8 Protocol Overview

This Section provides an overview of the DIMSE protocol machine. The DIMSE protocol machine defines the procedures and the encoding rules necessary to construct Messages used to exchange command requests and responses between peer DIMSE Service Users (e.g., two DICOM Application Entities). The relationship between Messages and the different types of service primitives is shown in Figure 7-1.

The DIMSE protocol machine accepts DIMSE Service User request and response service primitives and constructs Messages defined by the procedures defined in 9.3 and 10.3. The DIMSE protocol machine accepts Messages and passes them to the DIMSE Service User by the means of indication and confirmation service primitives.

Procedures define the rules for the transfer of Messages that convey command requests and responses. These rules define interpretation of the various fields in the command part of the Message. They do not define what an Invoking DIMSE Service User should do with the information (the Data Set part of the Message) it requested nor how a Performing DIMSE Service User should process the operation.

Messages may be fragmented. The fragmentation of Messages exchanged between peer DICOM Application Entities and the P-DATA service used to exchange these Message fragments are defined in Annex F.

The Invoking DIMSE Service User Request primitive results in a Message carrying a Command Request (with an optional associated Data Set). Each Message induces an indication primitive to the Performing DIMSE Service User.

The Performing DIMSE Service User response primitives result in a Message carrying a Command Response (with an optional associated Data Set). Each Message induces a confirmation primitive to the Invoking DIMSE Service User.