Internet Protocols - CCIE Routing and Switching Exam Certification Guide - page 301

When addresses are in a mixed IPv4 and IPv6 environment, they can be represented by six
hexadecimal 16-bit pieces that are concatenated with the dotted-decimal format. This form is
represented as follows:

X:X:X:X:X:X:d.d.d.d
Each X represents the hexadecimal digits, and d.d.d.d is the dotted-decimal
representation.

An example of a mixed full address is as follows:

0000:0000:0000:0000:0000:0000:100.1.1.1

This example can be shortened to the following:

::100.1.1.1.

IPv6 Prefix Representation
IPv6 prefixes are represented similar to IPv4, as follows:

IPv6 address/prefix

The double-colon is still used only once in the representation. An example of an IPv6 prefix is
as follows:

200C:001b:1100:0:0:0:0:0/40 or 200C:1b:1100::/40.

Allocated IPv6 Addresses
The leading bits of an IPv6 address can define the address type. These leading bits are of
variable length and are called the format prefix (FP) . Table 6-19 shows some initial allocations
of some prefixes.

IPv6 Initial Prefix Allocations

Table 6-19

Binary Format Prefix Hexadecimal Allocation

0000 0000 00 Unspecified, looback, IPv4-compatible

001 2 or 3 Aggregatable global unicast address

1111 1110 10 FE8 Link-local unicast addresses

1111 1110 11 FEC Site-local unicast addresses

1111 1111 FF Multicast addresses