Novell LINUX ENTERPRISE SERVER 11 - ADMINISTRATION Administration Manual page 223

An IPv6 address is made up of eight four-digit fields, each representing 16 bits, written
in hexadecimal notation. They are also separated by colons (:). Any leading zero bytes
within a given field may be dropped, but zeros within the field or at its end may not.
Another convention is that more than four consecutive zero bytes may be collapsed
into a double colon. However, only one such :: is allowed per address. This kind of
shorthand notation is shown in
all three lines represent the same address.
Example 17.3 Sample IPv6 Address
fe80 : 0000 : 0000 : 0000 : 0000 : 10 : 1000 : 1a4
fe80 : 0 : 0 :
fe80 :
Each part of an IPv6 address has a defined function. The first bytes form the prefix and
specify the type of address. The center part is the network portion of the address, but
it may be unused. The end of the address forms the host part. With IPv6, the netmask
is defined by indicating the length of the prefix after a slash at the end of the address.
An address, as shown in
(page 209), contains the information that the first 64 bits form the network part of the
address and the last 64 form its host part. In other words, the 64 means that the netmask
is filled with 64 1-bit values from the left. Just like with IPv4, the IP address is combined
with AND with the values from the netmask to determine whether the host is located
in the same subnetwork or in another one.
Example 17.4 IPv6 Address Specifying the Prefix Length
fe80::10:1000:1a4/64
IPv6 knows about several predefined types of prefixes. Some of these are shown in
Table 17.4, "Various IPv6 Prefixes"
Table 17.4 Various IPv6 Prefixes
Prefix (hex)
00
Example 17.3, "Sample IPv6 Address"
0 : 0 : 10 : 1000 : 1a4
: 10 : 1000 : 1a4
Example 17.4, "IPv6 Address Specifying the Prefix Length"
(page 209).
Definition
IPv4 addresses and IPv4 over IPv6 compatibility addresses. These
are used to maintain compatibility with IPv4. Their use still re-
quires a router able to translate IPv6 packets into IPv4 packets.
Several special addresses, such as the one for the loopback device,
have this prefix as well.
(page 209), where
Basic Networking 209