DICOM PS3.8 2024e - Network Communication Support for Message Exchange

7.2.2 A-RELEASE Service Procedure

An UL service-user that desires to release the association shall issue an A-RELEASE request primitive. This requestor shall not issue any further primitives other than an A-ABORT request primitive until it receives an A-RELEASE confirmation primitive.

Note

Even though the requestor of the A-RELEASE service shall not issue any further primitive other than A-ABORT, it may receive P-DATA Indication primitives.

The UL service-provider shall issue an A-RELEASE indication primitive to the acceptor. The acceptor then shall not issue any UL primitives other than an A-RELEASE response primitive, an A-ABORT request primitive, or P-DATA Request primitive.

To complete the A-RELEASE service, the acceptor shall reply to the A-RELEASE indication primitive by issuing an A-RELEASE response primitive. An accepting DICOM Application Entity shall always issue an A-RELEASE response primitive with an "affirmative" result parameter (i.e., accept the release).

After an A-RELEASE response has been issued, the acceptor shall not issue any further primitives for the association thereafter, including P-DATA Requests.

The UL service-provider shall issue an A-RELEASE confirmation primitive always with an "affirmative" value for the Result parameter.

A requestor in either AE may disrupt the A-RELEASE service procedure by issuing an A-ABORT request. When the acceptor receives an A-ABORT indication, the association is released with the possible loss of information in transit.

An A-RELEASE service procedure collision results when requestors in both AEs simultaneously issue an A-RELEASE service primitive. In this situation, both UL service-users receive an unexpected A-RELEASE indication primitive. The following sequence shall occur to complete the normal release of the association:

  1. The association-requestor shall issue an A-RELEASE response primitive.

  2. The association-acceptor waits for an A-RELEASE confirmation primitive from its peer. When it receives one, it shall then issue an A-RELEASE response primitive.

  3. The association-requestor receives an A-RELEASE confirmation primitive.

The association shall be released when both ACSE service-users have received an A-RELEASE confirmation primitive.

DICOM PS3.8 2024e - Network Communication Support for Message Exchange