The OID indicating the managed object to be checked. The OID must be: - the OID of an instance object: in this case the rule is applied to that object; - the OID of a columnar object (missing of the instance sub-identifier): in this case the rule is applied to all the instances of the columnar object. The validity of the OID is verified when the manager tries to activate the row, following these actions: - the agent should try to read the value of the object referenced by the OID (like a snmp get operation); if the value is read, the OID refers to a valid instance object and the type of the object should be registered inside the agent; - if the object is not available, then the agent should try to read the next object in the lexicographical order (like a snmp get next operation); if the OID returned is a child node of the checkRuleOid, then the latter is assumed to be a columnar object and the type of the object read is stored inside the agent; - if no object could be found or the OID returned is not a leaf of checkRuleOid, then an inconsistentValue error is return to the attempt of activating the row. When setting the OID of a columnar object, at least one instance object must exist at the moment of the activation of the row, so that the validity test of OID passes and the row is activated. If the OID references an instance object that is removed or become inaccessible after the row has been activated, then rule automatically fails with a severity equal to 4294967295. If the OID value references a columnar object and no instance exists after the first performance, then the rule doesn't fail.