There are currently five RIRs:
- African Network Information Center (AfriNIC)
- Asia Pacific Network Information Centre (APNIC)
- American Registry for Internet Numbers (ARIN)
- Latin American and Caribbean Internet Addresses Registry (LACNIC), and
- Réseaux IP Européens (RIPE NCC).
The RIRs assign address blocks to Local Internet Registries (LIRs) or networks within their territories pursuant to each RIR's policy. Those networks, in turn, can assign blocks of addresses to smaller networks, or individual numbers to individual subscribers.
RIRs manage IP numbers as a public resource. When a Local Internet Registry allocates a number to an entity, it is giving that entity the ability to use that number; no property right is conferred to the recipient. IP numbers are allocated on a needs-basis pursuant to RIR policies; recipients pay fees which support the operation of the registries.