is the organization responsible for global coordination of the Internet Protocol addressing systems.
Currently there are two types of Internet Protocol (IP) addresses in active use: IP version 4 (IPv4) and IP version 6 (IPv6).
- The IPv4 protocol was initially deployed on 1 January 1983. IPv4 addresses are 32-bit numbers often expressed as 4 octets in "dotted decimal" notation (for example, 220.127.116.11).
- The IPv6 protocol deployment began in 1999. IPv6 addresses are 128-bit numbers and are conventionally expressed using hexadecimal strings (for example, 2001:b80d:582:33ae::92).
Both IPv4 and IPv6 addresses are generally assigned in a hierarchical manner. Users are assigned IP addresses by Internet service providers (ISPs). ISPs obtain allocations of IP addresses from a local Internet registry (LIR) or National Internet Registry (NIR), or from their appropriate Regional Internet Registry (RIR):
| Registry ||Area Covered|
|ARIN||North America Region|
|LACNIC||Latin America and some Caribbean Islands|
|RIPE NCC||Europe, the Middle East, and Central Asia|
The IANA's role is to allocate IP addresses from the pools of unallocated addresses to the RIRs according to their needs as described by global policy and to document protocol assignments made by the IETF. When an RIR requires more IP addresses for allocation or assignment within its region, the IANA makes an additional allocation to the RIR. IANA generally doesn't assign allocations directly to ISPs or end users except in specific circumstances, such as allocations for multicast addresses or other protocol specific needs.