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OID project

​​The ITU-T Study Group 17 OID Project assists users of object identifiers or OIDs (Rec. ITU-T X.660 and X.670 series) within and outside of ITU-T, and promotes the use of OIDs across a wide range of countries, companies and standards bodies. 

It is the continuation of a part of the common ASN.1 and OID project established in February 2001 by ITU-T Study Group 7 (now Study Group 17).

Objectives of the project

  • ​Provide assistance to ITU Member States that want to set up a national Registration Authority for OIDs in their country under arc {iso(1) member-body(2)} or arc {joint-iso-itu-t(2) country(16)};
  • Provide assistance to other study groups as well as to SDOs, consortia and fora with their use of OIDs;
  • Help the TSB in responding to requests they receive from users of the ITU web site regarding OIDs;
  • Develop any needed promotional material on OIDs;
  • Maintain a web-based OID repository of object identifiers and ensure that OIDs defined in ITU-T Recommendations are described in that repository.

Management of the Project

Olivier Dubuisson (Orange, France) has been appointed as Project Leader. The Project Leader in consultation with the SG17 Chairman and TSB manages decisions related to the operation of the ITU-T Project including the use of its name and resources. All such decisions are reported to each Plenary session of SG17. 

The Project Leader establishes a close working relationship with the SG17 management team and with the Operations & Planning Department and other parts of the TSB.

Background on OIDs and Registration Authorities

In an open and international world such as the one of telecommunications and information technologies, one often needs to be able to reference an "object" in a unique and universal way. Usually, an object is a class of information (for example, a file format), rather than an instance of such a class (for example, an individual file). 

Many standards define certain objects for which unambiguous identification is required. This is achieved by assignment of an object identifier (or OID) to an object in a way which makes the assignment available to interested parties. It is carried out by a Registration Authority. 

The naming structure that has been chosen is a tree structure that allows the identification of objects in a local or international context, without being limited either by the registration authority, nor by the number of objects they can register. (The naming pattern is therefore similar to the one of the Internet domains and subdomains.) Each new node is associated with a name (a word beginning with a lowercase letter) and a number that will be used for data transfers. An OID is semantically an ordered list of object identifier components (or arcs). 

Example: {joint-iso-itu-t(2) ds(5) attributeType(4) distinguishedName(49)} 

The registration tree is managed in a completely decentralized way (a node gives full power to its children). The OID Project has set up a repository that gathers information about a lot of OIDs (including all of those that are defined in any ITU-T Recommendation), but it is impossible to collect in one repository all allocated OIDs (particularly world-wide, and within companies). 

Supplementary information on operation of a country Registration Authority, and on known country Registration Authorities is available at

More background information on OIDs and Registration Authorities can be found in the final draft handbook “Object identifiers (OIDs) and their registration authorities” (TIES account needed) which is published in the six official UN languages and is available at


The OID Project has also been concentrating on a web-based repository of object identifiers (OIDs) and Registration Authorities as defined in the Rec. ITU-T X.660 & X.670 series. Orange, in close liaison with the ASN.1 Project, is running a publicly available repository (available at or​) that contains information about more than 1,700,000 OIDs

The OID Project also helps many countries that need to have a national OID arc for their companies under {iso(1) member-body(2)} or {joint-iso-itu-t(2) country(16)}, and to delegate the Registration Authority to their ISO National Body and/or ITU Member State.