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ASN.1 OBJECT IDENTIFIER tag: 06

The ASN.1 OBJECT IDENTIFIER type is used when you need to provide a unique identifier (for example, for a module).

The possible values of OBJECT IDENTIFIERs are defined by reference to an object identifier tree beginning with three numbered branches coming from the root: branch 0, assigned to ITU-T (formerly CCITT), branch 1, assigned to ISO, and branch 2, a joint ISO-ITU-T branch. Below each of these branches are other numbered branches. This hierarchical organization allows unique names to be assigned to any number of objects.

Example

OperationID ::= OBJECT IDENTIFIER

The following example shows a basic structure: a list of components, demarcated by brackets, containing a named number, an identifier, and a positive integer value. Like all OBJECT IDENTIFIERs, it describes a unique path from the root of the object identifier tree to a leaf; that path is reflected in this value.

ftam1 OBJECT IDENTIFIER ::= {
          iso standard 8571 abstract-syntax(2)
          ftam-pci(1)
}

In the following example, the value ftamRoot is defined, describing the path to the root of the FTAM-specific part of the object identifier tree. That value is then used within the definition of the value ftam3. This notation provides a shorthand way of referring to several adjacent components in the tree.

ftamRoot OBJECT IDENTIFER ::= { 1 0 8571 }
ftam3   OBJECT IDENTIFIER ::= { ftamRoot abstract-syntax(2) ftam-pci(1) }
OBJECT IDENTIFIER encoding example
Name2 ::= OBJECT IDENTIFIER
ftam2 Name2 ::= { 1 0 8571 2 1 }
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In BER, the OBJECT IDENTIFIER type value defined in the example above is encoded as follows:

06 05 28C27B0201

Constraints

The OBJECT IDENTIFIER type can be constrained by a single value.

Related Topics