Gigabit Network – Test

gigabitnetworking

I have a very basic and newbie question. I was told that we have a "Gigabit Network". So, I ran a quick scp test by copying a file to another machine and the transfer rate is only 35MB/sec.

Shouldn't the transfer rate be near the 1GB/sec?

Also, is there a command line that will tell me that I have a "Gigabit network"? Eg. will ifconfig tell me that?

Best Answer

GigaBIT Ethernet is 1 billion BITS per second. Theoretical maximum transfer is 125MB/sec.

Having said that, your 35MB/sec is a bit slow, but encryption is going to slow down SCP file transfers and that probably accounts for it.

Encryption aside, any file transfer is a poor network benchmark as your I/O subsystem may be bottlenecking the transfer, though. You mention ifconfig, so I assume you're running some *nix OS. Have a look at the ttcp utility. It gives a nice measure of TCP throughput on your network.

Related Solutions

Unexplained slow gigabit network speeds

Try disabling Window's auto-tuning feature.

In a CMD window:

netsh interface tcp set global autotuning=disabled

Re-run your test, and see if you notice a performance improvement. I've had to do this on a couple of laptops running Windows 7 in my house, and it's helped.

If things get worse, or you don't notice any improvement, you can re-enable autotuning by:

netsh interface tcp set global autotuning=normal

What would make a PowerConnect Gigabit switch run at 100 Mbit speeds

What are you testing the link to link endpoints for speed? I mean, are all your links you're testing between 1 Gbit? You can only get 1 Gbit between two or more machines with gigabit network cards. The router will never go above 100 Mb since you said that's what it at most supports (so your wireless connections will be stuck going through a straw connecting to a firehose anyway).

If your workstations have gig cards and you can verify that they're working properly, you can try manually setting them to a gig connection full duplex, disabling the auto negotiation.

You might also want to test your wiring to the switch to make sure the wires and connectors are secure and of high quality.

It is possible the linksys is interfering; it looks like we had an issue where someone had a small hub for testing some systems hooked up to a Cisco switch in our MDF room and it caused all sorts of problems where the switch was confused because of that hub having multiple systems coming off one port. Why? I don't know, I didn't handle the issue, just had the report after the fact, but I know it caused at least one room to have huge connection and performance issues between their lab and the NAS in another building. The best way to test that is disconnect the linksys from the switch and see what 2 or more wired workstations are getting for performance in transferring files and pinging each other after a reboot or two (and restart the switch) to flush cached tables and such.

Best Answer

Related Solutions

Unexplained slow gigabit network speeds

What would make a PowerConnect Gigabit switch run at 100 Mbit speeds

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