[Bloat] [bbr-dev] Re: Are we heading towards a BBR-dominant Internet?

Bob McMahon bob.mcmahon at broadcom.com
Sat Aug 27 16:43:03 EDT 2022


Curious to what you're doing during development, if you can share?

Thanks,
Bob

On Sat, Aug 27, 2022 at 7:44 AM Neal Cardwell <ncardwell at google.com> wrote:

> Hi Bob,
>
> Good question. I can imagine a number of different techniques to generate
> and measure the traffic flows for this kind of study, and don't have any
> particular suggestions.
>
> neal
>
>
> On Fri, Aug 26, 2022 at 4:54 PM Bob McMahon <bob.mcmahon at broadcom.com>
> wrote:
>
>> Hi Neal,
>>
>> Any thoughts on tooling to generate and measure the traffic flows BBR is
>> designed to optimize? I've been adding some low duty cycle support in iperf
>> 2 <https://sourceforge.net/projects/iperf2/> with things like --bounceback
>> and --burst-period and --burst-period
>> <https://iperf2.sourceforge.io/iperf-manpage.html>. We could pull the
>> size and period from a known distribution or distributions though not sure
>> what to pick.
>>
>> Thanks,
>> Bob
>>
>> Bob
>>
>> On Fri, Aug 26, 2022 at 6:36 AM 'Neal Cardwell' via BBR Development <
>> bbr-dev at googlegroups.com> wrote:
>>
>>> Yes, I agree the assumptions are key here. One key aspect of this paper
>>> is that it focuses on the steady-state behavior of bulk flows.
>>>
>>> Once you allow for short flows (like web pages, RPCs, etc) to
>>> dynamically enter and leave a bottleneck, the considerations become
>>> different. As is well-known, Reno/CUBIC will starve themselves if new flows
>>> enter and cause loss too frequently. For CUBIC, for a somewhat typical 30ms
>>> broadband path with a flow fair share of 25 Mbit/sec, if new flows enter
>>> and cause loss more frequently than roughly every 2 seconds then CUBIC will
>>> not be able to utilize its fair share. For a high-speed WAN path, with
>>> 100ms RTT and fair share of 10 Gbit/sec,  if new flows enter and cause loss
>>> more frequently than roughly every 40 seconds then CUBIC will not be able
>>> to utilize its fair share. Basically, loss-based CC can starve itself in
>>> some very typical kinds of dynamic scenarios that happen in the real world.
>>>
>>> BBR is not trying to maintain a higher throughput than CUBIC in these
>>> kinds of scenarios with steady-state bulk flows. BBR is trying to be robust
>>> to the kinds of random packet loss that happen in the real world when there
>>> are flows dynamically entering/leaving a bottleneck.
>>>
>>> cheers,
>>> neal
>>>
>>>
>>>
>>>
>>> On Thu, Aug 25, 2022 at 8:01 PM Dave Taht via Bloat <
>>> bloat at lists.bufferbloat.net> wrote:
>>>
>>>> I rather enjoyed this one. I can't help but wonder what would happen
>>>> if we plugged some different assumptions into their model.
>>>>
>>>> https://www.comp.nus.edu.sg/~bleong/publications/imc2022-nash.pdf
>>>>
>>>> --
>>>> FQ World Domination pending:
>>>> https://blog.cerowrt.org/post/state_of_fq_codel/
>>>> Dave Täht CEO, TekLibre, LLC
>>>> _______________________________________________
>>>> Bloat mailing list
>>>> Bloat at lists.bufferbloat.net
>>>> https://lists.bufferbloat.net/listinfo/bloat
>>>>
>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "BBR Development" group.
>>> To unsubscribe from this group and stop receiving emails from it, send
>>> an email to bbr-dev+unsubscribe at googlegroups.com.
>>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/bbr-dev/CADVnQykKbnxpNcpuZATug_4VLhV1%3DaoTTQE2263o8HF9ye_TQg%40mail.gmail.com
>>> <https://groups.google.com/d/msgid/bbr-dev/CADVnQykKbnxpNcpuZATug_4VLhV1%3DaoTTQE2263o8HF9ye_TQg%40mail.gmail.com?utm_medium=email&utm_source=footer>
>>> .
>>>
>>
>> This electronic communication and the information and any files
>> transmitted with it, or attached to it, are confidential and are intended
>> solely for the use of the individual or entity to whom it is addressed and
>> may contain information that is confidential, legally privileged, protected
>> by privacy laws, or otherwise restricted from disclosure to anyone else. If
>> you are not the intended recipient or the person responsible for delivering
>> the e-mail to the intended recipient, you are hereby notified that any use,
>> copying, distributing, dissemination, forwarding, printing, or copying of
>> this e-mail is strictly prohibited. If you received this e-mail in error,
>> please return the e-mail to the sender, delete it from your computer, and
>> destroy any printed copy of it.
>
>

-- 
This electronic communication and the information and any files transmitted 
with it, or attached to it, are confidential and are intended solely for 
the use of the individual or entity to whom it is addressed and may contain 
information that is confidential, legally privileged, protected by privacy 
laws, or otherwise restricted from disclosure to anyone else. If you are 
not the intended recipient or the person responsible for delivering the 
e-mail to the intended recipient, you are hereby notified that any use, 
copying, distributing, dissemination, forwarding, printing, or copying of 
this e-mail is strictly prohibited. If you received this e-mail in error, 
please return the e-mail to the sender, delete it from your computer, and 
destroy any printed copy of it.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.bufferbloat.net/pipermail/bloat/attachments/20220827/de9b67f6/attachment.html>


More information about the Bloat mailing list