Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007, Installation Manual

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Site Topology
The second part contains routing information about the subnetwork to which to
deliver the packet.
Interface ID
The third part identifies the interface to which to deliver the packet. This also allows
for the MAC to form part of the address. Given that the MAC is a globally unique,
fixed identifier coded into the device by the hardware maker, the configuration
procedure is substantially simplified. In fact, the first 64 address bits are consoli-
dated to form the
EUI-64
token, with the last 48 bits taken from the MAC, and
the remaining 24 bits containing special information about the token type. This also
makes it possible to assign an
EUI-64
token to interfaces that do not have a MAC,
such as those based on PPP or ISDN.
On top of this basic structure, IPv6 distinguishes between five different types of unicast
addresses:
::
(unspecified)
This address is used by the host as its source address when the interface is initialized
for the first time—when the address cannot yet be determined by other means.
::1
(loopback)
The address of the loopback device.
IPv4 Compatible Addresses
The IPv6 address is formed by the IPv4 address and a prefix consisting of 96 zero
bits. This type of compatibility address is used for tunneling (see
Section 30.2.3,
“Coexistence of IPv4 and IPv6” (page 556)) to allow IPv4 and IPv6 hosts to com-
municate with others operating in a pure IPv4 environment.
IPv4 Addresses Mapped to IPv6
This type of address specifies a pure IPv4 address in IPv6 notation.
Local Addresses
There are two address types for local use:
link-local
This type of address can only be used in the local subnetwork. Packets with a
source or target address of this type should not be routed to the Internet or
other subnetworks. These addresses contain a special prefix (
fe80::/10
)
and the interface ID of the network card, with the middle part consisting of
Basic Networking 555