbor is still reachable	'ARP', DAD
NA	Neighbor Advertisement	Type 136	Response to NS, or unsolicited to provide info	'ARP', DAD
	Redirect	Type 137	A better next-hop route for a destination

DAD (Duplicate Address Detection)

• A host send an NS to its own IPv6 address.
• If no response get, it knows the address is unique.
• If get a reply, it means another host on the network is already using the address.