Different between IPV4 and IPv6
IPv4 was conceived in the early 1980s as a way of identifying individual connections to a computer network.
It is typically made up of 32 bits, written as 12 digits, e.g. 126.96.36.199.
That gives a maximum of around 4.3bn addresses.
However, the rapid growth in PCs, smartphones and other internet connected devices means those addresses are close to being used up, with an estimated 80 million still to be allocated.
IPv6 is a 128bit system, written in hexadecimal (base 16 counting using numbers and letters), e.g. 21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A.
The system gives a maximum of 340 undecillion possible addresses (1 undecillion = 10 followed by 35 zeros in the British numbering system).
The additional capacity, argue proponents of IPv6, will be needed to cater to the so-called "internet of things" where devices such as TVs, fridges and home heating systems are connected to the net.