Reference record for OID 0

Subsequent OIDs identify ITU-T Recommendations (not jointly published with ISO/IEC) and ITU members.

This arc is also called ccitt(0) to recall that CCITT used to be an organization independent from ITU-T.

Identifier itu-r was added by ITU-T Study Group 17 in March 2004 (and was ratified by ISO/IEC JTC 1/SC 6 in Sep 2005). It can only be used as a 'NameAndNumberForm' (that is, followed by number 5 between parentheses) for OIDs that commence with {itu-r(0) r-recommendation(5)} (see Rec. ITU-T X.680 | ISO/IEC 9834-1, clause A.5, for more details on this specific case). Consequently Unicode label ITU-R can only be used for "OID-IRIs" that designate OIDs under the {itu-r(0) r-recommendation(5)} arc.

Operation is in accordance with Rec. ITU-T X.660 | ISO/IEC 9834-1 and is under the guidance of ITU-T Study Group 17.

All decisions related to subsequent arcs, other than the assignment of additional secondary identifiers to top-level arc 0 (see Rec. ITU-T X.660 | ISO/IEC 9834-1, clause A.5), will be recorded ad amendments to Rec. ITU-T X.660 | ISO/IEC 9834-1 (such changes to the joint ITU-T | ISO/IEC text will be regarded as editorial by ISO).

From Rec. ITU-T X.660 | ISO/IEC 9834-1, "the top-level arcs are restricted to three arcs numbered 0 to 2; and the arcs beneath root arcs 0 and 1 are restricted to forty arcs numbered 0 to 39. This enables optimized encodings to be used in which the values of the top two arcs for all arcs under top-level arcs 0 and 1 encode in a single octet in an object identifier encoding (see the Rec. ITU-T X.690 series | ISO/IEC 8825 multi-part Standard).