B.4.2 AE Specifications
Prev | B.4 Networking | Next

### B.4.2 AE Specifications

#### B.4.2.1 Storage Application Entity Specification

##### B.4.2.1.1 SOP Classes

EXAMPLE-INTEGRATED-MODALITY provides Standard Conformance to the following SOP Classes:

Table B.4.2-1. SOP Classes for AE Storage

SOP Class Name | SOP Class UID | SCU | SCP
--- | --- | --- | ---
X-Ray Radiofluoroscopic Image Storage | 1.2.840.10008.5.1.4.1.1.12.2 | Yes | No
Grayscale Softcopy Presentation State Storage | 1.2.840.10008.5.1.4.1.1.11.1 | Yes | No
Storage Commitment Push Model | 1.2.840.10008.1.20.1 | Yes | No
Verification | 1.2.840.10008.1.1 | No | Yes

##### B.4.2.1.2 Association Policies

###### B.4.2.1.2.1 General

The DICOM standard application context name for DICOM 3.0 is always proposed:

Table B.4.2-2. DICOM Application Context for AE Storage

Application Context Name | 1.2.840.10008.3.1.1.1

###### B.4.2.1.2.2 Number of Associations

EXAMPLE-INTEGRATED-MODALITY initiates one Association at a time for each destination to which a transfer request is being processed in the active job queue list. Only one job will be active at a time, the other remains pending until the active job is completed or failed.

Table B.4.2-3. Number of Associations Initiated for AE Storage

Maximum number of simultaneous Associations | 1 (configurable)

EXAMPLE-INTEGRATED-MODALITY accepts Associations to receive N-EVENT-REPORT notifications for the Storage Commitment Push Model SOP Class.

Table B.4.2-4. Number of Associations Accepted for AE Storage

Maximum number of simultaneous Associations | 5 (configurable)

###### B.4.2.1.2.3 Asynchronous Nature

EXAMPLE-INTEGRATED-MODALITY does not support asynchronous communication (multiple outstanding transactions over a single Association).

Table B.4.2-5. Asynchronous Nature as a SCU for AE Storage

Maximum number of outstanding asynchronous transactions | 1

###### B.4.2.1.2.4 Implementation Identifying Information

The implementation information for this Application Entity is:

Table B.4.2-6. DICOM Implementation Class and Version for AE Storage

Implementation Class UID | 1.xxxxxxx.yyy.etc.ad.inf.usw
Implementation Version Name | EXINTMOD_01

##### B.4.2.1.3 Association Initiation Policy

###### B.4.2.1.3.1 Activity - Send Images

###### B.4.2.1.3.1.1 Description and Sequencing of Activities

A user can select images and presentation states and request them to be sent to multiple destinations (up to 3). Each request is forwarded to the job queue and processed individually. When the "Auto-send" option is active, each marked instance or marked set of instances stored in database will be forwarded to the network job queue for a pre-configured auto-send target destination. Which instances will be automatically marked and the destination where the instances are automatically sent to can be configured. The "Auto-send" is triggered by the Close Patient user application.

The Storage AE is invoked by the job control interface that is responsible for processing network archival tasks. The job consists of data describing the instances marked for storage and the destination. An internal daemon process triggered by a job for a specific network destination initiates a C-STORE request to store images. If the process successfully establishes an Association to a remote Application Entity, it will transfer each marked instance one after another via the open Association. Status of the transfer is reported through the job control interface. Only one job will be active at a time. If the C-STORE Response from the remote Application contains a status other than Success or Warning, the Association is aborted and the related Job is switched to a failed state. It can be restarted any time by user interaction or, if configured, by automated retry.

The Storage AE attempts to initiate a new Association in order to issue a C-STORE request. If the job contains multiple images then multiple C-STORE requests will be issued over the same Association.

If the Remote AE is configured as an archive device the Storage AE will, after all images and presentation states have been sent, transmit a single Storage Commitment request (N-ACTION) over the same Association. Upon receiving the N-ACTION response the Storage AE will delay releasing the Association for a configurable amount of time. If no N-EVENT-REPORT is received within this time period the Association will be immediately released (i.e., notification of Storage Commitment success or failure will be received over a separate association). However, the Storage AE is capable of receiving an N-EVENT-REPORT request at any time during an association provided a Presentation Context for the Storage Commitment Push Model has been successfully negotiated (i.e., the N-ACTION is sent at the end of one association and the N-EVENT-REPORT is received during an association initiated for a subsequent send job or during an association initiated by the Remote AE for the specific purpose of sending the N-EVENT-REPORT).

Figure B.4.2-1. Sequencing of Activity - Send Images

A possible sequence of interactions between the Storage AE and an Image Manager (e.g., a storage or archive device supporting the Storage and Storage Commitment SOP Classes as an SCP) is illustrated in Figure B.4.2-1:

1. The Storage AE opens an association with the Image Manager

2. An acquired RF image is transmitted to the Image Manager using a C-STORE request and the Image Manager replies with a C-STORE response (status success).

3. A GSPS instance is transmitted to the Image Manager using a C-STORE request and the Image Manager replies with a C-STORE response (status success).

4. Another acquired RF image is transmitted to the Image Manager using a C-STORE request and the Image Manager replies with a C-STORE response (status success).

5. Another GSPS instance is transmitted to the Image Manager using a C-STORE request and the Image Manager replies with a C-STORE response (status success).

6. An N-ACTION request is transmitted to the Image Manager to obtain storage commitment of previously transmitted RF images and GSPS instances. The Image Manager replies with a N-ACTION response indicating the request has been received and is being processed.

7. The Image Manager immediately transmits an N-EVENT-REPORT request notifying the Storage AE of the status of the Storage Commitment Request (sent in step 6 using the N-ACTION message). The Storage AE replies with a N-EVENT-REPORT response confirming receipt. The Image Manager could send this message at any time or omit it entirely in favor of transmitting the N-EVENT-REPORT over a separate dedicated association (see note).

8. The Storage AE closes the association with the Image Manager.

### Note

Many other message sequences are possible depending on the number of images and GSPS instances to be stored, support for Storage Commitment and when the SCP sends the N-EVENT-REPORT. The N-EVENT-REPORT can also be sent over a separate association initiated by the Image Manager (see Section B.4.2.1.4.1 on Activity - Receive Storage Commitment Response).

###### B.4.2.1.3.1.2 Proposed Presentation Contexts

EXAMPLE-INTEGRATED-MODALITY is capable of proposing the Presentation Contexts shown in the following table:

Table B.4.2-7. Proposed Presentation Contexts for Activity Send Images

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name List | UID List
X-Ray Radio Fluoroscopic Image Storage | 1.2.840.10008.5.1.4.1.1.12.2 | Implicit VR Little Endian Explicit VR Little Endian | 1.2.840.10008.1.2 1.2.840.10008.1.2.1 | SCU | None
Grayscale Softcopy Presentation State Storage | 1.2.840.10008.5.1.4.1.1.11.1 | Implicit VR Little Endian Explicit VR Little Endian | 1.2.840.10008.1.2 1.2.840.10008.1.2.1 | SCU | None
Storage Commitment Push Model | 1.2.840.10008.1.20.1 | Implicit VR Little Endian Explicit VR Little Endian | 1.2.840.10008.1.2 1.2.840.10008.1.2.1 | SCU | None

Presentation Contexts for X-Ray Radio Fluoroscopic Image Storage or Grayscale Softcopy Presentation State Storage will only be proposed if the Send Job contains instances for these SOP Classes.

A Presentation Context for the Storage Commitment Push Model will only be proposed if the Remote AE is configured as an archive device.

###### B.4.2.1.3.1.3 SOP Specific Conformance Image & Pres State Storage SOP Classes

All Image & Presentation State Storage SOP Classes supported by the Storage AE exhibit the same behavior, except where stated, and are described together in this section.

If X-Ray Radio Fluoroscopic Image Storage SOP Instances are included in the Send Job and a corresponding Presentation Context is not accepted then the Association is aborted using AP-ABORT and the send job is marked as failed. The job failure is logged and reported to the user via the job control application.

If Grayscale Softcopy Presentation State Storage SOP Instances are included in the Send Job and a corresponding Presentation Context cannot be negotiated then Grayscale Softcopy Presentation State Storage SOP Instances will not be sent and a warning is logged. Any remaining Image Storage SOP Instances included in the Send Job will be transmitted. Failure to negotiate a Presentation Context for Grayscale Softcopy Presentation State Storage does not in itself cause the Send Job to be marked as failed. The behavior of Storage AE when encountering status codes in a C-STORE response is summarized in the Table below:

Table B.4.2-8. Storage C-STORE Response Status Handling Behavior

Service Status | Further Meaning | Error Code | Behavior
--- | --- | --- | ---
Success | Success | 0000 | The SCP has successfully stored the SOP Instance. If all SOP Instances in a send job have status success then the job is marked as complete.
Refused | Out of Resources | A700-A7FF | The Association is aborted using A-ABORT and the send job is marked as failed. The status meaning is logged and the job failure is reported to the user via the job control application. This is a transient failure.
Error | Data Set does not match SOP Class | A900-A9FF | The Association is aborted using A-ABORT and the send job is marked as failed. The status meaning is logged and the job failure is reported to the user via the job control application.
Error | Cannot Understand | C000-CFFF | The Association is aborted using A-ABORT and the send job is marked as failed. The status meaning is logged and the job failure is reported to the user via the job control application.
Warning | Coercion of Data Elements | B000 | Image transmission is considered successful but the status meaning is logged.
Warning | Data Set does not match SOP Class | B007 | Image transmission is considered successful but the status meaning is logged.
Warning | Elements Discarded | B006 | Image transmission is considered successful but the status meaning is logged.
* | * | Any other status code. | The Association is aborted using A-ABORT and the send job is marked as failed. The status code is logged and the job failure is reported to the user via the job control application.

The behavior of Storage AE during communication failure is summarized in the Table below:

Table B.4.2-9. Storage Communication Failure Behavior

Exception | Behavior
--- | ---
Timeout | The Association is aborted using A-ABORT and the send job is marked as failed. The reason is logged and the job failure is reported to the user via the job control application.
Association aborted by the SCP or network layers | The send job is marked as failed. The reason is logged and the job failure is reported to the user via the job control application.

A failed send job can be restarted by user interaction. The system can be configured to automatically resend failed jobs if a transient status code is received. The delay between resending failed jobs and the number of retries is also configurable.

The contents of X-Ray Radio Fluoroscopic Image Storage SOP Instances created by EXAMPLE-INTEGRATED-MODALITY conform to the DICOM X-Ray Radio Fluoroscopic Image IOD definition and are described in Section B.8.1.

The contents of Grayscale Softcopy Presentation State Storage SOP Instances created by EXAMPLE-INTEGRATED-MODALITY conform to the DICOM Grayscale Softcopy Presentation State IOD and are described in Section B.8.1.

Grayscale Softcopy Presentation State Storage SOP Instances are created upon user request (e.g., explicitly via "Save" or implicitly via "Close Patient") in order to save the most recent visual appearance of an image (e.g., window center/width, shutters, graphic annotations). When saving the visual appearance, a default Presentation Label will be supplied, which the user can change. The user also has the possibility to enter a detailed Presentation Description. If multiple images from the same study are being displayed the request to save the visual appearance will create one or more Presentation States referencing all displayed images. If images from multiple studies are being displayed at least a separate Presentation State will be created for each study.

When displaying an existing image the most recently saved Grayscale Softcopy Presentation State containing references to the image will be automatically applied. The user has the option to select other Presentation States that also reference the image.

Grayscale Softcopy Presentation State Storage SOP Instances created by EXAMPLE-INTEGRATED-MODALITY will only reference instances of X-Ray Radio Fluoroscopic Image Storage SOP Instances.

Graphical annotations and shutters are only stored in Grayscale Softcopy Presentation State objects. Remote AEs that do not support the Grayscale Softcopy Presentation State Storage SOP Class will not have access to graphical annotations or shutters created by EXAMPLE-INTEGRATED-MODALITY.

###### B.4.2.1.3.1.4 SOP Specific Conformance for Storage Commitment SOP Class

###### B.4.2.1.3.1.4.1 Storage Commitment Operations (N-ACTION)

The Storage AE will request storage commitment for instances of the X-Ray Radio Fluoroscopic Image Storage SOP Class and Grayscale Softcopy Presentation State Storage SOP Class if the Remote AE is configured as an archive device and a presentation context for the Storage Commitment Push Model has been accepted.

The Storage AE will consider Storage Commitment failed if no N-EVENT-REPORT is received for a Transaction UID within a configurable time period after receiving a successful N-ACTION response (duration of applicability for a Transaction UID).

The Storage AE does not send the optional Storage Media FileSet ID & UID Attributes or the Referenced Study Component Sequence Attribute in the N-ACTION

The behavior of Storage AE when encountering status codes in a N-ACTION response is summarized in the Table below:

Table B.4.2-10. Storage Commitment N-ACTION Response Status Handling Behavior

Service Status | Further Meaning | Error Code | Behavior
--- | --- | --- | ---
Success | Success | 0000 | The request for storage comment is considered successfully sent. A timer is started that will expire if no N-EVENT-REPORT for the Transaction UID is received within a configurable timeout period.
* | * | Any other status code. | The Association is aborted using A-ABORT and the request for storage comment is marked as failed. The status meaning is logged and reported to the user.

The behavior of Storage AE during communication failure is summarized in the Table below:

Table B.4.2-11. Storage Commitment Communication Failure Behavior

Exception | Behavior
--- | ---
Timeout | The Association is aborted using A-ABORT and the send job is marked as failed. The reason is logged and the job failure is reported to the user via the job control application.
Association aborted by the SCP or network layers | The send job is marked as failed. The reason is logged and the job failure is reported to the user via the job control application.

###### B.4.2.1.3.1.4.2 Storage Commitment Notifications (N-EVENT-REPORT)

The Storage AE is capable of receiving an N-EVENT-REPORT notification if it has successfully negotiated a Presentation Context for the Storage Commitment Push Model (i.e., only associations established with archive devices).

Upon receipt of a N-EVENT-REPORT the timer associated with the Transaction UID will be canceled.

The behavior of Storage AE when receiving Event Types within the N-EVENT-REPORT is summarized in the Table below.

Table B.4.2-12. Storage Commitment N-EVENT-REPORT Behavior

Event Type Name | Event Type ID | Behavior
--- | --- | ---
Storage Commitment Request Successful | 1 | The Referenced SOP Instances under Referenced SOP Sequence (0008,1199) are marked within the database as "Stored & Committed (SC) " to the value of Retrieve AE Title (0008,0054). Successfully committed SOP Instances are candidates for automatic deletion from the local database if local resources become scarce. The conditions under which automatic deletion is initiated and the amount of space freed are site configurable. SOP Instances will not be deleted if they are marked with a lock flag. The least recently accessed SOP Instances are deleted first.
Storage Commitment Request Complete - Failures Exist | 2 | The Referenced SOP Instances under Referenced SOP Sequence (0008,1199) are treated in the same way as in the success case (Event Type 1). The Referenced SOP Instances under Failed SOP Sequence (0008,1198) are marked within the database as "Store & Commit Failed (Sf) ". The Failure Reasons are logged and the job failure is reported to the user via the job control application. A send job that failed storage commitment will not be automatically restarted but can be restarted by user interaction.

The reasons for returning specific status codes in a N-EVENT-REPORT response are summarized in the Table below.

Table B.4.2-13. Storage Commitment N-EVENT-REPORT Response Status Reasons

Service Status | Further Meaning | Error Code | Reasons
--- | --- | --- | ---
Success | Success | 0000 | The storage commitment result has been successfully received.
Failure | Unrecognized Operation | 0211H | The Transaction UID in the N-EVENT-REPORT request is not recognized (was never issued within an N-ACTION request).
Failure | Resource Limitation | 0213H | The Transaction UID in the N-EVENT-REPORT request has expired (no N-EVENT-REPORT was received within a configurable time limit).
Failure | No Such Event Type | 0113H | An invalid Event Type ID was supplied in the N-EVENT-REPORT request.
Failure | Processing Failure | 0110H | An internal error occurred during processing of the N-EVENT-REPORT. A short description of the error will be returned in Error Comment (0000,0902).
Failure | Invalid Argument Value | 0115H | One or more SOP Instance UIDs with the Referenced SOP Sequence (0008,1199) or Failed SOP Sequence (0008,1198) was not included in the Storage Commitment Request associated with this Transaction UID. The unrecognized SOP Instance UIDs will be returned within the Event Information of the N-EVENT-REPORT response.

##### B.4.2.1.4 Association Acceptance Policy

###### B.4.2.1.4.1 Activity - Receive Storage Commitment Response

###### B.4.2.1.4.1.1 Description and Sequencing of Activities

The Storage AE will accept associations in order to receive responses to a Storage Commitment Request.

Figure B.4.2-2. Sequencing of Activity - Receive Storage Commitment Response

A possible sequence of interactions between the Storage AE and an Image Manager (e.g., a storage or archive device supporting Storage Commitment SOP Classes as an SCP) is illustrated in the Figure above:

1. The Image Manager opens a new association with the Storage AE.

2. The Image Manager sends an N-EVENT-REPORT request notifying the Storage AE of the status of a previous Storage Commitment Request. The Storage AE replies with a N-EVENT-REPORT response confirming receipt.

3. The Image Manager closes the association with the Storage AE.

The Storage AE may reject association attempts as shown in the Table below. The Result, Source and Reason/Diag columns represent the values returned in the appropriate fields of an ASSOCIATE-RJ PDU (see Section 9.3.4 in PS3.8 ). The contents of the Source column is abbreviated to save space and the meaning of the abbreviations are:

1. 1 - DICOM UL service-user

2. 2 - DICOM UL service-provider (ASCE related function)

3. 3 - DICOM UL service-provider (Presentation related function)

Table B.4.2-14. Association Rejection Reasons

Result | Source | Reason/Diag | Explanation
--- | --- | --- | ---
2 - rejected-transient | c | 2 - local-limit-exceeded | The (configurable) maximum number of simultaneous associations has been reached. An association request with the same parameters may succeed at a later time.
2 - rejected-transient | c | 1 - temporary-congestion | No associations can be accepted at this time due to the real-time requirements of higher priority activities (e.g., during image acquisition no associations will be accepted) or because insufficient resources are available (e.g., memory, processes, threads). An association request with the same parameters may succeed at a later time.
1 - rejected-permanent | a | 2 - application-context-name-not-supported | The association request contained an unsupported Application Context Name. An association request with the same parameters will not succeed at a later time.
1 - rejected-permanent | a | 7 - called-AE-title-not-recognized | The association request contained an unrecognized Called AE Title. An association request with the same parameters will not succeed at a later time unless configuration changes are made. This rejection reason normally occurs when the association initiator is incorrectly configured and attempts to address the association acceptor using the wrong AE Title.
1 - rejected-permanent | a | 3 - calling-AE-title-not-recognized | The association request contained an unrecognized Calling AE Title. An association request with the same parameters will not succeed at a later time unless configuration changes are made. This rejection reason normally occurs when the association acceptor has not been configured to recognize the AE Title of the association initiator.
1 - rejected-permanent | b | 1 - no-reason-given | The association request could not be parsed. An association request with the same format will not succeed at a later time.

###### B.4.2.1.4.1.2 Accepted Presentation Contexts

The Storage AE will accept Presentation Contexts as shown in the Table below.

Table B.4.2-15. Acceptable Presentation Contexts for Activity Receive Storage Commitment Response

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name List | UID List
Storage Commitment Push Model | 1.2.840.10008.1.20.1 | Implicit VR Little Endian Explicit VR Little Endian | 1.2.840.10008.1.2 1.2.840.10008.1.2.1 | SCU | None
Verification | 1.2.840.10008.1.1 | Implicit VR Little Endian Explicit VR Little Endian | 1.2.840.10008.1.2 1.2.840.10008.1.2.1 | SCP | None

The Storage AE will prefer to select the Explicit VR Little Endian Transfer Syntax if multiple transfer syntaxes are offered. The Storage AE will only accept the SCU role (which must be proposed via SCP/SCU Role Selection Negotiation) within a Presentation Context for the Storage Commitment Push Model SOP Class.

###### B.4.2.1.4.1.3 SOP Specific Conformance for Storage Commitment SOP Class

###### B.4.2.1.4.1.3.1 Storage Commitment Notifications (N-EVENT-REPORT)

Upon receipt of a N-EVENT-REPORT the timer associated with the Transaction UID will be canceled.

The behavior of Storage AE when receiving Event Types within the N-EVENT-REPORT is summarized in Table B.4.2-12.

The reasons for returning specific status codes in a N-EVENT-REPORT response are summarized in Table B.4.2-13.

###### B.4.2.1.4.1.4 SOP Specific Conformance for Verification SOP Class

The Storage AE provides standard conformance to the Verification SOP Class as an SCP. If the C-ECHO request was successfully received, a 0000 (Success) status code will be returned in the C-ECHO response. Otherwise, a C000 (Error - Cannot Understand) status code will be returned in the C-ECHO response.

Prev | Up | Next
B.4 Networking | Home | B.4.2.2 Workflow Application Entity Specification