# IPV4

Internet Protocol version 4 (IPv4), also known as Internet Protocol Version 4, is the fourth revision of the Internet protocol in development and the first widely deployed version of the protocol. IPv4 is the core of the Internet and the most widely used version of the Internet protocol, followed by IPv6, which was still in the early stages of deployment when the IANA IPv4 address was exhausted in 2011.

IPv4 was described in the IETF's RFC 791 released in September 1981, which replaced the RFC 760 released in January 1980.

IPv4 is a connectionless protocol that operates on a link layer (such as Ethernet) that uses packet switching. This protocol does its best to deliver the packets, meaning that it does not guarantee that any packet will reach its destination, nor that all packets will arrive in the correct order without repetition. These aspects are handled by upper-layer transport protocols such as Transmission Control Protocol.

On November 26, 2019, all 4.3 billion IPv4 addresses in the world were allocated, meaning that there are no more IPv4 addresses to assign to ISPs and other large network infrastructure providers.

# IPV6

Internet Protocol version 6 (English: Internet Protocol version 6, abbreviated: IPv6) is the latest version of the Internet Protocol, used as the protocol for the Internet. It was used to replace IPv4 mainly to solve the IPv4 address exhaustion problem, but it also improved IPv4 in many other ways.

IPv6 was designed to replace IPv4, but while IPv4 has long dominated Internet traffic, its use has grown slowly. In December 2019, the percentage of users using Google services over IPv6 exceeded 30 percent for the first time.