[Tsvwg] Re: HighSpeed TCP for Large Congestion Windows
Sally Floyd <floyd@icir.org> Tue, 30 July 2002 11:55 UTC
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To: Reiner Ludwig <Reiner.Ludwig@ericsson.com>
cc: tsvwg@ietf.org
From: Sally Floyd <floyd@icir.org>
Date: Mon, 29 Jul 2002 15:20:47 -0700
Subject: [Tsvwg] Re: HighSpeed TCP for Large Congestion Windows
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Reiner - >I have few comments about that draft ... > >1. I'm not convinced that this is a real problem for the (public) Internet: As I said in the viewgraphs, I certainly don't think this is a pressing problem in the Internet today, for anyone. The HighSpeed TCP draft tried to be clear about the problem description, which is the *very* small packet drop/mark rates needed to sustain very high congestion windows with current TCP. The reason to bring this to tsvwg is exactly to hear whether people feel this is inappropriate to bring to the IETF, or not. (My own reading of the sense of the working group meeting was that people felt that this *was* appropriate to bring to the IETF.) >- Applications that only send a few 10 Gigabytes every now and then won't >benefit from HighSpeed-TCP since the TCP sender will have to reset, or at >least decay its congestion window during the idle phases. Such applications >suffer most of all from the slow start. The Quick-Start draft tries to address this issue. >- In a regime of CWNDs on the order of 100.000 segments (probably even >sooner), why would a single packet loss per window be treated the same as a >loss of half a window worth of segments? This was always something that >bugged me about TCP-SACK. Actually, TCP-SACK doesn't respond the same to those two cases. It is true that it only halves its congestion window once for a round-trip time, regardless of the number of losses or marks in that window of data, as did Tahoe TCP before it in 1988, and as seems quite correct to me. But SACK TCP is ACK-clocked even during Fast Recovery, and does respond somewhat differently to one loss than to half a window of losses. draft-allman-tcp-sack-12.txt of course has the current-best-practice for SACK TCP. - Sally _______________________________________________ tsvwg mailing list tsvwg@ietf.org https://www1.ietf.org/mailman/listinfo/tsvwg
- [Tsvwg] Re: HighSpeed TCP for Large Congestion Wi… Sally Floyd
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Joe Touch
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Joe Touch
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Sally Floyd
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Reiner Ludwig
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Sally Floyd
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Joe Touch
- Fwd: Re: [Tsvwg] Re: HighSpeed TCP for Large Cong… Reiner Ludwig
- Fwd: Re: [Tsvwg] Re: HighSpeed TCP for Large Cong… Reiner Ludwig
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Reiner Ludwig
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Sally Floyd
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Marco Mellia
- RE: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Black_David
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Arun Prasad
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Joe Touch
- RE: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Black_David
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Joe Touch
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Sally Floyd
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Mark Allman
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Marco Mellia
- Re: [Tsvwg] Re: HighSpeed TCP for Large Congestio… Mark Allman