Re: Stream BW support in Iperf

To: iperf-users --at-- dast.nlanr.net
Subject: Re: Stream BW support in Iperf
From: "Ian McDonald" <ian.mcdonald --at-- jandi.co.nz>
Date: Wed, 20 Sep 2006 11:13:14 +1200
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Does anyone know why we need multiple streams to max out the available
Bandwidth?

Why can't a single stream support high bandwidths?

Because TCP can't use all the available bandwidth due to congestion
control. There have been many attempts to improve TCP but the thing is
that loss comes in many forms, and RTT has a big impact on algorithms
too.

Try googling for TCP congestion control. You can also see the effects
by taking iperf on linux and changing the congestion control and use
netem or dummynet to do some traffic shaping. If you go to my website
you can even download versions which allow you to do this without
altering sysctls.

Ian
--
Ian McDonald
Web: http://wand.net.nz/~iam4
Blog: http://imcdnzl.blogspot.com
WAND Network Research Group
Department of Computer Science
University of Waikato
New Zealand

Follow-Ups:
- Re: Stream BW support in Iperf
  - From: Paul Hyder

References:
- Stream BW support in Iperf
  - From: Sahadevan, Samson joseph dev

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