Windows Server - Windows 2008 x64 SP2 & R2 RDP Networking Issue

Hi All,

I have a networking related issue on my windows 2008 SP2 x64 & R2 terminal
servers here you are the details:

All the terminal servers are DELL M605 Blade servers with 32 GB RAM and two
quad core AMD processors.

The first server is working well with windows 2008 SP2 Enterprise 32 bits
and with a broadcom 10GbE nic updated to the last driver version. The apps
are running very well accesing to  a database Windows 2003 SP2 Standard 64
bits server with SQL 2008.

The second server has networking issues with  windows 2008 SP2 Standard 64
bits with a broadcom 10GbE nic updated to the  last driver version. The apps
are running very slow accesing to the same database server described
before.The only apps that run fine from this server is our intranet based on
MOSS 2007 SP2 with its databases on the same database server and outlook 2007.

The third server has networking issues with  windows 2008 R2 Standard 64
bits with a broadcom 1GbE nic updated to the last driver version. The apps
are running very slow accesing to the same database server described before.
This server was recently installled from the scratch.

I copied a folder of 300 MB from the 3 servers to the same database server
and the transfer rate was very much better from the first server -10mb/sec-
than the others-350k/sec-.

The only difference that I note is the server flavor -W2k8 Ent 32 vs W2K8
SP2 R2 Std 64-

Any idea will be appreciated.

Best regards.

I solved the issue with an intensive search and I found the following:

Since Windows Vista MS optimizes the TCP throughput, especially for
transmission paths with a high BDP, the Next Generation TCP/IP stack supports
Receive Window Auto-Tuning and some network are not ready to such changes.
So, recently we changed the core network switch in order to scale our
bandwith to 10 gigabits. We are in contact with our hardware supplier in
order to assure us that the new device supports the "Receive Window
Auto-tuning" parameter. In the meantime we disabled the parameter in the
servers with networking issues and now the servers are working fine. The
command to perform that task is: NETSH--->INTERFACE---->TCP---> SET GLOBAL
AUTOTUNING=DISABLED.

http://blogs.msdn.com/wndp/archive/2007/07/05/receive-window-auto-tuning-on-vista.aspx

http://support.microsoft.com/kb/934430/en-us

http://technet.microsoft.com/en-us/magazine/2007.01.cableguy.aspx

The only thing that is oddy is why the server with windows 2008 Ent 32 bits
is working well when it has enable such parameter? Is there some networking
guy that can explain that for the community benefit?

Thanks a lot to MS and its contributors for the excellent links!!!