NRO

The Number Resource Organization is an umbrella coordination group for the RIRs.

The NRO has a number of RDAP extensions specific to RIRs all specified in one document:

• NRO RDAP Profile v0
• NRO RDAP Profile ASN Flat v0
• NRO RDAP Profile ASN Hierarchical V0

In addition, the NRO defines an extension for expressing IP address CIDR blocks in RDAP called cidr0.

Finally, there is an extension specific to ARIN for representing the originating autonomous system number of an IP network: arin_originas0.