47
Type
Format prefix
(binary)
IPv6 prefix ID
Remarks
Unicast
address
Unspecified
address
00...0 (128 bits)
::/128
It cannot be assigned to any node.
Before acquiring a valid IPv6
address, a node fills this address
in the source address field of IPv6
packets. The unspecified address
cannot be used as a destination
IPv6 address.
Loopback
address
00...1 (128 bits)
::1/128
It has the same function as the
loopback address in IPv4. It
cannot be assigned to any
physical interface. A node uses
this address to send an IPv6
packet to itself.
Link-local
address
1111111010 FE80::/10
Used for communication among
link-local nodes for neighbor
discovery and stateless
autoconfiguration. Packets with
link-local source or destination
addresses are not forwarded to
other links.
Global unicast
address
Other forms
N/A
Equivalent to public IPv4
addresses, global unicast
addresses are provided for
Internet service providers. This
type of address allows for prefix
aggregation to restrict the number
of global routing entries.
Multicast address
11111111 FF00::/8 N/A
Anycast address
Anycast addresses use the unicast
address space and have the identical
structure of unicast addresses.
N/A
EUI-64 address-based interface identifiers
An interface identifier is 64-bit long and uniquely identifies an interface on a link. Interfaces generate
EUI-64 address-based interface identifiers differently.
On an IEEE 802 interface (such as a VLAN interface), the interface identifier is derived from the
link-layer address (typically a MAC address) of the interface. The MAC address is 48-bit long.
To obtain an EUI-64 address-based interface identifier, follow these steps:
1.
Insert the 16-bit binary number 1111111111111110 (hexadecimal value of FFFE) behind the
24th high-order bit of the MAC address.
2.
Invert the universal/local (U/L) bit (the seventh high-order bit). This operation makes the
interface identifier have the same local or global significance as the MAC address.
IPv6 global unicast address configuration methods
Use one of the following methods to configure an IPv6 global unicast address for an interface:
•
EUI-64
IPv6
address
—The IPv6 address prefix of the interface is manually configured, and the
interface identifier is generated automatically by the interface.
•
Manual
configuration
—The IPv6 global unicast address is manually configured.
