Managing HP Serviceguard for Linux, Tenth Edition, September 2012

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 13
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 14
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 15
64 bits16248133
Interface IDSLA IDNLA IDRESTLA IDFP
where
FP = Format prefix. Value of this is “001” for Aggregatable Global unicast addresses.
TLA ID = Top-level Aggregation Identifier.
RES = Reserved for future use.
NLA ID = Next-Level Aggregation Identifier.
SLA ID = Site-Level Aggregation Identifier.
330 IPv6 Network Support