[This is preliminary documentation and subject to change.]
An SNMP object identifier uniquely names an object and identifies its location within a Management Information Base (MIB) tree structure. Object identifiers are application-independent Abstract Syntax Notation One (ASN.1) data types that consist of a sequence of non-negative integers, or subidentifiers. Object identifiers must have a minimum of two subidentifiers and they must not exceed 128 subidentifiers.
The WinSNMP programming environment uses the smiOID structure to manage object identifiers. The format of the object identifier array in an smiOID structure is one subidentifier per array element.
The dotted numeric string representation of an object identifier separates its subidentifiers with periods; for example, "1.2.3.4.5.6".
For additional information, see The SNMP Management Information Base (MIB) and the relevant RFCs.