DCM's diagnostic services dispatcher (DSD) a Detailed

About
DSD sub-module responsible for checking incoming diagnostic validity of the request (diagnostic session / security access level / verification application permissions), and track the progress of execution of service requests.
[SWS_Dcm_00178] D DSD processing sub-module is only valid requests, and rejects invalid request. ⌋ ()
with Example
The following use cases are related, and are described in detail below:
 receives the request message and transmits a positive response message
 receives the request message and prohibits a positive response
 receives the request message and prohibits negative response
 receives the request message and sends negative response message
 sends a positive response message without a corresponding request
 segment response
receives the request message and transmits a positive response message to
the standard normal communication ( "ping-pong") this is the use case. Server receives the diagnosis request message. DSD submodule can ensure the validity of the request message. In such a case, the request is valid, the response is affirmative. The request will be forwarded to DSP sub-module corresponding data processor. When the data processor completes all data processing operations, it will trigger sub-module to transmit a response message DSD. If the data processor for processing service as part of the request immediately if indicator, the data processor may trigger the transmission inside the indication ( "sync"). If the processing takes a long time (e.g., the driver waits EEPROM), then the data processor to delay certain processing ( "asynchronous"). DSL submodule covers pending response mechanism. The data processor may transmit an explicit trigger, but may be triggered from the context of a data processor. After receiving the request message, corresponding DcmPduId will be blocked
by the DSL sub-module (see SWS_Dcm_00241). During the request process, until it is received before the corresponding response message and releases DcmPduId again, other requests can not receive the same type of protocol (e.g., session may be terminated by an enhanced session OBD).
Receiving a request message and to inhibit the affirmative response
which is before a sub use case.
UDS in the protocol, by setting a special bit in the request message to suppress the positive response (see SWS_Dcm_00200). This particular process is performed entirely suppressed in the DSD submodule.