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SAE J2735-Draft-Rev18 [issued: 06-26-07]
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This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
at that time to initiate another session. Note that other sessions, using other sessionIDs may be occurring
during the same time. Management of sessionIDs is outside the scope of this message set.
The CRC value SHALL be computed by setting an initial CRC value of zero, and then computing the final
value by processing the message a single byte at a time and with each element taken in order starting from
the msgType up to and including all of the payload to determine the final value. The polynomial value and
algorithm used SHALL be the CRC-CCITT.
ASN.1 Representation:
GenericTransferMsg ::= SEQUENCE {
msgID DSRCmsgID, -- App ID value, 1 byte
sessionID INTEGER (0..255),
applicationID INTEGER (0..65535),
blockID INTEGER (0..65535), -- the block number which this is
blockCount INTEGER (0..65535), -- the number of blocks in total
wordCount INTEGER (0..65535), -- the number of bytes in this payload
payLoad PayloadData, -- the payload data to be transferred
crc INTEGER (0..65535), -- a CRC, if not provided by the framing
...
}
XML Representation:
<xs:element name="genericTransferMsg" type="GenericTransferMsg"/>
<xs:complexType name="GenericTransferMsg" >
<xs:sequence>
<xs:element name="msgID" type="DSRCmsgID" />
<!-- App ID value, 1 byte -->
<xs:element name="sessionID" >
<xs:simpleType>
<xs:restriction base="xs:unsignedByte"/>
</xs:simpleType>
</xs:element>
<xs:element name="applicationID" >
<xs:simpleType>
<xs:restriction base="xs:unsignedShort"/>
</xs:simpleType>
</xs:element>
<xs:element name="blockID" >
<xs:simpleType>
<xs:restriction base="xs:unsignedShort"/>
</xs:simpleType>
</xs:element>
<!-- the block number which this is -->
<xs:element name="blockCount" >
<xs:simpleType>
<xs:restriction base="xs:unsignedShort"/>
</xs:simpleType>
</xs:element>
<!-- the number of blocks in total -->
<xs:element name="wordCount" >
<xs:simpleType>
<xs:restriction base="xs:unsignedShort"/>
</xs:simpleType>
</xs:element>
<!-- the number of bytes in this payload -->
<xs:element name="payLoad" type="PayloadData" />
<!-- the payload data to be transferred -->
<xs:element name="crc" >
<xs:simpleType>
<xs:restriction base="xs:unsignedShort"/>
</xs:simpleType>
</xs:element>
<!-- a CRC, if not provided by the framing -->
</xs:sequence>
</xs:complexType>
Remarks: This message allows for transfer of up to 4,295 Megs of data to be sent per session per
application using a simplistic method without error recovery, but with basic error detection. It is intended