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 The following usage specification applies to all Attributes of Normalized IODs unless superseded by a usage specification in a particular SOP Class Specification.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 Attribute Requirements

Mandatory: The SCU shall provide the Attribute with the command.
Optional: The SCU may or may not provide the Attribute with the command.
Not Allowed: The SCU shall not provide the Attribute with the command.

SCU Attribute Contents

Permitted: An Attribute with zero length is permitted.
Permitted: An Attribute with zero length is not permitted.

SCP Behavior

Mandatory: The SCP shall support receiving the Attribute with the command.
Mandatory with Default: The SCP shall support receiving the Attribute with the command. 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 with the command.
Not Allowed: The SCP shall not support receiving this Attribute with the command.

	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
-/-	Not Allowed	Not Permitted	Not Allowed

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".