Hi Toke,
> Gesendet: Freitag, 06. November 2020 um 17:17 Uhr
> Von: "Toke Høiland-Jørgensen via Bloat" <[email protected]>
> An: "Stephen Hemminger" <[email protected]>, "Toke Høiland-Jørgensen
> via Bloat" <[email protected]>
> Betreff: Re: [Bloat] Comparing bufferbloat tests (was: We built a new
> bufferbloat test and keen for feedback)
>
> Stephen Hemminger <[email protected]> writes:
>
> > PS: Why to US providers have such asymmetric bandwidth? Getting something
> > symmetric
> > requires going to a $$$ business rate.
>
> For Cable, the DOCSIS standard is asymmetric by design, but not *that*
> asymmetric.
Unfortunately is is that bad: DOCSIS 3.0 Downstream 108 MHz to 1002 MHz
Upstream 30 MHz to 85 MHz, so (1002-108)/(85-30) 16:1, but not all cable co,
have matching upstream filters for 85MHz. Then again, the two ACK per two full
segment rule puts a lower end in, with what an ISP can get away, if the
customer is expected to at least see the downstream rate in speedtests, I can
never remember whether that is essentially 20:1 or 40:1, but since then GRO?GSO
and friends, as well as ACK filtering has reduced the ACK traffic somewhat...
> I *think* the rest is because providers have to assign
> channels independently for upstream and downstream, and if they just
> assign them all to downstream they can advertise a bigger number...
They wished, once they deploy upstream amplifiers these have a fixed
frequency split and need to be replaced if the spilt is changed, that gets
expensive quickly... or so I have heard.
Best Regards
Sebastian
>
> -Toke
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