IP anycast point-to-(any) point communication

The Internet supports three communication paradigms. The first, unicast, is the point-to-point flow of packets between a single source (client) and destination (server) host. Web browsing and file Me transfer are unicast applications. The next, multicast, is the point-to-multipoint flow of packets between a single source host and one or more destination hosts. Broadcast-style videoconferencing, for example, employs IP multicast. Anycast is the point-to-point flow of packets between a single client and the "nearest" destination server identified by an anycast address. The idea behind anycast is that a client wants to send packets to any one of several possible servers offering a particular service or application but does not really care which one. Any number of servers can be assigned a single anycast address within an anycast group. A client sends packets to an anycast server by placing the anycast address in the packet header. Routers then attempt to deliver the packet to a server with the matching anycast address