pynetdicom.pdu_primitives.A_RELEASE

class pynetdicom.pdu_primitives.A_RELEASE

An A-RELEASE primitive.

The release of an association between two AEs shall be performed through ACSE A-RELEASE request, indication, response and confirmation primitives. The initiator of the service is called a Requestor and the service-user that receives the A-RELEASE indication is called the acceptor.

Service Procedure

  1. The user (Requestor) that desires to end the association issues an A-RELEASE request primitive. The Requestor shall not issue any other primitives other than A-ABORT until it receives an A-RELEASE confirmation primitive.

  2. The DUL provider issues an A-RELEASE indication to the Acceptor. The Acceptor shall not issue any other primitives other than A-RELEASE response, A-ABORT request or P-DATA request.

  3. To complete the release, the Acceptor replies using an A-RELEASE response primitive, with “affirmative” as the result parameter.

  4. After the Acceptor issues the A-RELEASE response it shall not issue any more primitives.

  5. The Requestor shall issue an A-RELEASE confirmation primitive always with an “affirmative” value for the Result parameter.

  6. A user may disrupt the release by issuing an A-ABORT request.

  7. A collision may occur when both users issue A-RELEASE requests simultaneously. In this situation both users receive an unexpect A-RELEASE indication primitive (instead of an A-RELEASE acceptance):

    1. The association requestor issues an A-RELEASE response primitive

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

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

    When both ACSE users have received an A-RELEASE confirmation primitive the association shall be released.

Parameter

Request

Indication

Response

Confirmation

reason

UF

UF(=)

UF

UF(=)

user info

NU

NU(=)

NU

NU(=)

result

MF

MF(=)

U - User option
UF - User option, fixed value
C - Conditional (on user option)
M - Mandatory
MF - Mandatory, fixed value
NU - Not used
(=) - shall have same value as request or response
reason

Fixed value of “normal”. Identifies the general level of urgency of the request.

Type

str

result

Must be None for request and indication, “affirmative” for response and confirmation.

Type

str or None

References

  • DICOM Standard, Part 8, Section 7.2

__init__()

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__()

Initialize self.

Attributes

reason

Return the Reason parameter.

result

Return the Result parameter.

property reason

Return the Reason parameter.

property result

Return the Result parameter.