Re: Multiple Huffman code tables

I really don't know why you assume that they are optimized for a particular
brand.

2023年12月9日(土) 6:15 Rory Hewitt <rory.hewitt@gmail.com>:

> I have struggled with this conceptually when thinking about the QPACK
> static table.
>
> If a vast number of requests pass a 'branded' header, is it not in
> everyone's best interests to include that information, to reduce
> bytes-on-the-wire?
>
> That's why we should have a standard where 'common' headers have
> predefined positions in a static table, with separate versions of that
> table which can be used by the various vendors to append their own
> branded headers (or indeed, to have their own standalone static tables that
> include both their branded headers and also only the very small subset of
> the total set of possible headers that their devices may send or receive).
>
> For example, the various voice assistants (Google Assistant, Amazon Alexa,
> Apple Siri) only ever make requests to/from specified servers, so their
> designers are very well aware of the best way to encode the headers used in
> their transactions - both branded and not - to both reduce bytes
> on-the-wire AND limit the memory usage by those client devices storing
> QPACK/HPACK tables full of headers that they will never normally send or
> receive.
>
> On Fri, Dec 8, 2023 at 12:37 PM Christian Huitema <huitema@huitema.net>
> wrote:
>
>> I have no opinion on the benefits or not of defining better compression
>> than HPACK/QPACK, but I do have an opinion on the inclusion of brands in
>> the training set, like:
>>
>>
>>  > -1, '"Google Chrome";v="117", "Not;A=Brand";v="8", "Chromium";v="117"'
>>
>>  > -1, '"Google Chrome";v="117.0.5938.89", "Not;A=Brand";v="8.0.0.0",
>>  > "Chromium";v="117.0.5938.89"'
>>
>>  > -3, 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36
>>  > (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36'
>>
>>
>>  > 0, '1P_JAR=2023-11-22-18; expires=Fri, 22-Dec-2023 18:46:19 GMT;
>>  > path=/; domain=.google.com; Secure; SameSite=none'
>>
>> I assume that this kind of branded content reflects the reality of the
>> market place, and that assigning short Huffman codes to it will indeed
>> reduce the size of messages. But I think dedicating codes to such brands
>> today is an error. Market shares and product names will change over
>> time, making such optimizations ephemeral. But even if the optimizations
>> were stable, optimizing for the existing set of brands will provide an
>> advantage to these brands over newcomers, and thus contribute to
>> increased concentration -- something that standards should certainly not
>> encourage.
>>
>> -- Christian Huitema
>
>