Question about throughput

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 doesnt matter), please correct me if i'm wrong
as i feel i'm missing something in my understanding, thanks

Best Regards;

  MKamar
Received on Wed Jul 28 2010 - 06:58:24 ART