Xerox 96MX - Manual (Page 437)

OFFLINE SPECIFICATIONS
XEROX DOCUPRINT 96/DOCUPRINT 96MX LPS PDL REFERENCE D-7
• 1 byte - Connection control (per the Sequenced Packet
Protocol)
• 1 byte - Data stream type (per the Sequenced Packet Protocol)
• 2 bytes - Length (per the Internet Datagram Protocol)
•
2 bytes - Source socket number (per the Internet Datagram
Protocol)
• 2 bytes - Destination socket number (per the Internet Datagram
Protocol)
•
4 bytes - Reserve for future use
Points to note
Version 0.1, (version 0 in the high-order byte; subversion 1, in the low
order byte) is the only version currently supported.
Currently, the end-of-message bit is defined for the connection
control field. It is set in the header of any logical block containing the
last byte of a data stream. Bit 3 (10 hexadecimal) is the assigned bit
for the End-of-Message flag, as defined by the Sequenced Packet
Protocol.
The four data stream type values assigned are as follows:
0 = Courier-encoded print message
1 = Bulk data, such as Interpress
2 = Courier-encoded routing data
254 = End
The data stream types and the connection control fields are planned
to be compatible with the Sequenced Packet Protocol.
The logical block must be an integral number of 16-bit words, while
the data contained in it is not so constrained, implying that there may
be a garbage byte at the end of the logical block. This garbage byte
is not included in the length field but is included in the checksum.
Instead of using addresses as defined in the Internet Datagram
Protocol, routing information (destination and source) is represented
by Courier-encoded clearinghouse three-part names, that is,
Name:Domain:Organization. The Courier encoding of a
clearinghouse name is a RECORD of three STRINGs. If the names
are unknown/nonexistent, they are represented by strings of zero (0)
length.
A file is defined as all the information between the start-of-file and
end-of-file label groups. If the tape format supports it, a file may span
volumes. A file fully contains one or more documents. (A document
may not span file boundaries.) Information is stored on a file in the
following order: 1 routing logical block 1 or more Courier-encoded
print procedure message logical blocks 0 or more bulk logical blocks
Optional repetitions of b- followed by c-type logical blocks An end
logical block.
The recipient may choose not to verify the checksum as the default.
However, some means must be provided for enabling checksum
verification if the sender specifically requests the service. The
presence of valid checksums (as opposed to the null value, all bits,
that is, FFFF hexadecimal) does not guarantee that checksums are
verified by the recipient.