3.9.1 Presence

Not all allowed attributes need to be present in every instance of the object type. The table below shows how presence is defined for an attribute. The same attribute name may have a different presence defined in different object types. For example “status:” is mandatory in an inetnum object, but generated in an aut-num object.

Types of ‘presence' of an Attribute




You must include at least one instance of this attribute in all objects of this type.


This attribute is optional in the objects of this type and you can leave it out. If you choose to include this attribute then the value must also be included.


The syntax rules define this attribute as optional. However, additional business rules require this attribute under some circumstances.


These attributes are generated if you leave them out. If you include the attribute and provide the value, it may be replaced by a value determined by the software.

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