| DICOM PS3.7 2024d - Message Exchange |
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The C-FIND procedures are initiated by the invoking DIMSE Service User issuing a C-FIND request primitive. On receipt of the C-FIND request primitive the DIMSE-C protocol machine shall:
On receipt of a Message conveying a C-FIND-RQ the DIMSE-C protocol machine shall issue a C-FIND indication primitive to the performing DIMSE Service User.
The DIMSE-C protocol machine shall:
accept zero or more C-FIND response primitives containing the status of Pending, issued by the performing DIMSE Service User, followed by a single C-FIND response primitive containing the final status
for each C-FIND response primitive containing the Pending status the DIMSE-C protocol machine shall:
for the C-FIND response primitive containing the final status the DIMSE-C protocol machine shall:
On receipt of a Message conveying a C-FIND-RSP the DIMSE-C protocol machine shall:
if the Message indicates the status of Pending, issue a C-FIND confirmation primitive to the invoking DIMSE Service User with a Pending status
if the Message indicates a final status, issue a C-FIND confirmation primitive to the invoking DIMSE Service User with a final status, thus completing the C-FIND procedure
The C-FIND procedures can be canceled at any time by the invoking DIMSE Service User. This is accomplished by the invoking DIMSE Service User issuing a C-CANCEL request primitive.
The performing DIMSE Service User may return a C-FIND-RSP with the status of Failed or Refused before the complete C-FIND-RQ request Message has been completely transmitted by the invoking DIMSE Service User (this is called an early failed response). Upon receipt of this Failed or Refused C-FIND-RSP the invoking DIMSE Service User may terminate the Message before it is completely sent (i.e., set the Last Fragment bit to 1 in a Data PDV for this Message, see Annex F). Following this, it may invoke another operation or notification. It is a protocol violation for an invoking DIMSE Service User to set the Last Fragment bit to 1 before a C-FIND-RQ Message has been completely transmitted if it has not received a Failed or Refused C-FIND-RSP to that request.
When an Association is operating in asynchronous mode, it is possible for an invoking DIMSE Service User to transmit several Messages before a response. Therefore, while sending a Message it may receive a response to a previously transmitted Message. In this case this response is not an early failed response because the related Message has already been sent.
| DICOM PS3.7 2024d - Message Exchange |
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