Re: [aqm] TCP ACK Suppression
David Lang <david@lang.hm> Fri, 09 October 2015 18:46 UTC
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Date: Fri, 09 Oct 2015 11:45:54 -0700
From: David Lang <david@lang.hm>
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To: Yuchung Cheng <ycheng@google.com>
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Cc: "LAUTENSCHLAEGER, Wolfram (Wolfram)" <wolfram.lautenschlaeger@alcatel-lucent.com>, Christian Huitema <huitema@microsoft.com>, Joe Touch <touch@isi.edu>, "aqm@ietf.org" <aqm@ietf.org>, Greg White <g.white@cablelabs.com>
Subject: Re: [aqm] TCP ACK Suppression
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On Fri, 9 Oct 2015, Yuchung Cheng wrote: > Subject: Re: [aqm] TCP ACK Suppression > > On Thu, Oct 8, 2015 at 9:03 PM, David Lang <david@lang.hm> wrote: > >> On Fri, 9 Oct 2015, Christian Huitema wrote: >> >> On Thursday, October 8, 2015 5:43 PM, David Lang wrote: >>> >>>> ... >>>> For example, in the fq_codel/cake development, we're finding that there >>>> are >>>> some transports that bundle very large numbers of packets together to >>>> send >>>> at one time in order to maximize the transport bandwidth. (for example, >>>> 4x4 >>>> wifi sends a LOT of data in one transmit timeslot). Treating that large >>>> aggregate as a single packet seriously hurts fairness and latency on the >>>> next >>>> hop. So 'pulling apart' this aggregate into the individual >>>> packets/streams and >>>> making decisions based on the pieces ends up being a serious win in >>>> fairness >>>> and latency. >>>> >>> >>> Define "bundle" please. If they are making sure that several IP packets >>> are sent back to back in a single Wi-Fi slot, then it is of course >>> perfectly fine for AQM to handle the IP packets one by one. Does 4x4 Wi-Fi >>> do something else? >>> >> >> I don't remember the details from the discussion, but the combined bundle >> required extra steps to pull apart to get at the individual packets. IIRC, >> not doing so ended up with multi-MB chunks of data to be delivered, which >> blocked all other traffic while it was being delivered. >> >> Suggesting that the queues that build up produce a special enough case to >>>> consider thinning out the duplicate acks is a far cry from 'making a >>>> recommendation that breaks other recommendations' >>>> >>> >>> That definitely contradicts the TCP specs. So it is very much in "don't >>> go there" territory... >>> >> >> By 'not going there' you are crippling people's networks for the sake of >> following a spec. Rather than following the letter of the old spec, we >> should be looking at the reasons for it, and reasons to make exceptions. >> There is a long history of introducing new things that break the old way of >> doing things, from breaking "classful" network routing to Anycast, there >> are lots of things that "broke" the old way of doing things. >> >> In this case there is more than a decade of people doing exactly what >> shouldn't even be considered. >> >> I'll ask yet again, if acks have already been delayed so that they will be >> delivered at the same time as later acks, how much value do they actually >> provide? We need to compare whatever value this is against the cost of the >> misinformation that they provide, and the impact on other traffic. > > Does DOCSIS suppress/filter ACK with SACK blocks and/or ACKs with > timestamps? I don't know, but this discussion is not limited to DOCIS. also, see the other thread covering the RFC discussion. There's a lot more details there and in the RFC David Lang
- [aqm] TCP ACK Suppression Mikael Abrahamsson
- Re: [aqm] TCP ACK Suppression Greg White
- Re: [aqm] TCP ACK Suppression Mikael Abrahamsson
- Re: [aqm] TCP ACK Suppression LAUTENSCHLAEGER, Wolfram (Wolfram)
- Re: [aqm] TCP ACK Suppression Bless, Roland (TM)
- Re: [aqm] TCP ACK Suppression Mikael Abrahamsson
- Re: [aqm] TCP ACK Suppression Clark Gaylord
- Re: [aqm] TCP ACK Suppression Steve Bauer
- Re: [aqm] TCP ACK Suppression Francini, Andrea (Andrea)
- Re: [aqm] TCP ACK Suppression Richard Scheffenegger
- Re: [aqm] TCP ACK Suppression Greg White
- Re: [aqm] TCP ACK Suppression Bless, Roland (TM)
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Collier-Brown
- Re: [aqm] TCP ACK Suppression Jonathan Morton
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Richard Scheffenegger
- Re: [aqm] TCP ACK Suppression Yuchung Cheng
- Re: [aqm] TCP ACK Suppression Jonathan Morton
- Re: [aqm] TCP ACK Suppression Jonathan Morton
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Greg White
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Yuchung Cheng
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Christian Huitema
- Re: [aqm] TCP ACK Suppression Rick Jones
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Christian Huitema
- Re: [aqm] TCP ACK Suppression David Collier-Brown
- Re: [aqm] TCP ACK Suppression Simon Barber
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Yuchung Cheng
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression Greg White
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] TCP ACK Suppression Simon Barber
- Re: [aqm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Dave Taht
- Re: [aqm] [tcpm] TCP ACK Suppression Jonathan Morton
- Re: [aqm] [tcpm] TCP ACK Suppression Jonathan Morton
- Re: [aqm] [tcpm] TCP ACK Suppression Simon Barber
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Jonathan Morton
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Mikael Abrahamsson
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression Greg White
- Re: [aqm] [tcpm] TCP ACK Suppression Joe Touch
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang
- Re: [aqm] [tcpm] TCP ACK Suppression David Lang