IPv6 is the second version of the Internet Protocol to be widely deployed, and is expected (as of 2001) to form the basis for future expansion of the internet. In 2003, Nihon Keizai Shimbun (as cited in CNET Asia Staff, 2003) reported that Japan, China, and South Korea claimed to have made themselves determined to become the leading nations in internet technology, which would partially take the form of jointly developing IPv6, and completely adopting IPv6 starting in 2005.
The compelling reason behind the formation of IPv6 was lack of address space, especially in the heavily populated countries of Asia such as India and China.
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2 Notation for IPv6 addresses 3 IPv6 deployment 4 Related IETF working groups 5 External links 6 References |
The most dramatic change from IPv4 to IPv6 is the length of network addresses. IPv6 addresses, as defined by RFC 2373 and RFC 2374, are 128 bits long; this corresponds to 32 hexadecimal digits, which are normally used when writing IPv6 addresses, as described in the following section.
The number of possible addresses in IPv6 is 2128 ≈ 3.4 x 1038. The number of IPv6 addresses can also be thought of as 1632 as each of the 32 hexadecimal digits can take 16 values (see combinatorics).
In some situations, IPv6 addresses are composed of two logical parts: a 64-bit network prefix, and a 64-bit host-addressing part, which is often automatically generated from the interface MAC address.
IPv6 addresses are 128 bits long but are normally written as eight groups of 4 hexadecimal digits each. For example,
If a 4 digit group is 0000, it may be omitted. For example,
Also leading zeros in all groups can be omitted, thus
IPv4 addresses are easily convertible to IPv6 format. For instance, if the IPv4 address was 135.75.43.52, it could be converted to 0000:0000:0000:0000:0000:0000:874B:2B34 or ::874B:2B34. Then again, one could use the hybrid notation (IPv4 mapped addresses), in which case the address would be ::135.75.43.52 .
To do:
IPv6 addressing
Notation for IPv6 addresses
3ffe:6a88:85a3:08d3:1319:8a2e:0370:7344
is a valid IPv6 address.3ffe:6a88:85a3:0000:1319:8a2e:0370:7344
is the same IPv6 address as
3ffe:6a88:85a3::1319:8a2e:0370:7344
Following this rule, if more than two consecutive colons result from this omission, they may be reduced to two colons, as long as there is only one group of more than two consecutive colons. Thus
2001:2353:0000:0000:0000:0000:1428:57ab
2001:2353:0000:0000:0000::1428:57ab
2001:2353:0:0:0:0:1428:57ab
2001:2353:0::0:1428:57ab
2001:2353::1428:57ab
are all valid and mean the same thing, but
2001::25de::cade
is invalid.2001:2353:02de::0e13
is the same thing as
2001:2353:2de::e13
If the address is an IPv4 address in disguise, the last 32 bits may be written in decimal; thus ::ffff:192.168.89.9 is the same as
::ffff:c0a8:5909, but not the same as
::192.168.89.9 or
::c0a8:5909.
The ::ffff:1.2.3.4 format is called an IPv4-mapped address, and is deprecated. The ::1.2.3.4 format is an IPv4-compatible address.IPv6 deployment
Related IETF working groups
External links
References