Re: [Bloat] Comparing bufferbloat tests (was: We built a new bufferbloat test and keen for feedback)

[Sebastian Moeller <moeller0@gmx.de>]

Hi Toke,

> Gesendet: Freitag, 06. November 2020 um 17:17 Uhr
> Von: "Toke Høiland-Jørgensen via Bloat" <bloat@lists.bufferbloat.net>
> An: "Stephen Hemminger" <stephen@networkplumber.org>, "Toke Høiland-Jørgensen via Bloat" <bloat@lists.bufferbloat.net>
> Betreff: Re: [Bloat] Comparing bufferbloat tests (was: We built a new bufferbloat test and keen for feedback)
>
> Stephen Hemminger <stephen@networkplumber.org> 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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