Gigabit network speeds

dipstick · Nov 14, 2007, 12:09 AM

Hey guys. I just finished wiring up the whole house to take advantage of a gigabit network. Everything is on Cat6 cables and running off a D-Link 4300 and a Netgear gigabit switch. There are a couple of 100 foot cables and I'm wondering if they are affecting speed throughput.
Anyways, I can't seem to break 28MB/sec transfer speeds. Windows task manager shows usage hovering at around 25-29% during heavy transfers. Does this sound ok? Seems like an awful waste of network utilization but I wont argue that its not a sh*tload better than the old 100mbps setup.
Any ideas?
Thanks

mkk · Nov 14, 2007, 04:09 AM

The harddrives at both ends need to be modern and free from doing other chores at the same time in order to be able to deliver much better performance than that, so perhaps the answer lies there. It would also take a RAID setup to deliver speeds up to the Gbit limit.

***Zardon*** · Nov 14, 2007, 04:16 AM

yeah depends on whether you mean 28mbit or 28 MB/s if its 28MB/s its probably being limited by the Hard drive and unless you are copying across the network from raid to raid it seems about right. ive a few USB2 drives and they limit at around 30-35mb/s. I would expect internal sata drive copies to be higher than 28 however, perhaps around 50mb/s. I think you need to play with HDtach and make sure that the HD limits aren't coming into play before you look at the network.

If you have 3 or 4 pcs you could try several copies at the same time to see how the network handles that.

Judas · Nov 14, 2007, 10:51 AM

I don't think you should need to worry about the footage at all

dipstick · Nov 14, 2007, 12:59 PM

Thanks guys, that totally makes sense. I feel like a fool lol. Even though all the PC's are running raid most transfers are happening off of usb2 external storage drives and HD tach confirms why my transfer speeds are what they are. Many thanks

PS. It is definitely MB/s and it seems pretty darn good to me now. Also good to hear cable length doesn't matter much

Judas · Nov 14, 2007, 03:18 PM

i think the fastest i've obtained via 100mbit pipe is something like 9.2MB/s sustained..... and with my raid 0 arrays, 1000mbit pipe, i managed 36MB/s occasionally seeing high 40s.... i think 90-100MB/s would be accurate for the highest obtainable

btw, anyone come across the 10gbit cards?

dipstick · Nov 14, 2007, 08:22 PM

yea I wasn't complaining about speeds, they're great. I was just wondering if they seemed ok since I've never been a gigabit network before. 10 gigabit would be just insane and probably totally useless for any home PC lol. I notice that every 1% of network usage is 1MB/s so it seems you are spot on with the 90-100MB/s max figure.

Judas · Nov 15, 2007, 01:36 AM

it's unfortunate that a newer TCP/IP... or something that it a new generation altogether that would further improve network utilization hasn't arrived.....

Ferret_Style · Nov 15, 2007, 06:51 PM

Ip6 came out but even if you try it i have not seen any better performance.

On the distance of CAT 6 on gigabit i think you can go up to 100m without much of an issue. Any further then that and you need to ensure good shielding on the cable as interference will really mess it up..... had a line in a house i was working on that ran behind the microwave... Was funny when they cooked dinner and the network started to go funky.

the other issue on network trafic is general windows overhead. It does not allow as full of transfers as you would think. Google limitations and i know you will find a few tweeks.

H3X4D3C1M4L · Nov 20, 2007, 10:38 PM

I recently broke this issue in half. The keyword: MTU

See... I did something similar but I have the cables in place (by the way you got ripped off with the Cat 6, Cat 5e works the same). I was worried about length, shielding, how close the wires ran to AC power etc. but it ended up being that it was the machines.

The first thing to do is find out how big the frames can be on your switch/router (I think your DLink will take 9600K frames). Then you want to enable jumbo frames on everything.

After that, get this tool DrTCP windows tcp tuning and tweaking - dslreports.com and set the MTU to something big. Example: Before my MTU was just blank meaning it used the Windows default or whatever it found. I had jumbo frames on and I was still getting garbage performance (200MBits barely at best, at worst 10Mbits!). After turning off Path MTU discovery (PMTU), changing my receive window to 256960, and making sure my receive and send buffers were as large as possible, and making my MTU 9000 well... I saw 950 MBits to every machine solid

Note that Vista is unaffected by this, during initial testing I found that I could receive really fast from that machine but not send to it very fast, changing the MTU fixed that though. I also found that Linux and BSD are largely unaffected by this... I just enabled larger buffers and fixed it.

Anyway once you do that it should spike the performance into space. Then you'll find out that your disks are much more of a limit than you ever imagined

I can give you a more full story and tell you which tool I used to measure bandwidth if you like but the end result is just what this post describes. Lucky for you I did all the grunt work

dipstick · Nov 21, 2007, 12:41 AM

Thanks a lot for the info; I will definitely look into it

Judas · Nov 21, 2007, 01:55 AM

H3X, in vista, what did you change?

PandaZ3 · Nov 23, 2007, 09:21 AM

When I asked in other forums a year and a half ago I was told it couldn't be done. Kinda steams me now! I will have to go back thru my network. I am already mostly Cat 6 with a couple of Cat 5e's and maybe one or two Cat 5's. Cat 5e and Cat 6 are just a dollar apart so I but Cat 6. I was think in of getting a dual Wan router anyway, as I have both T1 input and cable

Judas · Nov 23, 2007, 11:11 AM

xinxom...... speedy bastard of a router..

plug it in, then use a gigabit hub

the xincom 702 is suspected of showing up soon which is reported to have "gigabyte wan/lan"

H3X4D3C1M4L · Dec 22, 2007, 07:06 PM

Quote:

Originally Posted by Judas

H3X, in vista, what did you change?

Nothing. Forcing an MTU size or changing anything else did little to nothing. Vista's networking stack "learns" to adapt to the network(s) it is connected to. Its XP you gotta worry about. But I'd take a well configured XP over Vista any day.