IPv4
Internet Protocol version 4 (IPv4) is the fourth iteration of the Internet Protocol (IP), which is a set of rules that govern the format of data sent over the internet or other networks. IPv4 is responsible for identifying devices on a network and routing traffic between them. It was the first version of the protocol to be widely deployed, and it is currently the most prevalent protocol used to connect devices to the internet.
IPv4 uses 32-bit (four-byte) addresses, which limits the address space to 4,294,967,296 (2^32) possible unique addresses. However, due to the way the addresses are allocated and reserved for special purposes, the number of available public addresses is fewer than the theoretical maximum. The addresses are typically written in dot-decimal notation, which consists of four octets of the address expressed individually in decimal and separated by periods, for example, 192.0.2.146[1][2][3].
Despite its widespread use, IPv4 has several limitations, most notably the exhaustion of the address space due to the increasing number of devices connected to the internet. This limitation has led to the development and gradual deployment of its successor, IPv6, which uses 128-bit addresses to provide a vastly larger address space[1][2][3].
IPv4 is a connectionless protocol and operates on a best-effort delivery model, meaning it does not guarantee delivery, proper sequencing, or avoidance of duplicate delivery. These aspects are handled by an upper-layer protocol, such as the Transmission Control Protocol (TCP). IPv4 also supports various types of addresses, such as unicast, broadcast, and multicast, which are used for different types of network communication[1][2].
The transition from IPv4 to IPv6 has been slow due to the need for backward compatibility and the challenges of changing the vast infrastructure of the internet. However, IPv6 is increasingly being adopted to accommodate the growing number of internet-connected devices and to overcome the limitations of IPv4[1][2][3].
Citations:
[1] https://en.wikipedia.org/wiki/Internet_Protocol_version_4
[2] https://www.geeksforgeeks.org/what-is-ipv4/
[3] https://bluecatnetworks.com/glossary/what-is-ipv4/
[4] https://www.techopedia.com/definition/5367/internet-protocol-version-4-ipv4
[5] https://www.cloudns.net/blog/what-is-ipv4-everything-you-need-to-know/
[6] https://www.uptrends.com/what-is/ipv4
[7] https://www.ibm.com/docs/en/zos/2.3.0?topic=ipv6-internet-protocol-version-4-ipv4