[Bloat] Still seeing bloat with a DOCSIS 3.1 modem

[Toke Høiland-Jørgensen]

Sebastian Moeller <moeller0 at gmx.de> writes:

> Hi Toke,
>
>
>> On Mar 25, 2020, at 09:58, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
>> 
>> Aaron Wood <woody77 at gmail.com> writes:
>> 
>>> I recently upgraded service from 150up, 10dn Mbps to xfinity's gigabit
>>> (with 35Mbps up) tier, and picked up a DOCSIS 3.1 modem to go with it.
>>> 
>>> Flent test results are here:
>>> https://burntchrome.blogspot.com/2020/03/bufferbloat-with-comcast-gigabit-with.html
>>> 
>>> tl/dr;  1000ms of upstream bufferbloat
>>> 
>>> But it's DOCSIS 3.1, so why isn't PIE working?  Theory:  It's in DOCSIS 3.0
>>> upstream mode based on the status LEDs.  Hopefully it will go away if I can
>>> convince it to run in DOCSIS 3.1 mode.
>> 
>> I think that while PIE is "mandatory to implement" in DOCSIS 3.1, the
>> ISP still has to turn it on? So maybe yelling at them will work? (ha!)
>> 
>>> At the moment, however, my WRT1900AC isn't up to the task of dealing with
>>> these sorts of downstream rates.
>>> 
>>> So I'm looking at the apu2, which from this post:
>>> https://forum.openwrt.org/t/comparative-throughput-testing-including-nat-sqm-wireguard-and-openvpn/44724
>>> 
>>> Will certainly get most of the way there.
>> 
>> My Turris Omnia is doing fine on my 1Gbps connection (although that
>> hardly suffers from bloat, so I'm not doing any shaping; did try it
>> though, and it has no problem with running CAKE at 1Gbps).
>
> 	Well, doing local network flent RRUL stress tests indicated that
> 	my omnia (at that time with TOS4/Openwrt18) only allowed up to
> 	500/500 Mbps shaping with bi directionally saturating traffic
> 	with full MTU-sized packets. So I undirectional CAKE at 1Gbps
> 	can work, but under full load, I did not manage that, what did I
> 	wrong?

Hmm, not sure I've actually done full bidirectional shaping. And trying
it now, it does seem to be struggling...

-Toke