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dns-stats / draft-dns-capture-format

I-D for C-DNS file format
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Consider whether Class/Type is over-optimisation #10

Closed banburybill closed 7 years ago

banburybill commented 7 years ago

It feels like combining both class and type into ClassType might be over-optimization. Since Class will almost always be IN, why not just have this as its own object member?

banburybill commented 7 years ago

Putting them both into a table means that the reference from the Q/R item is a single byte value (since there are usually no more than 20 entries in that table).

Paul Hoffman spotted this (email, 2/11/16):

Arrrgh. I think I now understand that Class/Type tables (Section 7.10) are a way to say "there are a very limited number of combinations of Class and Types, so let's combine the two into single entries for pointing to". If I have that right, then making ClassType a list would save two bytes per entry in the table.

Defaulting class to IN still leaves type, most of the values of which are >=23 and so need 2 bytes to represent in CBOR.