[Bloat] Really getting 1G out of ISP?

Stephen Hemminger stephen at networkplumber.org
Tue Jun 29 15:48:31 EDT 2021


On Tue, 22 Jun 2021 22:51:18 +0000
"Livingood, Jason" <Jason_Livingood at comcast.com> wrote:

> > It doesn't help that all the local ISP's claim 10Mbit upload even with 1G download. Is this a head end provisioning problem or related to Docsis 3.0 (or later) modems?  
> 
> I'll cover this in an upcoming technical paper (mid-July I hope). Depending on the DOCSIS version, CMTS, and cable modems involved you may have no AQM, or buffer controls for the cable modem, or AQM (sort of) on the CMTS and in the cable modem. In the Comcast network you should find AQM in the upstream queue on the cable modems for which we have deployed RDK-B software (XB6 and XB7), while other devices would have buffer controls.
> 
> JL
> 

Just a short update. The cable modem matters. Updated from Docsis 3.0 modem with bad Intel Puma chipset
to new model with Docsis 3.1 and Broadcom and things are much more stable.

As far as AQM, in this setup; fq_codel does much better than the Cake configuration. With fq_codel can
see 700Mbit download speed. It looks like Cake is using more CPU especialy since the Cake configuration
is using an ifb ingress queue discipline as well.


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