IPv1 (Internet Protocol version 1) does not exist as a protocol. The first version of the Internet Protocol (IP) was actually IPv4, which was introduced in 1983 and is still widely used today.

IPv4 uses a 32-bit address format, which provides approximately 4.3 billion unique addresses. However, with the growth of the internet and the increasing number of devices that require IP addresses, the available IPv4 addresses are becoming increasingly scarce.

To address this issue, a new version of the Internet Protocol, IPv6, was developed. IPv6 uses a 128-bit address format, which provides an almost limitless number of unique addresses. IPv6 was introduced in 1998 and is gradually being adopted to replace IPv4.