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Date:      Wed, 9 Jul 2003 12:29:04 -0700
From:      "Max Clark" <max.clark@media.net>
To:        "Dan Nelson" <dnelson@allantgroup.com>
Cc:        freebsd-hackers@freebsd.org
Subject:   RE: What ever happened with this? "eXperimental bandwidth delay product code"
Message-ID:  <ILENIMHFIPIBHJLCDEHKMEEKCJAA.max.clark@media.net>
In-Reply-To: <20030709190214.GL39506@dan.emsphone.com>

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> 6000000/8*.220 = 165Kbytes or 1.32Mbit/s

I understand the BDP concept and the calculation to then generate the tcp
window sizes. What I don't understand is this...

How in the world is a windows 2000 box running commercial software able to
push this link to 625KByte/s (5Mbit/s)????

How can I get similar results with FreeBSD? I don't care about any other
traffic on the network at the same time as my transfer, just the raw
performance of my transfer.

Thanks,
Max

-----Original Message-----
From: Dan Nelson [mailto:dnelson@allantgroup.com]
Sent: Wednesday, July 09, 2003 12:02 PM
To: Max Clark
Cc: freebsd-hackers@freebsd.org
Subject: Re: What ever happened with this? "eXperimental bandwidth delay
product code"


In the last episode (Jul 09), Max Clark said:
> When you say it's got a specific purpose, I am looking for something
> that will dynamically tune a 6Mbit/s, 220ms network link for bulk
> (500MB) file transfers. Is this what I think it is, or should I be
> looking at something else?

Unless you're doing multiple simultaneous TCP connections it'll only
slow you down.  Your bw*delay product is 6000000/8*.220 = 165Kbytes, so
telling ncftp to set its so-bufsize to say 200K, and telling your ftp
daemon to do the same thing, should be all you need.

--
	Dan Nelson
	dnelson@allantgroup.com



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