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Re: Raise initial congestion window size / speedup slow start?

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From: Bill Davidsen
Subject: Re: Raise initial congestion window size / speedup slow start?
Date: Thursday, July 15, 2010 - 4:14 pm

David Miller wrote:
I think transit time measured in 1/10th sec would disqualify this as a "normal 
setup."

High bandwidth and high latency don't work well because you get "send until the 
window is full then wait for ack" and poor performance. I saw this with sat feed 
to Wyoming from GE's Research Center in upstate NY in the late 80's or early 
90's. (I think this was NYserNet at that time). I did feeds from NYC area to 
California and Hawaii with SBC in the early to mid 2k years. In every case 
SunOS, Solaris, AIX and Linux all failed to hit anything like reasonable 
transfer speeds without manually tweaking, and I got the advice on increasing 
window size from network engineers at ISPs and backbone providers.

The O.P. may have other issues, and may benefit from doing other things as well, 
but raising window size is a reasonable thing to do on links with RTT in 
hundreds of ms, and it's easy to try without changing config files.

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot
--
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Messages in current thread:
Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 3:43 am)
Re: Raise initial congestion window size / speedup slow start?, Alan Cox, (Wed Jul 14, 4:58 am)
Re: Raise initial congestion window size / speedup slow start?, Bill Davidsen, (Wed Jul 14, 8:21 am)
Re: Raise initial congestion window size / speedup slow start?, David Miller, (Wed Jul 14, 11:15 am)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 11:32 am)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 11:48 am)
Re: Raise initial congestion window size / speedup slow start?, Stephen Hemminger, (Wed Jul 14, 12:10 pm)
Re: Raise initial congestion window size / speedup slow start?, Rick Jones, (Wed Jul 14, 1:17 pm)
Re: Raise initial congestion window size / speedup slow start?, Mitchell Erblich, (Wed Jul 14, 2:47 pm)
Re: Raise initial congestion window size / speedup slow start?, David Miller, (Wed Jul 14, 2:55 pm)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 3:05 pm)
Re: Raise initial congestion window size / speedup slow start?, Hagen Paul Pfeifer, (Wed Jul 14, 3:13 pm)
Re: Raise initial congestion window size / speedup slow start?, Rick Jones, (Wed Jul 14, 3:19 pm)
Re: Raise initial congestion window size / speedup slow start?, Hagen Paul Pfeifer, (Wed Jul 14, 3:36 pm)
Re: Raise initial congestion window size / speedup slow start?, Hagen Paul Pfeifer, (Wed Jul 14, 3:40 pm)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 3:52 pm)
Re: Raise initial congestion window size / speedup slow start?, Hagen Paul Pfeifer, (Wed Jul 14, 4:01 pm)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 4:01 pm)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Wed Jul 14, 4:05 pm)
Re: Raise initial congestion window size / speedup slow start?, Bill Fink, (Wed Jul 14, 7:52 pm)
Re: Raise initial congestion window size / speedup slow start?, Bill Fink, (Wed Jul 14, 8:49 pm)
Re: Raise initial congestion window size / speedup slow start?, Tom Herbert, (Wed Jul 14, 9:12 pm)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Wed Jul 14, 9:51 pm)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Wed Jul 14, 10:09 pm)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Wed Jul 14, 10:29 pm)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Thu Jul 15, 12:48 am)
Re: Raise initial congestion window size / speedup slow start?, Alan Cox, (Thu Jul 15, 3:33 am)
Re: Raise initial congestion window size / speedup slow start?, Bill Davidsen, (Thu Jul 15, 8:10 am)
Re: Raise initial congestion window size / speedup slow start?, Jerry Chu, (Thu Jul 15, 10:36 am)
Re: Raise initial congestion window size / speedup slow start?, Rick Jones, (Thu Jul 15, 12:51 pm)
Re: Raise initial congestion window size / speedup slow start?, Stephen Hemminger, (Thu Jul 15, 1:48 pm)
Re: Raise initial congestion window size / speedup slow start?, Bill Davidsen, (Thu Jul 15, 4:14 pm)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Thu Jul 15, 5:23 pm)
Re: Raise initial congestion window size / speedup slow start?, Henrique de Moraes H ..., (Thu Jul 15, 7:58 pm)
Re: Raise initial congestion window size / speedup slow s ..., Hagen Paul Pfeifer, (Fri Jul 16, 2:03 am)
Re: Raise initial congestion window size / speedup slow start?, Patrick McManus, (Fri Jul 16, 10:01 am)
Re: Raise initial congestion window size / speedup slow start?, Ed W, (Fri Jul 16, 10:41 am)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Fri Jul 16, 5:36 pm)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Fri Jul 16, 6:23 pm)
Re: Raise initial congestion window size / speedup slow start?, Rick Jones, (Mon Jul 19, 10:08 am)
Re: Raise initial congestion window size / speedup slow start?, H.K. Jerry Chu, (Mon Jul 19, 3:51 pm)
Re: Raise initial congestion window size / speedup slow start?, Hagen Paul Pfeifer, (Mon Jul 19, 4:42 pm)