IPv6 addressing

IPv6 Addressing
? The address depletion of IPv4 protocol was one of the major reason for developing IPv6
protocol.
? An IPv6 address is 128 bits or 16 bytes (octet) long . The address length in IPv6 is four times
of the length address in IPv4.
Notations
Several notations have been proposed to represent IPv6 addresses when they are handled by
humans:
Dotted-Decimal Notation
This notation is rarely used except partially as we see shortly.
221.14.65.11.105.45.170.34.12.234.18.0.14.0.115.255
Colon Hexadecimal Notation
To make addresses more readable, IPv6 specifies colon hexadecimal notation.
Although the IP address, even in hexadecimal format, is very long, many of the digits are zeros. In
this case, we can abbreviate the address. The leading zeros of a section can be omitted. Using this
form of abbreviation, 0074 can be written as 74, 000F as F, and 0000 as 0. Note that 3210 cannot be
abbreviated.
Further abbreviation, often called zero compression, can be applied to colon hex notation if there
are consecutive sections consisting of zeros only. We can remove all the zeros altogether and replace
them with a double semicolon.
Note that this type of abbreviation is allowed only once per address. If there are two runs of zero
sections, only one of them can be compressed.
Mixed Representation
This is appropriate during the transition period in which an IPv4 address is embedded in an IPv6
address (as the rightmost 32 bits).