Loading...

XML

Word

Printable

Proposal:

Hide

Use the short topic name Topic Type to indicate a 1 byte Topic length instead of 2.

This would mean the two char topic names would need one byte more but topic names of every other length would need one byte fewere.

Show
Use the short topic name Topic Type to indicate a 1 byte Topic length instead of 2. This would mean the two char topic names would need one byte more but topic names of every other length would need one byte fewere.

Allowing two byte topic names made sense in MQTT-SN 1.2 because the Topic Alias field was two bytes so it could contain the topic name itself.

Now we have the option of long topic names this seems less coherent and raises questions:

one char topic names take up more space than 2 char
we have to define the syntax of two byte topic names specifically (a complication)
the sender has the option to send two char topic names in two ways, as a long topic name with length 2 or a 2 chars encoded in the Topic Alias field (again, needing clarification)