Managing HP Serviceguard for Linux, Tenth Edition, September 2012

of the 32-bit lower order bits. Typically IPv4 Mapped IPv6 addresses and IPv4
Compatible IPv6 addresses will be represented in this notation. These addresses are
discussed in later sections.
Examples:
0:0:0:0:0:0:10.1.2.3
and
::10.11.3.123
IPv6 Address Prefix
IPv6 Address Prefix is similar to CIDR in IPv4 and is written in CIDR notation. An IPv6
address prefix is represented by the notation:
IPv6-address/prefix-length where ipv6-address is an IPv6 address in any
notation listed above and prefix-length is a decimal value representing how many
of the leftmost contiguous bits of the address comprise the prefix. Example:
fec0:0:0:1::1234/64
The first 64-bits of the address fec0:0:0:1 forms the address prefix. An address prefix
is used in IPv6 addresses to denote how many bits in the IPv6 address represent the
subnet.
Unicast Addresses
IPv6 unicast addresses are classified into different types. They are: global aggregatable
unicast address, site-local address and link-local address. Typically a unicast address is
logically divided as follows:
Table 12
128-n bitsn bits
Interface IDSubnet prefix
Interface identifiers in a IPv6 unicast address are used to identify the interfaces on a link.
Interface identifiers are required to be unique on that link. The link is generally identified
by the subnet prefix.
A unicast address is called an unspecified address if all the bits in the address are zero.
Textually it is represented as “::”.
The unicast address ::1 or 0:0:0:0:0:0:0:1 is called the loopback address. It is
used by a node to send packets to itself.
IPv4 and IPv6 Compatibility
There are a number of techniques for using IPv4 addresses within the framework of IPv6
addressing.
IPv6 Address Types 329