DDSIRTP2 — Clarify Data Encapsulation Schemes

Source:
Real-Time Innovations, Inc. (Ken Brophy, ken@rti.com)
Summary:
Data encapsulation for Serialized Data Fragments needs differentiation from data encapsulation of serialized data. Fragmentation should be done after encapsulation of large serialized data. Rather than having an encapsulation header for each fragment, only a single encapsulation header is needed, as this is used after the sample has been reconstituted from its fragments. The specification of data encapsulation schemes should describe this.

Also, in Sections 10.1.1-2, the length field of the data encapsulation schemes shown in the submessage diagrams are unnecessary, because the serialized data and fragments already contain sufficient information to determine the length of data. Instead, the field should be designated for data encapsulation scheme-specific options.
Resolution:
Replace the length field of the standard data encapsulation schemes with a scheme-specific option field.

Define fragmentation as happening after encapsulation of a large data sample.

Revised Text:
· Section 10.1.1.2
WAS
0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (CDR Big Endian) ~

------------------------------------------------------+

0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (CDR Little Endian) ~

------------------------------------------------------+

NOW:
0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (CDR Big Endian) ~

------------------------------------------------------+
Fragmentation is done after encapsulation of large serialized data.

0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (CDR Little Endian) ~

------------------------------------------------------+

· Section 10.1.1.3
WAS:
0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (ParameterList CDR Big Endian) ~

------------------------------------------------------+

0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (ParameterList CDR Little Endian) ~

------------------------------------------------------+

NOW:
0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (ParameterList CDR Big Endian) ~

------------------------------------------------------+

0...2...........8...............16..............24..............32
+

------------------------------------------------------+

~ Serialized Data (ParameterList CDR Little Endian) ~

------------------------------------------------------+

Fragmentation is done after encapsulation of large serialized data, so a SerializedDataFragment may contain the encapsulation header of its larger opaque SerializedData sample.

see above