pynetdicom.pdu_primitives.A_RELEASE

class pynetdicom.pdu_primitives.A_RELEASE[source][source]

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__()[source][source]

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

Methods

__init__() Initialize self.

Attributes

reason Return the Reason parameter.
result Return the Result parameter.
reason

Return the Reason parameter.

result

Return the Result parameter.