> Tony Finch <mailto:[email protected]>
> Friday, January 23, 2015 10:35 AM
>
> Paul Vixie <[email protected]> wrote:
>
> > why aren't we preferring a TCP/80 (and perhaps TCP/443) solution
>
> Inefficient encoding
> -> wastes battery
> -> greater serialization latency

i see your point about battery, and i hadn't considered that the common
configuration today and for the foreseeable future is mobile devices. i
don't know if that's a compelling argument, but it is an argument.

i don't think there's any real time (measurable) difference in
serialization (and deserialization) latency. it's been a long time since
processors were faster at accessing random memory locations using
offsets (in the sense of C structure variables) than they were at
accessing memory in order using auto-incrementing pointers. that's why
BIND8's "dns_parsemsg()" steps through the message in order, just as a
JSON parser would have to do.
>
> In-order responses
> -> head-of-line blocking
i expected that DNS-over-HTTP would work the same as WWW-over-HTTP,
which is to open multiple parallel TCP/80 (or TCP/443) sessions if
parallelism is required. either TCP sessions are cheap enough that this
doesn't matter, or, TCP sessions are expensive enough that we can't
leave them open for long (many seconds) periods of time.

-- 
Paul Vixie
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