Difficulty Downloading ITMS via SIM

[Migration User]

http://www.vistax64.com/tutorials/72308-auto-tuning-tcp-ip-receive-level.html 

I was having a lot of trouble downloading the 3 GB for my new ITMS software. SIM would work until the d/l was approx 50% complete, then it would slow to a crawl, and finally time out. Support could not help me because it was too easy to say that the problem was in my network/firewall/load balancing/ISP. I could not disprove any of those enough to satisfy support.

They were correct that the problem was on my end, though! My attached atricle (ignore that it is for Windows Vista, it worked for W2k864bit OS) showed me how to change the "Auto-tuning" setting for my NIC. (and how to set it back) I was finally able to complete my download.

 

After 10 days of fighting with SIM, I can finally focus on Installing and migrating my v6 NS.

 

My google search that got me to my answer was:   receive window auto-tuning level disable

 

To Set= netsh interface tcp set global autotuninglevel=disabled
Undo change= netsh interface tcp set global autotuninglevel=normal
 

[Migration User]

Support could not help me fix the issue, because it was ON MY SIDE. They were able to help me narrow down where the problem was. It was on my end, on my server.

 

I was able to d/l huge files from Microsoft's MVLS site, so I initially thought it was a Symantec issue, but Microsoft's downloads must have a way to use the autotuning setting without degrading the transfer speed.

[JoeVan]

I would use caution when disabling autotuning.  In general autotuning is a good thing that will increase download performance. 

I believe when the autotuning feature exposes an issue, its usually because of some other problem in your environment such as a NIC driver or one of your network infrastructure devices that isn't compliant with RFC 1323.  We ran into a similar issue on one server after switching from an Intel NIC to a broadcom NIC and had to disable TCP offloading to solve the issue.