IPv6 Address Types

IPv6 Address Types
IPv6 defines three types of addresses: unicast, anycast, and multicast. A unicast address is used to
represent a single interface on a device. A packet that is sent to a unicast address is delivered to the
interface identified by that address.
An anycast address is used to identify multiple different interfaces. A packet that is sent to an
anycast address will be delivered to the closest interface that has that anycast address assigned.
The routing protocol will determine which device will get the packet, based on shortest distance.
A multicast address is used to address a set of interfaces (within a certain scope) that will receive
the same packet. This is not unlike the way multicast works in the IPv4 world, except that there are
a lot more multicast addresses available. Let’s discuss each of these address types in greater detail.
IPv6 Unicast Address
There are different types of unicast addresses:
 Global unicast address
 Site-local unicast address
 Link-local unicast address
 IPv4-mapped IPv6 address
 IPv4-compatible IPv6 address
 Unspecified address
The other type of unicast address, 0:0:0:0:0:0:0:1, or ::1, is the loopback address and performs
the same function as 127.0.0.1 does in IPv4. It is used to identify a transmission sent by
a node back to itself, usually for testing purposes, and should never leave the sending node. This
cannot be assigned to a physical interface, and IPv6 routers do not forward traffic either sourced
from or destined to this address.