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View Full Version : Can't Seem to Transfer at Full 100Mbps



two5om
08-15-2002, 10:16 PM
Hi Guys

I am running a small LAN here and it consists of 3 PC's. They are all connected via an 8 port 100Mbps switch. I wanted to test the speed of the network so I transferred a 700MB from one Pc to another with the use of FTP software. I found that I am never able to transfer at the full 100 Mbps / 12.5MBs as I thought it would.

I have come to the conclusion that its not the following:


NIC's that I'm using on all 3 PC's as they are all 100/10Mbps cards.
It's not my switch as its a 100Mbps switch.
All the UDP cabling is fine.


Would the speed of my PC's be what's causing the data not to be transfered at full speed?

Also are there networking utilities out there that once installed will return crucial data back to me for example.... transfer rates of the files that are passing through my network as I no longer wish to use FTP software as this could also be the bottleneck in regards to my problem.

Thanx Guys.... :thumb:

Beefy
08-16-2002, 07:18 AM
The 100Mbps is the litereal speed at which data can flow across the cable. However, everytime you send information across, you aren't just sending simple files. Each file is broken up into various packets, which then all have extra information added to them, like source and destination address, frame headers and so on, which in effect take up some of your precious bandwidth. I'm not going to go into too much detail here, but that's just a quick look at that...

Also, various software configurations can cause network transfer speeds to be slightly slower than the norm too. Hard drive write speeds are another... But I wouldn't worry about it too much. Surely you can wait that little bit longer for things to transfer. If you are getting at least 3MB/s, then that is very acceptable.

If you really do want top performance, then go grab a couple 1000Mbps cards.

two5om
08-16-2002, 01:18 PM
Thanx Beefy

I know that there a lot of other factors which could be causing the data not be transferred at full speed. It's not that its major issue but when it comes to understand how things work I'm get very curious about things and want to know exactly why something is not doing what its supposed to. As for going for a Gigabit connection for my LAN, I think I'll pass on that due to the high cost and also not to mention the lack of dollar bills in my wallet and my savings account.... :)

zeradul
08-17-2002, 12:48 AM
Hard drive write speeds are another... That is the only thing Really slowing you down here. If you truely want to test the speed of you whole situation, make some ram drives, and then transfer that data from ram drive to ram drive.

As far as future capability of your Nic's and switches, keep an eye out for NIC's that are "Full Duplex Capable" which can theoretically handle 200Mbps, and switches that are the same. But until hard drives speed up, we really can't utilize all the capability of a switch with just one computer, with just one hard drive.

two5om
08-17-2002, 02:56 AM
zeradul
Please explain RAM drives to me as I'm not 100% sure of what they are and do.

As far is a know all my networking devices here are full duplex but I have a feeling that you may be right about the hard drives being the bottleneck.

zeradul
08-17-2002, 03:13 AM
Well, a ram drive is just a partition within your ram, that you can store files to. The files are deleted when you shutdown or restart. I have not used them extensively, but here is a somewhat dated tutorial on how to set one up, as well as a better definition.

http://www.speedcorp.net/guides/ramdrive/

bigjackusa
08-28-2002, 03:55 PM
First of all, you will never be able to get 100mbps because of overhead with the data transfer. 70mbps is probably the highest practical throughput. What OS are you using? Are such things as packet size optimized for lan or internet? There are free utilities on most download sites that allow you to easily tweak the necessary settings. Also the reference to 200mbps is 100 theoretical each way, simultaneously.

two5om
08-28-2002, 07:44 PM
Also the reference to 200mbps is 100 theoretical each way, simultaneously.

bigjackusa
Could you please explain your above quote, thanx mate.... :)