IP Address

An IP address, or Internet Protocol Address is the unique number given to every computer connected to the Internet. This number allows users and other computers to find each other.

In the IPv4 scheme, IP addresses consist of 4 bytes, allowing for a full range of 4,294,967,295 unique addresses. Represented visually these addresses consist of four numbers which are between 0 and 255, separated by periods, such as 132.42.45.101.

In IPv6, IP addresses consist of 16 bytes, allowing for a theoretically total of 340,282,366,920,938,463,463,374,607,431,768,211,456 unique addresses. The literal representation is done in blocks of 16 bits written in hex, separated by colon, such as 2001:db8:1:2:3:4:5:6 (zeros at the left don't need to be written). A longer address, with many zeros can get compressed; for example ff02:0:0:0:0:0:0:1 will become ff02::1. In the case of an address with multiple blocks of zeros, e.g. ff02:0:0:0:12:0:0:1, only the longer block is compressed. That is, ff02:0:0:0:12:0:0:1 becomes ff02::12:0:0:1 rather than ff02:0:0:0:12::1.

Internet Protocol
IPv4 - the most widely deployed version of the Internet Protocol. Conversion costs (staff time and expertise especially) have slowed conversion to IPv6. But the need for advanced functions is lately provided an incentive to make the switch.
IPv6 - the most recent version of the Protocol. Deployment started around 2003 in some big operators. Initial deployment was slow. However, the exhaustion of available IPv4 addresses, combined with the rapid expansion of the number of Internet connected devices, has driven more rapid expansion recently.

See also