[Cerowrt-devel] DOCSIS 3+ recommendation?

Sebastian Moeller moeller0 at gmx.de
Wed Mar 18 04:06:12 EDT 2015

Hi David,

On March 18, 2015 5:34:30 AM GMT+01:00, "David P. Reed" <dpreed at reed.com> wrote:
>It is not the cable modem itself that is bufferbloated. It is the head
>end working with the cable modem. Docsis 3 has mechanisms to avoid
>queue buildup but they are turned on by the head end.

        I seem to recall that even on egress charter cable showed multiples hundred of bufferbloat, so I would argue that even at docs is 3.0 the modems might be over buffered or under-AQM'd. The head end certainly is another problem...

>I don't know for sure but I believe that the modem itself cannot
>measure or control the queueing in the system to minimize latency.

        I believe this is supposed to happen with docs is 3.1 where PIE is mandatory in the modems. Now whether the ISPs will activate it or not I do not know.

Best Regards

>You can use codel or whatever if you bound you traffic upward and
>stifle traffic downward. But that doesn't deal with the queueing in the
>link away from your home.
>On Mar 17, 2015, Valdis.Kletnieks at vt.edu wrote:
>>On Mon, 16 Mar 2015 13:35:32 -0700, Matt Taggart said:
>>> Hi cerowrt-devel,
>>> My cable internet provider (Comcast) has been pestering me (monthly
>>> and robocalls) to upgrade my cable modem to something newer. But I
>>> my current one (no wifi, battery backup) and it's been very stable
>>and can
>>> handle the data rates I am paying for. But they are starting to roll
>>> faster service plans and I guess it would be good to have that
>>> eventually they will probably boost the speed of the plan I'm paying
>>> So...
>>> Any recommendations for cable modems that are known to be solid and
>>> bufferbloated?
>>I've been using the Motorola Surfboard SB6141 on Comcast with good
>>Anybody got a good suggestion on how to test a cablemodem for
>>or what you can do about it anyhow (given that firmware is usually
>>from the ISP side)?
>>Cerowrt-devel mailing list
>>Cerowrt-devel at lists.bufferbloat.net
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