DICOM PS3.8 2019b - Network Communication Support for Message Exchange

9.3.3.2 Presentation Context Item Structure

The Presentation Context Item shall be made of a sequence of mandatory fixed length fields followed by a variable field. Table 9-18 shows the sequence of the mandatory fields.

The variable field shall consist of one Transfer Syntax Sub-Item.

Table 9-18. Presentation Context Item Fields

Item bytes

Field name

Description of field

1

Item-type

21H

2

Reserved

This reserved field shall be sent with a value 00H but not tested to this value when received.

3-4

Item-length

This Item-length shall be the number of bytes from the first byte of the following field to the last byte of the Transfer Syntax Sub-Item. It shall be encoded as an unsigned binary number.

5

Presentation-context-ID

Presentation-context-ID values shall be odd integers between 1 and 255, encoded as an unsigned binary number. For a complete description of the use of this field see Section 7.1.1.13.

6

Reserved

This reserved field shall be sent with a value 00H but not tested to this value when received.

7

Result/Reason

This Result/Reason field shall contain an integer value encoded as an unsigned binary number. One of the following values shall be used:

0 - acceptance

1 - user-rejection

2 - no-reason (provider rejection)

3 - abstract-syntax-not-supported (provider rejection)

4 - transfer-syntaxes-not-supported (provider rejection)

8

Reserved

This reserved field shall be sent with a value 00H but not tested to this value when received.

9-xxx

Transfer syntax sub-item

This variable field shall contain one Transfer Syntax Sub-Item. When the Result/Reason field has a value other than acceptance (0), this field shall not be significant and its value shall not be tested when received. For a complete description of the use and encoding of this item see Section 9.3.3.2.1.


9.3.3.2.1 Transfer Syntax Sub-Item Structure

The Transfer Syntax Sub-Item shall be made of a sequence of mandatory fixed length fields followed by a variable field. Table 9-19 shows the sequence of the mandatory fields.

Table 9-19. Transfer Syntax Sub-Item Fields

Item bytes

Field name

Description of field

1

Item-type

40H

2

Reserved

This reserved field shall be sent with a value 00H but not tested to this value when received.

3-4

Item-length

This Item-length shall be the number of bytes from the first byte of the following field to the last byte of the Transfer-syntax-name field. It shall be encoded as an unsigned binary number.

5-xxx

Transfer-syntax-name

This variable field shall contain the Transfer-syntax-name proposed for this presentation context. A valid Transfer-syntax-name shall be encoded as defined in Annex F. For a description of the use of this field see Section 7.1.1.14. Transfer-syntax-names are structured as UIDs as defined in PS3.5 (see Annex B for an overview of this concept). DICOM Transfer-syntax-names are registered in PS3.5.


DICOM PS3.8 2019b - Network Communication Support for Message Exchange