Operation Manual

21
Type Format Prefix (binary) IPv6 Prefix ID
Unicast
address
Unassigned address 00…0 (128 bits) ::/128
Loopback address 00…1 (128 bits) ::1/128
Link-local address 1111111010 FE80::/10
Site-local address 1111111011 FEC0::/10
Global unicast address
(currently assigned)
001 2xxx::/4 or 3xxx::/4
Reserved type
(to be assigned in future)
Other formats
Multicast address 11111111 FF00::/8
Anycast address
Anycast addresses are taken from unicast
address space and are not syntactically
distinguishable from unicast addresses.
Table 4-1 Mappings between address types and format prefixes
IPv6 unicast address can be classified into several types, including global unicast address,
link-local address, and site-local address. The two most common types are introduced
below:
 Global unicast address
A Global unicast address is an IPv6 unicast address that is globally unique and is
routable on the global Internet.
Global unicast addresses are defined by a global routing prefix, a subnet ID, and an
interface ID. Except for addresses that start with binary 000, all global unicast
addresses have a 64-bit interface ID. The IPv6 global unicast address allocation uses
the range of addresses that start with binary value 001 (2000::/3). The figure below
shows the structure of a global unicast address.
Figure 4-8 Global Unicast Address Format