This Recommendation defines registration procedures of identification scheme defined by Recommendation ITU-T H.642.1 for 1LC value of 0001 2 . The identification scheme consists of First Level Code (1LC), Second Level Code (2LC), Class and elements such as Third Level Code (3LC), and Fourth Level Code (4LC). 2LC is pre-assigned to ITU Member States, and then 3LC is allocated by the registrant of 2LC which is called second level RA. The mechanism is meant for distributed RA hierarchy.