A Regional Internet Registry (RIR) is an organization that oversees the registration and allocates IP addresses in a certain region of the world. Namely there are currently 4 registries, all overseen by the Internet Assigned Numbers Authority (IANA):

• American Registry for Internet Numbers (ARIN) [1] for North America
• RIPE Network Coordination Centre (RIPE NCC) [2] for Europe
• Asia-Pacific Network Information Centre (APNIC) [3] for Asia and the Pacific region
• Latin American and Caribbean Internet Addresses Registry (LACNIC) [4] for Latin America and the Caribbean region

Currently Africa is divided between the four existing RIRs, though there is an emerging registry for the region, AfriNIC. It has not yet been fully ratified by IANA, though looks likely to be so in the near future.

• AfriNIC for Africa

Collectively the RIRs form part of the Numbers Resource Organization [5] formed as a body to represent their collective interests and ensure that policy statements are coordinated globally.

IANA delegates the allocation of IPv4 addresses to RIRs in large chunks (typically /8 or more at a time), and the RIRs then follow their own policies for address allocation. They typically further delegate address assignment to Internet Service Providers in small chunks, with the smallest currently being /22.

The RIRs also allocate IPv6 addresses and Autonomous system numbers.