Unicast, Multicast and Anycast Addresses
Unicast, multicast and anycast are the ways an IP address can identify destinations: one host, a group of hosts, or the nearest of several hosts.
What is Unicast, Multicast and Anycast Addresses?
Unicast sends to a single interface. Multicast sends to all members of a group. Anycast gives the same address to many servers in different places, and routing delivers each user to the nearest one; DNS root servers and CDNs use anycast.