IPv4 Addressing & Subnetting by Arash Deljoo

Internet Protocol version 4 (IPv4) is the fourth version of the standard that routes Internet traffic and other packet-switched networks introduced in 1982 by the Internet Engineering Task Force (IETF). IPv4 is the most widely used version of the protocol despite the limitations of its 32-bit address space. With slightly less than 4.3 billion available unique addresses, the available number of addresses quickly began to run out. With some clever ingenuity over the years that extended the life of the protocol, the pool of available addresses didn’t dry up until 2011.

An Internet Protocol address is a unique identifier for devices connected to a network. The unique identifier makes it possible for devices to find and communicate with each other. Initially, the main types of devices that required an IP address included network devices, such as computers, servers, routers, and printers. However, with the Internet of Things, the list includes cell phones, televisions, refrigerators, automobiles, light bulbs, or anything else capable of receiving or exchanging information over a network.

An IPv4 address is a series of four eight-bit binary numbers separated by a decimal point. Although you may use any numbering system to represent a unique 32-bit number, most commonly you see IP addresses expressed in dot-decimal notation.