Re: [aqm] [tcpm] TCP ACK Suppression
David Lang <david@lang.hm> Sat, 10 October 2015 05:58 UTC
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Date: Fri, 09 Oct 2015 22:58:34 -0700
From: David Lang <david@lang.hm>
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To: Joe Touch <touch@isi.edu>
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Cc: "LAUTENSCHLAEGER, Wolfram (Wolfram)" <wolfram.lautenschlaeger@alcatel-lucent.com>, Greg White <g.white@CableLabs.com>, "tcpm@ietf.org" <tcpm@ietf.org>, "aqm@ietf.org" <aqm@ietf.org>, "mallman@icir.org" <mallman@icir.org>
Subject: Re: [aqm] [tcpm] TCP ACK Suppression
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On Fri, 9 Oct 2015, Joe Touch wrote: > On 10/9/2015 7:14 PM, David Lang wrote: >> The problem with proposals like that is just like RFC3449 says, the >> source can't know what the network looks like to decide if there is a >> benefit to reducing ACKs. > > To understand your position, is your conclusion that if it benefits a > single place in the network, then that's enough of a view to know that > it's safe and beneficial throughout the network? No. But when something shows clear beneifts when deployed, clear problems need to be identified to counter those benefits, or alturnative methods of solveing the problem need to be shown. I didn't know about it initially (I was working from experience and logic), RFC3449 has explored many of the problems that cause and result from fewer than 1 ACK per 2 data packets, including worrying about the timing of the ACK packets. As much as you seem to want to make this discussion about cable modems and highly assymetric links, this discussiona ctually started from the position of packets in a particular flow being sent in bursts due to non-endpoint related reasons. It started with AQM queues, but radio networks (Wifi and Cell) have similar behavior (packets queue until a transmit window is available, tehn a bunch are sent at once) Cable modems were introduced to the discussion to counter the thought that sending fewer ACKs would destroy the Intenet. RFC3449 doesn't completely address the current situation, but it provides a very good place to start, and it seems to me that the solitions it explores to address the conerns that it (and you) raise are actually being addressed pretty completely. There are still some areas to talk about (ECN interaction for example) and we wshould be talking about those issues rather than arguing that the proposal violates holy writ. you want a network where packets are just forwarded with no modification and no delays. Unfortunantly such a network does not match the real world any longer (and it only approximated the real world in the first place) Shared media networks have existed since the earliest networking days. What is changing is theratio between the data speed when transmittingand the time available to transmit. Given the same number of stations in an area, I'll bet that old thinnet ethernet at 10Mb/s spent a significantly higher percentage of the time transmitting data than current Gb/s and immediate future 10Gb/s wireless networks. Just like wired network speeds are climbing with the MTU staying the ame, wireless network data rates are climbing but the time available for a given station is remaining the same (or shrinking), so the number of packets that get delayed until the next transmit slot are only going to keep climbing, no matter what anyone wants. The asymmetrical nature of the networks is just addng insult to injury, not the cause of the issues. Wireless networks are gaining the ability to transmit to multiple stations at once. But the nature of usage patterns and the physical geometry of the wired vs mobile ends of the link make the reality that only the wired end can effectively make use of this capability. this makes the availble downstream bandwidth on a network fabric grow much faster than the available upstream bandwidth. To some extent this will put less stress on the upstream side of the wired network it's attached to, but it will mean that the demand for mobile station transmit slots is only going to multiply. Just reducing the number of timeslots the base station uses isn't the answer because that will add latency to all the data downloads. IIRC, I saw a story today where one of the contenders for 5G cell networks is already at a ratio of 24:1 or worse. 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