The Number Resource Organization (NRO) is an organisation that is comprised of the five regional Internet registries:
The Number Resource Organisation (NRO) was founded on the 24th of October, 2003. The NRO was founded when four Regional Internet Registries (AfriNIC was founded in 2005) signed a multilateral agreement to coordinate their activities and policies, and ultimately to provide a communal focal point for the Internet.
The Regional Internet Registries (RIRs) are responsible for distributing, managing and registering Internet numbers - most notable IP addressed (IPv4 and IPv6 addresses) - for their specific region. While Regional Internet Registries (RIRs) tend to occupy one of the five global continents, some registries cover a geographical region that covers two continents.
The NRO has a 'Number Council' which is comprised of three or four members from each of the five RIRs. The NRO Number Council is categorised as a 'supporting organisation' to ICANN, and will provide ICANN with suggestions on future Internet address policies; however, ICANN will have the "final say" on approving any recommendation made by the NRO Number Council.
The five Regional Internet Registries (RIRs) - and by extension, the Number Resource Organization (NRO) - are allocated their authority by the Internet Assigned Numbers Authority (IANA). IANA provides each of the RIRs with a large block of Internet resource numbers (IPv4 addresses, IPv6 addresses and Autonomous System Numbers) and the RIRs allot a smaller block of Internet resource numbers to a national organisation.
IANA is a department of ICANN, and ICANN was under contract to the US Department of Commerce until 2016. Therefore, the hierarchy of "power" and authority over the namespace (DNS and IP) of the Internet is as follows (2014):