URNs in the OGF namespace take the form urn:ogf:<snid>:<subnamespace-specific-string>.
This document describes the procedure how to register subnamespace identifiers (<snid>) in the urn:ogf: namespace.

(Note: this accompanies the document draft-dijkstra-urn-ogf that merely delegates the urn:ogf prefix to the OGF, and 
which should be published by the IETF).