IPv4 vs. IPv6 Internet Protocol (IP) is a global communications standard used for linking devices together. It defines how computers communicate over a network. The primary purpose of an IP address is to uniquely identify a node at the Network Layer. Every Internet connected device, computer, smartphone, smart TV, etc. needs a unique IP address. The explosive growth in mobile devices including mobile phones, notebook computers, and wireless handheld devices has created a need for a large number of additional IP addresses. There are currently two versions: IP version 4 (IPv4) and IP version 6 (IPv6). IPv4 is the 4th version of the Internet Protocol. It is the most commonly deployed OSI Layer 3 (Network layer) protocol. IPv4 has a 32 bit address space and consists of 2 32 or approximately 4.3 billion possibile IPv4 addresses. IPv4 was formally defined by the Internet Engineering Task Force (IETF) in September 1981 as RFC-791. IPv6 is the next generation of the Internet Protoc