The Object Identifier (OID) is a concept defined in the Simple Network Management Protocol(SNMP).
The Object Identifier is the value used in certain Management Information Base( MIB) modules to uniquely identify specific SNMP objects. The OID identifier itself is a sequence of letters and digits used to uniquely identify the object.
In an Event Management Information Base (MIB), a network management system or the user can observe and trigger specific objects in response to specific events. This trigger, which can be triggered by preset levels or set filters, specifies the Object Identifier (OID) of the monitored object in the MIB database.