Ipv6 Addresses; Ipv6 Address Format - Cisco 7604 Configuration Manual

Appendix E Addresses, Protocols, and Ports

IPv6 Addresses

IPv6 is the next generation of the Internet Protocol after IPv4. It provides an expanded address space, a
simplified header format, improved support for extensions and options, flow labeling capability, and
authentication and privacy capabilities. IPv6 is described in RFC 2460. The IPv6 addressing architecture
is described in RFC 3513.
This section describes the IPv6 address format and architecture and includes the following topics:
•
•
•
This section describes the IPv6 address format, the types, and prefixes. For information about
Note
configuring FWSM to use IPv6, see

IPv6 Address Format

IPv6 addresses are represented as a series of eight 16-bit hexadecimal fields separated by colons (:) in
the format: x:x:x:x:x:x:x:x. The following are two examples of IPv6 addresses:
•
•
Note The hexadecimal letters in IPv6 addresses are not case-sensitive.
It is not necessary to include the leading zeros in an individual field of the address. But each field must
contain at least one digit. So the example address 2001:0DB8:0000:0000:0008:0800:200C:417A can be
shortened to 2001:0DB8:0:0:8:800:200C:417A by removing the leading zeros from the third through
sixth fields from the left. The fields that contained all zeros (the third and fourth fields from the left)
were shortened to a single zero. The fifth field from the left had the three leading zeros removed, leaving
a single 8 in that field, and the sixth field from the left had the one leading zero removed, leaving 800 in
that field.
It is common for IPv6 addresses to contain several consecutive hexadecimal fields of zeros. You can use
two colons (::) to compress consecutive fields of zeros at the beginning, middle, or end of an IPv6
address (the colons represent the successive hexadecimal fields of zeros).
examples of address compression for different types of IPv6 address.
Table E-2
Address Type Standard Form
Unicast
Multicast
Loopback
Unspecified
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
OL-20748-01
IPv6 Address Format, page E-5
IPv6 Address Types, page E-6
IPv6 Address Prefixes, page E-10
2001:0DB8:7654:3210:FEDC:BA98:7654:3210
2001:0DB8:0000:0000:0008:0800:200C:417A
IPv6 Address Compression Examples
2001:0DB8:0:0:0:BA98:0:3210 2001:0DB8::BA98:0:3210
FF01:0:0:0:0:0:0:101
0:0:0:0:0:0:0:1
0:0:0:0:0:0:0:0
Chapter 10, "Configuring IPv6."
Compressed Form
FF01::101
::1
::
IPv6 Addresses
Table E-2 shows several
E-5