DDS11 — (R#144) Default value for DataWriter RELIABILITY QoS

The specification states that the default value of the RELIABILITY QoS policy on a DataWriter is BEST_EFFORT; however this makes it automatically incompatible with readers that request a RELIABLE value. This situation is not a problem per se, but it means that applications desiring RELIABLE communications must change the default configuration in two places: both with the reader and with the writer.

Proposed Resolution:

Changing the default value-on the DataWriter only-to RELIABLE would make the initial configuration of DDS applications simpler. The default behavior would still be the same because the DataReader would still default to BEST_EFFORT and therefore the default communication would be BEST_EFFORT. However, applications desiring a RELIABLE setting would have to change the defaults in only one place: with the DataReader.

Proposed Revised Text:

Append the following sentence to the "Meaning" column of the RELIABILITY RELIABLE row of the table in 2.1.3: "This is the default value for DataWriters."

The final sentence in the "Meaning" column of the RELIABILITY BEST_EFFORT row of the table in 2.1.3 currently states: "This is the default value." This sentence should be amended: "This is the default value for DataReaders and Topics."

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