17. IPV6

17.1 Overview Formerly named IPng (next gen)

for replacing the 32-bit addressing scheme or the current IPv4 implementation which is inadequate to meet the demand of Internet growth

IPv6 increases the no of bits from 32 to 128 which provides more than enough globally unique IP addresses for all networked devices in the world

17.2 IPv6 Addressing Representation

17.2.1 Normal IPv6 format

since no of bits in IPv6 is four times the number of bits being used by IPv4, the presentation format of IPv6 uses 32 hexadecimal digits (十六進位數值，每個代表4 bits) Every 4 hexadecimal digits (16 bits i.e. two octets) are grouped togather as a field and separated from other fields by colons(:) in the format:

XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX

The following shows an example of an IPv6 addess: 2001:0DB8:0000:0210:00DC:BA98:7654:3210

However, leading "0" in each group can be omitted for easier reading: 2001:DB8:0:210:DC:BA98:7654:3210

17.2.2 Compressed IPv6 Format

Moreover since it is common for IPv6 addresses to contain successive(連接的) hexadecimal fields of zeros, in order to make IPv6