[Starlink] Of interest: Comcast AQM Paper

[Starlink] Of interest: Comcast AQM Paper

[Livingood, Jason]

 FYI that I will be presenting a lightning talk at the IRTF MAPRG meeting today at 17:30 ET (https://datatracker.ietf.org/meeting/111/materials/agenda-111-maprg). The talk links to a just-published paper at https://arxiv.org/abs/2107.13968 (click PDF link in upper right of page) that will likely be of interest to these two lists.

High-level: turning on AQM in the cable modem (upstream queue) took working latency from around 250 ms to between 15-30 ms, which is actually kind of cool. ;-) AQM is turned on in all of our CMTSes (downstream queue) and in DOCSIS 3.1 modems (upstream queue).

Have a nice weekend,
Jason

Re: [Starlink] [Bloat] Of interest: Comcast AQM Paper

[Simon Barber]

Awesome to hear that you are turning this on both upstream and downstream. Do you know if the wifi stacks in your home routers also have AQM?

Simon


> On Jul 30, 2021, at 10:28 PM, Livingood, Jason via Bloat <bloat@lists.bufferbloat.net> wrote:
> 
> FYI that I will be presenting a lightning talk at the IRTF MAPRG meeting today at 17:30 ET (https://datatracker.ietf.org/meeting/111/materials/agenda-111-maprg). The talk links to a just-published paper at https://arxiv.org/abs/2107.13968 (click PDF link in upper right of page) that will likely be of interest to these two lists.
> 
> High-level: turning on AQM in the cable modem (upstream queue) took working latency from around 250 ms to between 15-30 ms, which is actually kind of cool. ;-) AQM is turned on in all of our CMTSes (downstream queue) and in DOCSIS 3.1 modems (upstream queue).
> 
> Have a nice weekend,
> Jason
> 
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat

Re: [Starlink] [Bloat] Of interest: Comcast AQM Paper

[Aaron Wood]

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If we see that AQM appears to be not functioning as expected for upstream
connections on DOCSIS3.1, what's the right avenue for getting that
resolved?  (and does that only apply to the Comcast-owned, vs.
customer-owned, modems?)

On Sat, Jul 31, 2021 at 10:50 AM Simon Barber <simon@superduper.net> wrote:

> Awesome to hear that you are turning this on both upstream and downstream.
> Do you know if the wifi stacks in your home routers also have AQM?
>
> Simon
>
>
> > On Jul 30, 2021, at 10:28 PM, Livingood, Jason via Bloat <
> bloat@lists.bufferbloat.net> wrote:
> >
> > FYI that I will be presenting a lightning talk at the IRTF MAPRG meeting
> today at 17:30 ET (
> https://datatracker.ietf.org/meeting/111/materials/agenda-111-maprg). The
> talk links to a just-published paper at https://arxiv.org/abs/2107.13968
> (click PDF link in upper right of page) that will likely be of interest to
> these two lists.
> >
> > High-level: turning on AQM in the cable modem (upstream queue) took
> working latency from around 250 ms to between 15-30 ms, which is actually
> kind of cool. ;-) AQM is turned on in all of our CMTSes (downstream queue)
> and in DOCSIS 3.1 modems (upstream queue).
> >
> > Have a nice weekend,
> > Jason
> >
> > _______________________________________________
> > Bloat mailing list
> > Bloat@lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/bloat
>
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat
>

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Re: [Starlink] [Bloat] Of interest: Comcast AQM Paper

[Neal Cardwell]

On Sat, Jul 31, 2021 at 3:27 PM Aaron Wood <woody77@gmail.com> wrote:
>
> If we see that AQM appears to be not functioning as expected
>  for upstream connections on DOCSIS3.1, what's the right avenue
> for getting that resolved?  (and does that only apply to the
> Comcast-owned, vs. customer-owned, modems?)

FWIW, from the paper it sounds like not all Comcast cable modems
had/have PIE, which enabled the A/B experiment:

"10. Latency Measurement Results
As explained earlier, for two variants of XB6 cable modem gateway,
upstream DOCSIS-PIE AQM was enabled on the CGM4140COM (experiment)
variant but was not available on the TG3482G (control) variant during
the measurement period. The TG3482G variant used a buffer control
configuration that predated AQM in DOCSIS."

neal

>
> On Sat, Jul 31, 2021 at 10:50 AM Simon Barber <simon@superduper.net> wrote:
>>
>> Awesome to hear that you are turning this on both upstream and downstream. Do you know if the wifi stacks in your home routers also have AQM?
>>
>> Simon
>>
>>
>> > On Jul 30, 2021, at 10:28 PM, Livingood, Jason via Bloat <bloat@lists.bufferbloat.net> wrote:
>> >
>> > FYI that I will be presenting a lightning talk at the IRTF MAPRG meeting today at 17:30 ET (https://datatracker.ietf.org/meeting/111/materials/agenda-111-maprg). The talk links to a just-published paper at https://arxiv.org/abs/2107.13968 (click PDF link in upper right of page) that will likely be of interest to these two lists.
>> >
>> > High-level: turning on AQM in the cable modem (upstream queue) took working latency from around 250 ms to between 15-30 ms, which is actually kind of cool. ;-) AQM is turned on in all of our CMTSes (downstream queue) and in DOCSIS 3.1 modems (upstream queue).
>> >
>> > Have a nice weekend,
>> > Jason
>> >
>> > _______________________________________________
>> > Bloat mailing list
>> > Bloat@lists.bufferbloat.net
>> > https://lists.bufferbloat.net/listinfo/bloat
>>
>> _______________________________________________
>> Bloat mailing list
>> Bloat@lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/bloat
>
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat

Re: [Starlink] [Bloat] Of interest: Comcast AQM Paper

[Michael Richardson]

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Neal Cardwell via Bloat <bloat@lists.bufferbloat.net> wrote:
    > On Sat, Jul 31, 2021 at 3:27 PM Aaron Wood <woody77@gmail.com> wrote:
    >>
    >> If we see that AQM appears to be not functioning as expected
    >> for upstream connections on DOCSIS3.1, what's the right avenue
    >> for getting that resolved?  (and does that only apply to the
    >> Comcast-owned, vs. customer-owned, modems?)

    > FWIW, from the paper it sounds like not all Comcast cable modems
    > had/have PIE, which enabled the A/B experiment:

This does bring up an interesting discovery question:

the presences of AQM (whether PIE or FQ_CODEL), and what the settings might
be (for some things need to be tuned), would be something that might be
interested to emit via LLDP.
And/or at a /.well-known URL (accessible via IPv6-LL only).

--
Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide





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