Managing Serviceguard Eighteenth Edition, September 2010

IPv4 and IPv6 Compatibility
There are a number of techniques for using IPv4 addresses within the framework of
IPv6 addressing.
IPv4 Compatible IPv6 Addresses
The IPv6 transition mechanisms use a technique for tunneling IPv6 packets over the
existing IPv4 infrastructure. IPv6 nodes that support such mechanisms use a special
kind of IPv6 addresses that carry IPv4 addresses in their lower order 32-bits. These
addresses are called IPv4 Compatible IPv6 addresses. They are represented as follows:
Table G-3
32 bits16 bits80 bits
IPv4 address0000zeros
Example:
::192.168.0.1
IPv4 Mapped IPv6 Address
There is a special type of IPv6 address that holds an embedded IPv4 address. This
address is used to represent the addresses of IPv4-only nodes as IPv6 addresses. These
addresses are used especially by applications that support both IPv6 and IPv4. These
addresses are called as IPv4 Mapped IPv6 Addresses. The format of these address is
as follows:
Table G-4
32 bits16 bits80 bits
IPv4 addressFFFFzeros
Example:
::ffff:192.168.0.1
Aggregatable Global Unicast Addresses
The global unicast addresses are globally unique IPv6 addresses. This address format
is very well defined in the RFC 2374 (An IPv6 Aggregatable Global Unicast Address Format).
The format is:
Table G-5
64 bits16248133
Interface IDSLA IDNLA IDRESTLA IDFP
where: FP = Format prefix. Value of this is “001” for Aggregatable Global unicast
addresses.
IPv6 Address Types 477