[External] Re: 10g residential CPE

Fri Dec 25 21:47:35 UTC 2020

fre. 25. dec. 2020 21.49 skrev Michael Thomas <mike at mtcc.com>:

>
> On 12/25/20 12:40 PM, Chris Adams wrote:
> >
> > The other aspect of it is that we're doing these downloads while
> > continuing to play other games and chat (both things sensitive to
> > latency).  Some have family/roommates in the home, so they may be
> > streaming audio and/or video at the same time.  Do we fill up a gigabit?
> > No, probably not... but we'd notice if we had a lot less.
>
> But using the right queuing disciplines it a lot cheaper than the brute
> force and ignorance of just upping the bandwidth, right?
>
> It seems really surprising after almost a decade of discovery of
> bufferbloat that most CPE are still doing tail drops.
>
> Mike
>

For download that queue discipline needs to be implemented at the ISP end.
It is just a week or so since I asked what other operators were doing with
that and I got very few replies. So maybe we can assume the answer is not
much.

I also learned that the big iron providers J and C only implements tail
drop and WRED. That's it. It is not sufficient to provide good service, so
the only option is to throw more bandwidth at the problem.

If the operator wants to keep bufferbloat low you will not be able to
utilise your 1 Gbps to that speed when downloading from distant servers.
But with the same bufferbloat measured in milliseconds you will still have
a 10x bigger buffer and thus 10x bigger bandwidth delay product. That
translates to 10x the speed. That speed might just be 100 Mbps on your 1000
Mbps connection. But it would have been just 10 Mbps on a 100 Mbps...

Regards

Baldur

>
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