Just stepped up to gigabit lan speed

[prouton]

I've started working with trimming recordings and burning them to DVD, and find it so much easier to use a separate piece of software and my main computer, but moving files over from the PVR computer was certainly slow. For a typical 2GB file ( one hour of medium quality SD) it was taking Windows seven full minutes.

So I started looking into adding gigabit NICs to both machines and connected them through a gigabit switch. Now I'm usually one of the most frugal people when it comes to buying computer gear (my main computer is a five year old system running an Athlon XP 2400+), but a common theme to the stories I was seeing is that gigabit hardware is not necessarily the place to be shaving pennies. If you want it to work right out of the box, and to keep working, don't buy off-brand or bargain basement NICs and switches.

Office Depot ran the D-Link DGS-2205 switch in their ad this week for $30, and D-Link themselves has a $10 rebate through the end of the month, so I couldn't resist. I'm skirting the limits of my own rules about not buying cheap equipment (I've been involved with lots of D-Link routers arriving or going bad in the last few years, so they aren't my favorite brand these days), but since it's generally reviewed well, I went with it.

For NICs, I went with what seems to be the safest bet for all around compatibility and reliability and bought Intel. I found the PCI PRO/1000 GT Desktop Adapter (PWLA8391GTBLK) at Newegg.com in an OEM version for only $26.19 each (sorry, the price is back up to $28.19) and free shipping.

All together, I've got the two computers lashed together at high speed for less than $80. And just how much performance did I get for that price? What used to take Windows seven minutes to do now takes...60 seconds! Hell, I might just start doing regular backups of my main computer (to the PVR).

[pBS]

i bet you didn't have the network 'tweak' setup if it was taking you 7 minutes to transfer a 2 gb file...
should even make your gigabit about 30% faster for free..

search for the Tcp1323Opts registry setting...a new protocol that is enabled if both sides have it enabled, made specially for large files and media streaming...
main thing is file transfers jump up to full utilization which isn't possible past 50% otherwise...

here's a reg file if you'd like to try for xp..

Code:

REGEDIT4

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
"TcpWindowSize"=dword:000f4240
"Tcp1323Opts"=dword:00000001
"DisableTaskOffload"=dword:00000000

all 3 are usefull, but only #2 is needed to get the speedup...tho the others do help on slower connections..
[you can delete those lines if don't want to change them]
i'm curious to know if they help gigabit as much as 100m..
[go from 50% utilization to 80-90% ]
look in taskman to see how much of your bandwidth is being used during transfers...

[csy]

Be carefull with TCP receive-window (RWIN) sizing and scaling. Different operating systems have varying TCP features and capabilities.

For a starter RFC1323 is enabled by default on WinXP, however setting
"Tcp1323Opts"=dword:00000001
will disable the timestamp feature, so not a good idea.

Increasing the TCP window size can provide substantial throughput improvements over high-bandwidth and/or high-latency TCP connections (eg international downloads/transfers), also commonly known as the "bandwidth delay product", however MS Windows versions prior to Vista tend to have application issues when RWIN>64KB. In particular IE7 is prone to random hangs when you click on links.

On a final note, MS Vista has auto-tune TCP, so automatically optimises RWIN "out of the box". Same applies for the latest Apple OS (Leopard)

Good references:
http://en.wikipedia.org/wiki/TCP_Tuning
http://en.wikipedia.org/wiki/TCP_window_scale_option

[zehd]

Be carefull with TCP receive-window (RWIN) sizing and scaling. Different operating systems have varying TCP features and capabilities.

YES be careful. It's those very tweaks that made it impossible for me to use MVPMC. Thanks a lot tipster :mad:

Anyway, I'm getting 80% of a 100BaseT connection with completely default parameters on two windows xp pro computers and a basic router.

It has made me think that even before my famous tweak episode, something else was causing a slow down. But I'm very sure the TCP tweaks were deadly...

[gazoo]

It takes me about 5 mins to transfer that. On the windows task bar graph, it doesn't really say the correct % however (at least for me). I believe I was doing ~50mbps (that's bits, bytes would have been 6.25 mBytes). So around 50% utilization for me. Don't know what the deal is with my LAN either, but 50% seems to be the average of what I get on 100BaseT.

EDIT/CORRECTION: I can get hit 90%, just ran it a few more times.

[prouton]

I'd already been using "TaskOffload" on the 100baseT (motherboard) adapters, and I'm a little unsure about going to extremes on the RWin value for the reasons mentioned.

The Intel NICs were a bit of a surprise in that there are lots of things that can be set/optimized when you go into the connection's "Properties" and click on "Configure" for the card (including the TaskOffload setting, with explanation of the purpose). Since all the new hardware supports it, I'm using 9000k jumbo frames, so the RWin and Tcp1323Opts settings may be meaningless anyways in this environment. I may look into this issue in my copious *cough* free time.

I did end up with a problem out of all of this. I hadn't tried to use my MVP until today, and ended up with lots of hesitancy hiccups. I tried turning off jumbo frames, and looking for other settings to change, but those things didn't fix it. However, when I removed one switch from the path (immediately before the MVP, the problem stopped. Now, I've had no problems with this switch in couple of months it's been in place, and it isn't connected directly to the new gigabit switch, so I'm not sure why it's all of a sudden getting hairballs.

My network currently is: main computer and PVR computer connected to the D-Link gigabit switch. That switch uplinks to an Edimax (CompUSA) 100BaseT router (I think I mentioned in the first post how cheap I am?). The Edimax also has a SimpleTech NAS and Airlink AR430W router (neutered to be just a 100BaseT switch and 54g wireless access point) attached. It's through the Airlink that the MVP is attached (wired). Before the gigabit stuff went in, no hiccups.

I'm not sure yet what I'm going to do longterm, as I really wanted the access point in that room. Oh well...

[zehd]

EDIT/CORRECTION: I can get hit 90%, just ran it a few more times.

maybe that was cause some info was cached...