G.4.2.4.3 Association Initiation Policy
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##### G.4.2.4.3 Association Initiation Policy

MOVE-SCU attempts to initiate a new association when the results of the FIND-SCU indicate matching Hanging Protocol Instances to retrieve.

###### G.4.2.4.3.1 Activity - Retrieve From Remote AE

###### G.4.2.4.3.1.1 Description and Sequencing of Activities

A single attempt will be made to retrieve Hanging Protocol Instances from the remote AE. If the retrieve fails, for whatever reason, no retry will be performed.

###### G.4.2.4.3.1.2 Proposed Presentation Contexts

Table G.4.2-24. Proposed Presentation Contexts for MOVE-SCU and Retrieve From Remote AE

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name List | UID List
See Table G.4.2-20 | See Table G.4.2-20 | Implicit VR Little Endian | 1.2.840.10008.1.2 | SCP | None
Explicit VR Little Endian | 1.2.840.10008.1.2.1

MOVE-SCU will propose multiple Presentation Contexts, one for each of the supported Transfer Syntaxes, and an additional Presentation Context with all of the supported Transfer Syntaxes, in order to determine which Transfer Syntaxes the remote SCP supports, and which it prefers.

###### G.4.2.4.3.1.2.1 Extended Negotiation

No extended negotiation is performed.

###### G.4.2.4.3.1.3 SOP Specific Conformance

###### G.4.2.4.3.1.3.1 SOP Specific Conformance to C-FIND SOP Classes

MOVE-SCU provides standard conformance to the supported C-MOVE SOP Class.

No CANCEL requests are ever issued.

The retrieval is performed from the AE that was specified in the Retrieve AE attribute returned from the query performed by FIND-SCU. The instances are retrieved to the current application's local database by specifying the destination as the AE Title of the STORE-SCP AE of the local application. This implies that the remote C-MOVE SCP must be preconfigured to determine the presentation address corresponding to the STORE-SCP AE. The STORE-SCP AE will accept storage requests addressed to it from anywhere, so no pre-configuration of the local application to accept from the remote AE is necessary (except in so far as it was necessary to configure FIND-SCU).

Table G.4.2-25. Request Identifier for MOVE-SCU

Name | Tag | Request Key
--- | --- | ---
Hanging Protocol
SOP Instance UID | (0008,0018) | List of UIDs

###### G.4.2.4.3.1.3.2 Presentation Context Acceptance Criterion

MOVE-SCU does not accept associations.

###### G.4.2.4.3.1.3.3 Transfer Syntax Selection Policies

MOVE-SCU prefers explicit Transfer Syntaxes. If offered a choice of Transfer Syntaxes in the accepted Presentation Contexts, it will apply the following priority to the choice of Presentation Context to use for the C-MOVE operation:

1. first encountered explicit Transfer Syntax,

2. default Transfer Syntax.

###### G.4.2.4.3.1.3.4 Response Status

MOVE-SCU will behave as described in the Table below in response to the status returned in the C-MOVE response command message(s).

Table G.4.2-26. Response Status for MOVE-SCU and Retrieve From Remote AE Request

Service Status | Further Meaning | Status Codes | Related Fields | Behavior
--- | --- | --- | --- | ---
Refused | Out of Resources - Unable to calculate number of matches | A701 | (0000,0902) | Retrieval is terminated
| Out of Resources - Unable to perform sub-operations | A702 | (0000,1020) (0000,1021) (0000,1022) (0000,1023) | Retrieval is terminated
| Move Destination unknown | A801 | (0000,0902) | Retrieval is terminated
Failed | Identifier does not match SOP Class | A900 | (0000,0901) (0000,0902) | Retrieval is terminated
| Unable to process | Cxxx | (0000,0901) (0000,0902) | Retrieval is terminated
Cancel | Sub-operations terminated due to Cancel Indication | FE00 | (0000,1020) (0000,1021) (0000,1022) (0000,1023) | Retrieval is terminated (should never occur, since cancels never issued)
Warning | Sub-operations Complete - One or more Failures | B000 | (0000,1020) (0000,1022) (0000,1023) | Retrieval is terminated
Success | Sub-operations Complete - No Failures | 0000 | (0000,1020) (0000,1021) (0000,1022) (0000,1023) | Retrieval is terminated
Pending | Sub-operations are continuing | FF00 | (0000,1020) (0000,1021) (0000,1022) (0000,1023) | Retrieval continues

###### G.4.2.4.3.1.3.5 Sub-Operation Dependent Behavior

Since the C-MOVE operation is dependent on completion of C-STORE sub-operations that are occurring on a separate association, the question of failure of operations on the other association(s) must be considered.

MOVE-SCU completely ignores whatever activities are taking place in relation to the STORAGE-SCP AE that is receiving the retrieved instances. Once the C-MOVE has been initiated it runs to completion (or failure) as described in the C-MOVE response command message(s). There is no attempt by MOVE-SCU to confirm that instances have actually been successfully received or locally stored.

Whether or not completely or partially successfully retrievals are made available in the local database to the user is purely dependent on the success or failure of the C-STORE sub-operations, not on any explicit action by MOVE-SCU.

Whether or not the remote AE attempts to retry any failed C-STORE sub-operations is beyond the control of MOVE-SCU.

If the association on which the C-MOVE was issued is aborted for any reason, whether or not the C-STORE sub-operations continue is dependent on the remote AE; the local STORAGE-SCP will continue to accept associations and storage operations regardless.

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