Strange gigabit network issue

[BD2003]

Just set up my newfangled gigabit network, and I'm having a few issues.

Theres three computers in question, a desktop, server and HTPC.

The desktop has an onboard marvell 88E8053 gigabit NIC.
The server and HTPC have identical new trendnet (realtek RTL8169) PCI gigabit NICs. Onboard on those PCs is only 10/100, so I've disabled them.

The desktop and server are in one room, connected to a D-Link DGS-2205 Gigabit switch.
Theres a cat6 line running out to the living room connecting to a trendnet switch there, to which the HTPC is connected.

Everything is connected using absolutely brand new Cat6 cables, and the switch shows the green light for gigabit connection for everything.

The server and HTPC can send and/or receive with each other at ~60mb a sec. Works beautifully.

Now the problem:

The desktop can only receive at ~15mb a second from either. Despite that, it can send at ~60-70mb a sec to either one. Often when sending/receiving between the desktop and the server or htpc, the connection can hang for a few seconds in the middle of the transfer.

Originally I thought maybe the PCI NICs I bought just sucked at sending, but they send fast (60mb) to each other, only slow to the desktop.

I've disabled jumbo frames on the server and HTPC, since it didnt seem to make a difference, and was fast enough already. The options are disabled, 2KB MTU, 3KB MTU....7KB MTU.

On the desktop, theres an option for "jumbo packet", with choices of 1514 bytes, 4088 bytes and 9014 bytes. I have it set to 1514.

The only other thing I've noticed that might have something to do with it - on the desktop, the choices for transmit or receive buffers is either 256 or 512. On the server/htpc, the max transmit buffers is 128, and max receive buffers is 512.

Is it possible that these two different NICs are just not compatible with each other, or is there something I'm missing?

 

[spidey07]

No, not possible the NICs aren't compatible. Standards are a good thing, unless it's a driver problem.

Try disabling pause frames if you can on the desktop, should be in the network control panel. And to make troubleshooting easier, put everyting on a single switch. Not saying that is a problem, but it will help determine what is going on.

 

[cmetz]

How are you testing "transfer"? Test methodology matters a lot.

Try forcing all systems to 100Mb/s - does everything look right then?

Try connecting systems directly with a cable.

Check for driver updates.

In general, I hate the RealTek NICs and would urge you to throw them out. Intel Pro/1000 NICs are cheap in the grand scheme of things ($30-$40) and better hardware with better drivers - they just work.

 

[BD2003]

Well, I think I've at least narrowed it down to a driver issue. All three PCs usually run Vista, but I have the desktop also running OS X. Under OS X, the desktop can send/receive at full speed to both PCs that it has an issue with.

The driver I'm using in Vista is from 5/20/08 over windows update, so its not recency. Its probably some setting - I dont have a setting for "pause frames" though.

 

[cmetz]

It could also just be Vista. Wierd performance problems seem to just go with the territory with Vista, some things work great and others don't work right even though they should.

 

[JackMDS]

Try the following (only for Vista).

Download TCPOptimizer, http://www.speedguide.net/downloads.php

Check the current setting of TCP Auto-Tuning

From a command prompt with administrator privileges.

Issue the command: netsh interface tcp show global

Output should look like this:

Querying active state?
TCP Global Parameters
----------------
Receive-Side Scaling State: enabled
Chimney Offload State: enabled
Receive Window Auto-Tuning Level: normal
Add-On Congestion Control Provider: none
ECN Capability : disabled
RFC 1323 Timestamps : disabled

***Notice that Receive Window Auto-Tuning Level states Normal.
That means that it is On.

----------------------------

Disable TCP Auto-Tuning

From a command prompt with administrator privileges.

Issue the command: netsh interface tcp set global autotuning=disabled

Run again the show global as above and it should state:

Receive Window Auto-Tuning Level : disabled

-------------------------
At this point Run TCPOptimizer, and set the TCP/IP parameters according to your Internet connection contract Speed.

Try first the RWin size as indicated by the program, measure the Download. Then try double the size of the recommended RWin.

Choose whatever seems to work best for you.

-------------------------------
If you need to reverse the status of the RWin

Enable TCP Auto-Tuning

From a command prompt with administrator privileges.

Issue the command: netsh interface tcp set global autotuning=normal

For Win XP this page would do:

Optimizing the TCP/IP Stack - http://www.ezlan.net/Internet_Speed.html

 

[BD2003]

Originally posted by: cmetz
It could also just be Vista. Wierd performance problems seem to just go with the territory with Vista, some things work great and others don't work right even though they should.

I doubt that. Thats just a lazy explanation, pointing the finger at an OS that gets a bad name because of that very laziness. All three computers are running Vista, and two of them arent having any LAN issues.

 

[BD2003]

Originally posted by: JackMDS
Try the following (only for Vista).

Download TCPOptimizer, http://www.speedguide.net/downloads.php

Check the current setting of TCP Auto-Tuning

From a command prompt with administrator privileges.

Issue the command: netsh interface tcp show global

Output should look like this:

Querying active state?
TCP Global Parameters
----------------
Receive-Side Scaling State: enabled
Chimney Offload State: enabled
Receive Window Auto-Tuning Level: normal
Add-On Congestion Control Provider: none
ECN Capability : disabled
RFC 1323 Timestamps : disabled

***Notice that Receive Window Auto-Tuning Level states Normal.
That means that it is On.

----------------------------

Disable TCP Auto-Tuning

From a command prompt with administrator privileges.

Issue the command: netsh interface tcp set global autotuning=disabled

Run again the show global as above and it should state:

Receive Window Auto-Tuning Level : disabled

-------------------------
At this point Run TCPOptimizer, and set the TCP/IP parameters according to your Internet connection contract Speed.

Try first the RWin size as indicated by the program, measure the Download. Then try double the size of the recommended RWin.

Choose whatever seems to work best for you.

-------------------------------
If you need to reverse the status of the RWin

Enable TCP Auto-Tuning

From a command prompt with administrator privileges.

Issue the command: netsh interface tcp set global autotuning=normal

For Win XP this page would do:

Optimizing the TCP/IP Stack - http://www.ezlan.net/Internet_Speed.html

Well, this is a LAN issue, not an internet issue - is stuff like RWIN even relevant?

 

[JackMDS]

You ask for advise and I gave one, it is your call.

 

[BD2003]

Originally posted by: JackMDS
You ask for advise and I gave one, it is your call.

Don't get me wrong, I'm not being ungrateful. Only one way to find out I suppose.

 

[spidey07]

Originally posted by: cmetz
It could also just be Vista. Wierd performance problems seem to just go with the territory with Vista, some things work great and others don't work right even though they should.

but, but, but...We're Microsoft! Our stack doesn't need to adhere to no friggin' standards!

 

[mcmilljb]

Also consider getting the desktop nic's driver from the motherboard's maker. Microsoft Update's drivers sometimes do not work very well. I had a laptop from Dell, and Microsoft Update always wanted to use its video driver. I would have problems if I used it so I just ignored it and always used the Dell driver.