7.3 A-ABORT Service
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## 7.3 A-ABORT Service

The ACSE A-ABORT service shall be used by a requestor in either of the AEs to cause the abnormal release of the association. It shall be a non-confirmed service. However, because of the possibility of an A-ABORT service procedure collision, the delivery of the indication primitive is not guaranteed. Should such a collision occur, both AEs are aware that the association has been terminated. The abort shall be performed through A-ABORT request and A-ABORT indication primitives.

### Note

An A-ABORT request primitive used on an established association may result in the destruction of data in transit.

Figure 7-3 illustrates aborting an established association between two AE's.

Figure 7-3. Association User Initiated Abort

### 7.3.1 A-ABORT Parameters

Table 7-5 lists the parameters for the A-ABORT service. Only the first parameter shall be used by DICOM Application Entities in this standard.

Table 7-5. A-ABORT Service Parameters

A-ABORT Parameter Name | Request | Indication
--- | --- | ---
abort source |  | M
user information | NU | NU(=)

#### 7.3.1.1 Abort Source

This parameter indicates the initiating source of this abort. It shall take one of the following symbolic values:

1. UL service-user

2. UL service-provider (ACSE related)

### 7.3.2 A-ABORT Service Procedure

7.3.2.1 When the A-ABORT service is used, the association shall be released abnormally and simultaneous with the abnormal release of the underlying connection.

7.3.2.2 A UL service-user that desires to release the association abnormally shall issue the A-ABORT request primitive. This requestor shall not issue any further primitives for the association.

7.3.2.3 The UL service-provider shall issue an A-ABORT indication primitive to the acceptor. The UL service-provider shall assign the value of "UL service-user" for the Abort Source parameter. The association and the underlying connection have been released.

7.3.2.4 The UL service-provider (ACSE related functions) may itself cause the abnormal release of the association because of internal errors. In this case, the UL service-provider shall issue A-ABORT indication primitives to acceptors in both AEs. The UL service-provider shall assign the value of "UL service-provider" to the Abort Source parameter. The user information parameter shall not be used.

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