Re: HTTP/2 and TCP CWND
Patrick McManus <mcmanus@ducksong.com> Wed, 17 April 2013 18:13 UTC
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Date: Wed, 17 Apr 2013 14:12:15 -0400
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From: Patrick McManus <mcmanus@ducksong.com>
To: Wesley Eddy <wes@mti-systems.com>
Cc: Eliot Lear <lear@cisco.com>, Gabriel Montenegro <Gabriel.Montenegro@microsoft.com>, Roberto Peon <grmocg@gmail.com>, "Simpson, Robby (GE Energy Management)" <robby.simpson@ge.com>, Robert Collins <robertc@squid-cache.org>, Jitu Padhye <padhye@microsoft.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>, "Brian Raymor (MS OPEN TECH)" <Brian.Raymor@microsoft.com>, Rob Trace <Rob.Trace@microsoft.com>, Dave Thaler <dthaler@microsoft.com>, Martin Thomson <martin.thomson@skype.net>, "Eggert, Lars" <lars@netapp.com>, Martin Stiemerling <martin.stiemerling@neclab.eu>
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Subject: Re: HTTP/2 and TCP CWND
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Hi Wes, On Wed, Apr 17, 2013 at 12:48 PM, Wesley Eddy <wes@mti-systems.com> wrote: > > It's definitely misinformation given the dynamic nature of the > CWND variable in TCP. This is not a path property like MTU that > can be thought of as relatively static, and it can change on short > timescales with high granularity. > Granted, an old CWND measurement can be inaccurate. It's an informed guess based on path performance. I'm sure we agree the path plays a (non-definitive) role in this. The alternative, IW, is an inaccurate guess too. Its an uninformed guess and I don't see why we should assume it would be more accurate. We can't argue that IW10 is strictly more conservative because my data says it typically isn't. (median SPDY CWND SETTING in firefox data is 30 x 1 session.. apples to apples that compares to at least 6 parallel HTTP/1 sessions of IW 10 each). Roberto suggested he's seen something similar. I'm not sure that more conservative is a better thing anyhow but I don't see how it applies in this case in any event. -Patrick
- HTTP/2 and TCP CWND Jitu Padhye
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Robert Collins
- Re: HTTP/2 and TCP CWND Patrick McManus
- Re: HTTP/2 and TCP CWND Roberto Peon
- RE: HTTP/2 and TCP CWND Gabriel Montenegro
- Re: HTTP/2 and TCP CWND Eliot Lear
- Re: HTTP/2 and TCP CWND Mark Nottingham
- Re: HTTP/2 and TCP CWND Simpson, Robby (GE Energy Management)
- Re: HTTP/2 and TCP CWND Roberto Peon
- RE: HTTP/2 and TCP CWND Gabriel Montenegro
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Patrick McManus
- Re: HTTP/2 and TCP CWND Martin Nilsson
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Eliot Lear
- Re: HTTP/2 and TCP CWND Simpson, Robby (GE Energy Management)
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Simpson, Robby (GE Energy Management)
- Re: HTTP/2 and TCP CWND Roberto Peon
- Re: HTTP/2 and TCP CWND Wesley Eddy
- Re: HTTP/2 and TCP CWND Patrick McManus
- Re: HTTP/2 and TCP CWND Yuchung Cheng
- Re: HTTP/2 and TCP CWND Eggert, Lars
- Re: HTTP/2 and TCP CWND Nandita Dukkipati
- Re: HTTP/2 and TCP CWND Wesley Eddy
- Re: HTTP/2 and TCP CWND Eliot Lear
- Re: HTTP/2 and TCP CWND Eggert, Lars
- Re: HTTP/2 and TCP CWND Eggert, Lars
- Re: HTTP/2 and TCP CWND Peter Lepeska
- Re: HTTP/2 and TCP CWND William Chan (陈智昌)
- Re: HTTP/2 and TCP CWND Peter Lepeska
- Re: HTTP/2 and TCP CWND William Chan (陈智昌)
- Re: HTTP/2 and TCP CWND Peter Lepeska
- Re: HTTP/2 and TCP CWND William Chan (陈智昌)
- Re: HTTP/2 and TCP CWND Peter Lepeska
- Re: HTTP/2 and TCP CWND William Chan (陈智昌)
- Re: HTTP/2 and TCP CWND Peter Lepeska
- Re: HTTP/2 and TCP CWND Mark Nottingham
- Re: HTTP/2 and TCP CWND Eliot Lear
- Re: HTTP/2 and TCP CWND Yuchung Cheng