[70345] in North American Network Operators' Group
Re: WAN transfer rates
daemon@ATHENA.MIT.EDU (Iljitsch van Beijnum)
Tue May 11 05:19:34 2004
In-Reply-To: <20040511082432.GA57413@jnull.rackspace.com>
Cc: nanog@nanog.org
From: Iljitsch van Beijnum <iljitsch@muada.com>
Date: Tue, 11 May 2004 11:19:07 +0200
To: Jeff Nelson <jnelson@rackspace.com>
Errors-To: owner-nanog-outgoing@merit.edu
On 11-mei-04, at 10:24, Jeff Nelson wrote:
> I realize that transfer rates across the Internet diminish
> significantly
> with latency, but what's the good answer for someone shrunk down to
> <10Mbps when the smallest pipe between them is 100Mbps and latency is
> <40ms?
> Does anyone have reference to any study done in this area? I'm sure
> window tuning can alter this, but I'm interested in average statistics.
The best you can do is transfer a window size per round trip. You can
see the window size with tcpdump or one of its cousins, and looking at
netstat output will get you somewhere in the neighborhood too. So if
your window is 16k and your RTT 25 ms, that's 16k every 25 ms. Or 16 *
1000 / 25 = 640k per second = 640000 * 8 = 5 Mbps.
