Device on internet 

Every device on the Internet, such as a
computer or mobile telephone, must be
assigned an IP address for identification and location addressing in order to
communicate with other devices. With the
ever-increasing number of new devices
being connected to the Internet, the need
arose for more addresses than IPv4 is able
to accommodate. IPv6 uses a 128-bit address, allowing for 2128, or approximately 3.4×1038 addresses, or more than 7.9×1028 times as many as IPv4, which uses 32-bit addresses. IPv4
allows for only approximately 4.3 billion
addresses. The two protocols are not
designed to be interoperable, complicating the transition to IPv6. IPv6 addresses consist of eight groups of
four hexadecimal digits separated by colons, for example
2001:0db8:85a3:0042:1000:8a2e:0370:73
34.