
DCN Next Generation Open Interface Release 2.4 General
en | 17
Bosch Communications Systems | 2007 February | SRS_INF | Du010933
dwErrorPosition The byte offset in the message stream, where the fault is
detected.
Related messages:
Any message received by the DCN NG System and is not conform the message guideline as
described in 3.3.
3.3.3 Format of type MESSAGETYPE_OIP_Dcn
Command messages can be sent to control the DCN NG System. Commands always result
in a response from the DCN NG System. The expected response is referenced with each
command or the generic response MESSAGETYPE_OIP_ResponseProtocolError is
returned in case the message is corrupted. Each command message starts with a fixed
number of fields, which are presented below in structure format.
NOTE:
In the time between the transmission of the command message and the reception of the
response message, the DCN NG System can receive notification messages.
struct {
BYTE byMessageTypeHeader; /* Fixed value 0x43 */
WORD wFnId;
BYTE byDcnMsgType;
} OIP_DCN_MSGTYPE
struct {
OIP_DCN_MSGTYPE tMessageType;
DWORD dwLength;
DWORD dwReserved1;
DWORD dwReserved2;
BYTE byData[];
} OIP_Dcn;
Where:
byMessageTypeHeader Message type header byte with a fixed value of 0x43.
wFnId The function identifier.
byDcnMsgType Is equal to the byType value described in 3.2. Currently the
following types are defined for communication with the NCO:
• MDSM_REMOTEPROCEDURE_REQ
• MDSM_REMOTEPROCEDURE_RSP
• MDSM_NOTIFY
dwLength The total length of the command structure.
dwReserved1 Session sequence number. Currently the reserved1 is not
used and should be set to the value zero (0)
dwReserved2 Message sequence number. Currently the reserved2 is not
used and should be set to the value zero (0).
byData Data corresponding to the description of the message-type.
The data represents a structure which format is explained
hereafter together with the message-type.
3.3.4 Buffer overflow
Purpose:
Messages ready for transmission from the DCN NG System are queued. In case the
receive speed of the connected system is too low, the queue may overflow (dependant
on the number of generated events, resource update, etc.). Since the queue consumes
internal DCN NG System resources, overflow detection is present, which disconnects the
communication interface when the queue overflows its limit.
This may result in a loss of received events.
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