Re: [Nolug] LAN speed confusion

From: Chris Jones <>
Date: Fri, 13 Jul 2012 19:23:35 -0500
Message-Id: <>

It's because your logic is off. 100mbps is roughly 12MBps. 100MBps Ethernet maxes out at 12MBps in any one direction. Full duplex means you can have simultaneous 2way communication. In theory this could double your speed, assuming both ends are sending each other equal amounts of data. But this is rarely the case. It usually involves a computer reading or writing data to/from another computer. The remote computer usually has no interest in the client. It's only concerned with receiving data and storing it, or presenting that data when it is requested. So all you're going to see is 12MBps. I also doubt your Internet is 25MBps. It's probably 25Mbps, which is roughly 4MBps.

Chris Jones
Network Engineer

(504) 274-1361

On Jul 13, 2012, at 5:26 PM, Ron Johnson <> wrote:

> I've got a bunch of devices at home connected to a Fast Ethernet switch. Among them are a Netgear switch (aku), my Linux desktop (haggis) and my wife's Linux desktop (peanutbutter). So, I should get a theoretical max of 12MBps in half-duplex mode and 25MBps in full-duplex mode.
> That's presumably why internet speed tests on both haggis and peanutbutter show peaks up to 24MBps (close enough to my paid-for max of 25MBps).
> Why, then, do xfers (NFS, scp & plain old ftp) between haggis and peanutbutter max out just under 12MBps?
> Ron
> --
> "There is usually only a limited amount of damage that can be
> done by dull or stupid people. For creating a truly monumental
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> Thomas Sowell
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Received on 07/13/12

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