5.4.2 Use of Attributes in Normalized Services

5.4.2 Use of Attributes in Normalized Services (Current)
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Modules and their usage in Composite IODs are defined in PS3.3. Normalized IODs are also constructed from Modules but usage is specified on an Attribute basis in this Part of the DICOM Standard. The following usage specification applies to all Attributes of Normalized IODs unless superseded by a usage specification in a particular SOP Class Specification.

The term ‘receive’ means the following: the value shall be stored; under certain circumstances (e.g. coercion) the value returned may have changed.

5.4.2.1 DIMSE Service N-CREATE, N-SET, N-ACTION

The following Requirements apply when specifying the use of DIMSE services N-CREATE, N-SET, N-ACTION.

The convention used in the table below are as follows:

SCU Behavior

Mandatory: The SCU shall provide the Attribute.
Optional: The SCU may or may not provide the Attribute.
Undefined: The SCU's usage of the Attribute is undefined.

SCP Behavior

Mandatory: The SCP shall support receiving the Attribute.
Mandatory with Default: The SCP shall support receiving the Attribute. Upon receiving zero-length values, the SCP shall assign values as defined by the specification of the Service Class.
Optional: The SCP may or may not support receiving the Attribute.
Undefined: The SCP’s support of the Attribute is undefined.

	SCU		SCP
Usage	Requirement	Zero Length	Requirement
1/1	Mandatory	Not Permitted	Mandatory
2/1	Mandatory	Permitted	Mandatory with Default
2/2	Mandatory	Permitted	Mandatory
3/1	Optional	Not Permitted	Mandatory
3/2	Optional	Not Permitted	Optional
3/3	Optional	Not Permitted	Optional
-/-	Undefined	Undefined	Undefined

If the SCU does not provide an Attribute that is Mandatory for the SCU, the SCP shall respond with a Failure Status Code of 0120H "Missing Attribute".

If the SCU provides a zero-length value for a Mandatory Attribute when zero length is not permitted, the SCP shall respond with a Failure Status Code of 0121H "Missing Attribute Value".