Managing HP Serviceguard for Linux, Eighth Edition, March 2008

IPv6 Network Support
IPv6 Address Types
Appendix E374
IPv6 Address Types
Several IPv6 types of addressing schemes are specified in the RFC 2373
(IPv6 Addressing Architecture). IPv6 addresses are 128-bit identifiers
for interfaces and sets of interfaces. There are various address formats
for IPv6 defined by the RFC 2373. IPv6 addresses are broadly classified
as unicast, anycast, and multicast.
The following table explains the three types.
Unlike IPv4, IPv6 has no broadcast addresses; their functions are
superseded by multicast.
Textual Representation of IPv6 Addresses
There are three conventional forms for representing IPv6 addresses as
text strings:
• The first form is x:x:x:x:x:x:x:x, where the x’s are the
hexadecimal values of the eight 16-bit pieces of the 128-bit address.
Example:
2001:fecd:ba23:cd1f:dcb1:1010:9234:4088.
• Some of the IPv6 addresses may contain a long strings of zero bits. In
order to make it easy for representing such addresses textually a
special syntax is available. The use of “::” indicates that there are
Table E-1 IPv6 Address Types
Unicast An address for a single interface. A packet sent to a unicast address is
delivered to the interface identified by that address.
Anycast An address for a set of interfaces. In most cases these interfaces belong to
different nodes. A packet sent to an anycast address is delivered to one of
these interfaces identified by the address. Since the standards for using
anycast addresses are still evolving, they are not supported in Linux at
present.
Multicast An address for a set of interfaces (typically belonging to different nodes). A
packet sent to a multicast address will be delivered to all interfaces
identified by that address.