Regional Internet Registries（RIR）的功能為管理、分配及註冊各區的IP位址與自治系統（autonomous system，AS）號碼等網路資源。目前全球共有5個RIR，分別為APNIC、ARIN、RIPE NCC、LACNIC及AFRINIC，彼此之間雖獨立運作，但亦會透過號碼資源組織（Number Resources Organization，NRO）相互合作及協調。
There are five Regional Internet Registries (RIRs) in the world. RIRs manage, distribute, and register Internet number resources (IPv4 and IPv6 address space and Autonomous System (AS) Numbers) within their respective regions.
NRO (2021). Regional Internet Registries. NRO.
While RIRs work independently within the regions they serve, they also cooperate and coordinate their activities with each other. Some of this work is done through the Number Resources Organization (NRO), which is a coordinating body that unites the five RIRs.
APNIC history (2021). History of the Regional Internet Registries. APNIC.