The information necessary for the C-ECHO request and indication DIMSE-C primitives are conveyed in the C-ECHO-RQ Message. The information necessary for the C-ECHO response and confirmation DIMSE-C primitives are conveyed in the C-ECHO-RSP Message.
The C-ECHO-RQ Message contains fields as defined in Table 9.3-12 Each field shall conform to DICOM encoding and Value Representation as defined in PS3.5. Fields are required as specified in the C-ECHO service definition unless otherwise noted in Table 9.3-12. Fields not specified in the C-ECHO service definition but present in Table 9.3-13 are required by the DIMSE-C protocol.
Table 9.3-12. C-ECHO-RQ Message Fields
|
Message Field
|
Tag
|
VR
|
VM
|
Description of Field
|
|
Command Group Length
|
(0000,0000)
|
UL
|
1
|
The even number of bytes from the end of the value field to the beginning of the next group.
|
|
Affected SOP Class UID
|
(0000,0002)
|
UI
|
1
|
SOP Class UID associated with this operation.
|
|
Command Field
|
(0000,0100)
|
US
|
1
|
This field distinguishes the DIMSE‑C operation conveyed by this Message. The value of this field shall be set to 0030H for the C-ECHO-RQ Message.
|
|
Message ID
|
(0000,0110)
|
US
|
1
|
Implementation-specific value that distinguishes this Message from other Messages.
|
|
Command Data Set Type
|
(0000,0800)
|
US
|
1
|
This field indicates that no Data Set is present in the Message and shall be set to a value of 0101H.
|