IPv4 network addresses

As specified in the Internet Engineering Task Force (IETF) publication, RCF 791, the label v4 represents the fourth version of IP addressing (that is, IPv4). The IPv4, usually known as an IP address, is a logical element that consists of 32 bits and is organized into four octets (eight bits each), separated by a period. An IPv4 address has a size of four bytes, where each octet represents one byte. The total number of IPv4 addresses is 4,294,967,296. If each person in the world is assigned an IPv4 address, then it's apparent that there are more than 3 billion IPv4 addresses missing. That's why IPv6 network addresses were introduced.