Anycast address is a special type of address that identifies multiple interfaces. Any packets addressed to an anycast address
are delivered to a single [any] interface - the nearest interface (that is configured with the anycast address) to the sending
host in terms of routing distance. While unicast address
is used for one-to-one communication,
and multicast address
is used for one-to-many communication, an anycast address is used for
one-to-one-of-many communication, which deliver data to one of the many available interfaces.
In order to facilitate delivery to the nearest anycast group member, the routing infrastructure must be aware of the interfaces
that are assigned anycast addresses and their distances in terms of routing metrics. Anycast addresses are assigned from the
unicast address space. The scope of an anycast address is the scope of the type of unicast address from which the anycast
address is assigned.