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
http://www.oid-info.com/doc/country-OIDs.htm.
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
http://www.itu.int/pub/T-HDB-LNG.4-2010.