RE: Question about throughput

Thanks Chris;

   It's really helpful, can i know from which website you get these results?,
I can see the results in the excel sheet close to the results i got from the
below formula (Note that calculation below in bits, and in bytes in excel
sheet), But the good and the new thing is that it takes the looses into
consideration, But the best thing is to know the formula/equation used :D

Best Reagrds;

  Mohamed Kamar

Date: Wed, 28 Jul 2010 14:51:57 -0500
Subject: Re: Question about throughput
From: cgrammer_at_essilorusa.com
To: mohamed_kamar_at_hotmail.com
CC: ccielab_at_groupstudy.com

I made the attached excel spreadsheet to help explain transfer times based
upon several mathematical models I found on various websites.
Maybe this will help :)

I dont know if group study allows attachments so If you would like the excel
send me an email and I will send it to you

Chris

On Wed, Jul 28, 2010 at 1:58 AM, mohamed kamar <mohamed_kamar_at_hotmail.com>
wrote:

Dears;

 I have question regarding throughput , let's say for example if I have 20M
link, it doesn't mean that i can download 1 GBit file in 50sec, The
throughput
equation I've found is

 Max TCP throughput = RCV buffer size / RTT =? bps

7 Regarding the RCV buffer size, In Windows Server 2003, Windows XP,
and Windows 2000, the Transmission Control Protocol/Internet Protocol
(TCP/IP)
stack tunes itself in most environments, using larger default window sizes
than in earlier versions of Windows so we can assume the maximum here which
is
64K.

7 For RTT let's assume it's 200ms to the site i want to download from

The Question, If what stated before is correct, that means under all
circumstances I can't take throughput above 64*8/.200=2560Kbps=2.56Mbps or I
can only download the 1GBit file in 1*1024/2.56=400 sec regardless what's
contracted BW is (20M or 100M doesn t matter), please correct me if i'm wrong
as i feel i'm missing something in my understanding, thanks

Best Regards;

 MKamar
Received on Thu Jul 29 2010 - 11:50:44 ART