The SCU shall use the N-ACTION primitive to request the SCP the safekeeping of a set of SOP Instances. The SOP Instances are referenced in the Action Information as specified in Table J.3-1. The Action Type ID shall be set to 1 specifying the request for storage commitment.
The SCU shall supply the Transaction UID Attribute (0008,1195) to uniquely identify each Storage Commitment Request. The value of the Transaction UID Attribute will be included by the SCP in the Storage Commitment Result (see Section J.3.3.1). Use of the Transaction UID Attribute allows the SCU to match requests and results which may occur over the same or different Associations.
The N-ACTION primitive shall contain the well-known Storage Commitment Push Model SOP Instance UID (defined in Section J.3.5) in its Requested SOP Instance UID parameter.
Note: In the usage described here, there is no explicit creation of a SOP Instance upon which an N-ACTION primitive may operate. Instead, the N-ACTION primitive operates upon a constant well-known SOP Instance. This SOP Instance is conceptually created during startup of each Storage Commitment Service Class SCP Application.
Upon receipt of a successful N-ACTION Response Status Code from the SCP, the SCU now knows that the SCP has received the N-ACTION request. Upon receipt of any other N-ACTION Response Status Code from the SCP, the SCU now knows that the SCP will not process the request and therefore will not commit to the storage of the SOP Instances referenced by the Storage Commitment Request. The actions taken by the SCU upon receiving the status is beyond the scope of this Standard. Upon receipt of a failure status, the Transaction UID is no longer active and shall not be reused for other transactions.
At any time after receipt of the N-ACTION-Response, the SCU may release the association on which it sent the N-ACTION-Request.
Notes: 1. Failure of storage commitment will be signaled via the N-EVENT-REPORT primitive.
2. In situations where the SOP Instance(s) are transferred via Media Interchange, the Storage Commitment Request may fail because the piece of Media containing the referenced SOP Instance(s) may not yet have been read. Attributes (0088,0130) File-Set ID and (0088,0140) File-Set UID may or may not be present in the case of Media Interchange. They may be provided to facilitate identification of the media containing the transferred SOP Instance(s) by the Storage Commitment SCP.