Internet Protocol Address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol Suite for communication. Internet Protocol Address serves two main functions: host or network interface identification and location addressing.
Internet Protocol Version 4 (IPv4) defines an IP Address as a 32-bit number where Internet Protocol Version 6 (IPv6), using 128 bits for the IP address.
Internet Protocol Addresses are written and displayed in human-readable notations, such as 172.16.254.1 in IPv4, and 2001:db8:0:1234:0:567:8:1 in IPv6. The size of the routing prefix of the address is designated in CIDR notation by suffixing the address with the number of significant bits, e.g., 192.168.1.15/24, which is equivalent to the historically used subnet mask 255.255.255.0.
The IP address space is managed globally by the Internet Assigned Numbers Authority (IANA), and by five regional Internet registries (RIRs) responsible in their designated territories for assignment to local Internet registries, such as Internet Service Providers (ISPs), and other end users. IPv4 addresses were distributed by IANA to the RIRs in blocks of approximately 16.8 million addresses each, but have been exhausted at the IANA level since [2011]. Only one of the RIRs still has a supply for local assignments in Africa.
Internet Protocol Addresses are reserved for Private-Use Networks and are not globally unique.
However, IP addresses can also be written in three other formats: