Gigabit Networking

[Carl 3]

Anyone here wired up there own cat6 Gigabit LAN???

I just replaced our switches and our pc nic's in our home LAN to Gigabit gear - we've got 3 pc's and 2 laptops with Gigabit nic's - and I test transferred 10GB in 8 mins...that's only 170Mb/s...previously it took 10 mins so it was faster but not by much!

While I know speeds are ultimately limited to the HDD's, the sources read is 1.5Gb/s and the targets write (burst) is 560Mb/s, so 170Mb/s seems awefully slow. The cabling between them is cat6, length is under 100m, there is a Gigabit switch between them, the switch and network connections say they're connected at 1Gb/s.

Done some reading today and the only thing I can think that would be causing slow down is the RJ-45 (8P8C) connectors, since I wired them myself, as it seems that the length of untwisted wire allowed should be less than 1/2"...that's f**king hard to do and since there's 4 self wired connectors in the connection (PC-switch-PC) there could be a bit of Near End Cross Talk...

Are there special cat6 connectors that make wiring easier???

Anyone got a cat6 cable tester???

Is 170Mb/s actually okay given that full duplex ethernet is theoretically 200Mb/s???

Come on geeks, I know there's a few here, thoughts???

[ipwnyou 0]

You have to take into account other things such as the quaility of the switch you're using, the network cards, and the bus speed of the computers (i.e. the PCI version, and 32bit vs. 64bit) as here at work we're using 64bit Cisco network cards, though CAT6 cables (Made by me, but i'm certed), into machines running the Seagate Cheetah Ultra 320 SCSI drives (15000 RPM at memory) in RAID - though a Fully managed Cisco gigabit switch, and I can pull straight file trasnfers of up to 10GB / 3 Mins (just did a quick copy on our database server) but this is on Windows Server 2003 / 2007 - the other bottleneck (and the most likely one) is Windows - specifically Windows XP. I cant remember where I read it, but there's a way to tell windows to not throttle its network - like if you copy a file, and while it's copying go into Task Manager and look at your network usage, it probably wont even be near 10% - there's a way to bring that up. Server 2003 just goes for it.

But to answer your question about your cable - yes, your wiring can definately affect your speeds, but you'd have to have wired it with your eyes shut to dramatiacally affect your speeds. Also, check the quality of your RJ45 ends - some have a very small little pin that penetrates the wire, and some have a massive 4 or 5 pronged copper bar that splits it for maximum contact - I use those.

[ipwnyou 0]

Oh and are you running them directly from the PC to the switch, or do you have RJ45 jacks?

[Carl 3]

Running D-Link nics directly to a Cisco switch. It's XP and the cable is high quality cat 6.

IMHO, I expected speeds of 400Mb/s which is fair given the read/write speeds and the PC's. 10GB in 3 mins is ~450Mb/s so it's not unrealistic.

The more I think on it the more i'm convinced I need to get decent cat6 RJ-45's that have a loading bar to reduce the untwisted distance, however, if it were just a windows setting then that'd help!

Edited April 19, 2007 by Carl

[Carl 3]

I must be bored, but i've read up more and TCP window size is a big culprit as default windows 2k and XP use a size designed for 10Mb/s LANs!!!

[nz320i 0]

hey you can buy cat6 clipsal, or krone ( better ) jacks at electrical stores, bends cant be sharp in the cable and the wires have to be twisted as much as possible!

I did a job last year which was a lot of cat 6 wiring, so much harder than cat5!

Glad I'm not doing that anymore!

Also the windowing in TCP/IP, can it be changed so windows are bigger?

How much was the Cisco switch?!

[QuickSilver 0]

I had a cat5 cable set up all through my house (2 laptop's, 2 desktops) all wall jacks etc etc, running under house,

recently got a new switch, ran cat6 cabling and ive just put a switch centrally located under the house which has a wireless access point connecting to it, this beams up to the laptops, and cabling still works, laptops are then mobile, and security is not wep etc, just mac adress access.... i can go technical, but everyones done that already im just adding my 2 cents. bottom line, cables good, wireless good, fast internet, good. entire house wired up to each others computer handy

[Carl 3]

hey you can buy cat6 clipsal, or krone ( better ) jacks at electrical stores, bends cant be sharp in the cable and the wires have to be twisted as much as possible!

I did a job last year which was a lot of cat 6 wiring, so much harder than cat5!

Glad I'm not doing that anymore!

Also the windowing in TCP/IP, can it be changed so windows are bigger?

How much was the Cisco switch?!

Had a fiddle with the window sizes last night and the throughput increased, seems that MS Windows is the culprit. The TCP/IP window sizes can be increased, I set them 10x larger and 10GB took 5mins (266Mb/s) so almost doubled the speed. I think the connectors still need fixing though as that's still lower than perfect.

The TCP/IP sizes can be increased along with the buffers and other stuff although buffers are not as necessary in LANs due to the low latency.

We've got two 8 port switches, the Cisco switch is a LinkSys, the other is a D-Link, both were $140ish through an admin account, normal retail is $200ish.

[Andrew 30]

Was going to say buffer problems ... we moved from GB at work to iSCSI - we are getting huge throughput now.