TP-Link TL-SG2424 User Manual page 29

Anycast address: An identifier for a set of interfaces (typically belonging to different nodes).

A packet sent to an anycast address is delivered to one of the interfaces identified by that
address (the nearest one, according to the routing protocols' measure of distance).
The type of an IPv6 address is designated by the first several bits called format prefix. The
following table lists the mappings between address types and format prefixes.
Unassigned address
Loopback address
Link-local address
Unicast
address
Site-local address
Global unicast address
(currently assigned)
Reserved type
(to be assigned in future)
Multicast address
Anycast address
Table 4-1 Mappings between address types and format prefixes
3. IPv6 Unicast Address：
IPv6 unicast address is an identifier for a single interface. It consists of a subnet prefix and an
interface ID.
Subnet Prefix: This section is allocated by the IANA (The Internet Assigned Numbers

Authority), the ISP (Internet Service Provider) or the organizations.
Interface ID: An interface ID is used to identify interfaces on a link. The interface ID must be

unique to the link.
There are several ways to form interface IDs. The IPv6 addresses with format prefixes 001
through 111, except for multicast addresses (1111 1111), are all required to have 64-bit
interface IDs in EUI-64 format.
For all IEEE 802 interface types (for example, Ethernet and FDDI interfaces), Interface IDs in
the modified EUI-64 format are constructed in the following way:
The first three octets (24 bits) are taken from the Organizationally Unique Identifier (OUI) of the
48-bit link-layer address (the MAC address) of the interface, the fourth and fifth octets (16 bits)
are a fixed hexadecimal value of FFFE, and the last three octets (24 bits) are taken from the
last three octets of the MAC address. The construction of the interface ID is completed by
Type Format Prefix (binary)
00...0 (128 bits)
00...1 (128 bits)
1111111010
1111111011
001
Other formats
11111111
Anycast addresses are taken from unicast
address space and are not syntactically
distinguishable from unicast addresses.
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IPv6 Prefix ID
::/128
::1/128
FE80::/10
FEC0::/10
2xxx::/4 or 3xxx::/4
FF00::/8