My attachments were a bit too large, I have put the attachments referenced below up at this site temporarily:
http://216.248.62.108/wireshark/
-----Original Message-----
From: Aaron Allen
Sent: Wednesday, September 10, 2008 10:39 AM
To: 'Community support list for Wireshark'
Subject: RE: [Wireshark-users] TCP Window Sizes
Sake,
Sorry, to be more clear:
Windows 2008 -> Amazon (this is where I'm seeing problems) Vista Workstation -> Amazon (I consistently get 8-10mbit)
I've attached local and SPAN packet captures from two uploads to S3. The "largewindow" captures are from the Vista workstation and the "smallwindow" captures are from the windows 2008 server.
The NIC in the server is an Intel Pro 1000 MT and I have disabled "Large Send Offload" (which is intel slang for TCP segmentation offloading). Of course, drivers are updated.
Hansang,
I see what you are talking about when I look at the TCP graphs. Netstat -t is showing the connections in state "InHost" which would eliminate the possibility of offload problems (I assume?).
I'll admit, I'm confused. I see larger window sizes in the packet captures from the Vista workstation, but not from the Windows 2008 server. The packet captures from the local and SPAN session vary greatly from the Vista machine. Since that NIC has "Large Send Offload" enabled, I'm guessing the workstation NIC is handling segmentation, and thus the differences.
Is it possible that this is an application limitation? I really thought this should all be transparent to the app.
Thanks for all your help!