Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

How TCP/IP Sliding Window is configured on Win7 hosts?

Posted on 2014-01-31
4
Medium Priority
?
16,244 Views
Last Modified: 2014-02-07
How to set the TCP window size in Windows 7?  Environment Variables or Registry Entry? How to set adjust parameters (like TCP window size) in Windows 7 to improve network performance over LAN & WAN?
0
Comment
Question by:helpdesk_wlk
  • 2
4 Comments
 
LVL 84

Expert Comment

by:David Johnson, CD, MVP
ID: 39825629
Windows Vista and newer use it by default .. They call it auto-tuning
0
 
LVL 6

Accepted Solution

by:
Sasha Kranjac earned 2000 total points
ID: 39825672
TCP Window Size can be adjusted editing the Registry, and it works back from NT times, for all Operating Systems, not just for Windows 7. Well, it should work - I've tested it on NT 4, Windows Server 2003 and Windows 7. I'm pretty sure it would work on Windows Server 2012 R2 and Windows 8.1 too.

You can set TCP Window size either A) globally, for all interfaces or B) per interface.

A) Run Regedit and under following key

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
add GlobalMaxTcpWindowSize REG-DWORD entry. Put any value between 0x0 and 0x3FFFFFFF.

B) Run Regedit and under following key:

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\ interface-name
add TcpWindowSize REG-DWORD entry. Put any value between 0x0 and 0x3FFFFFFF.

A lot of factors affect transfer rate and each network should be fine tuned - there is no "recipe for all". Bit errors, round-trip time, network bandwidth, sender/receiver configuration and many other factors have impact on network performance.

To check TCP/IP stack configuration on Windows 7 type in command prompt:

netsh interface tcp show global
netsh interface tcp show heuristics
Take a look at the two lines:
Receive Window Auto-Tuning Level : normal. It means OS is using TCP/IP normal level of auto-tuning.
Windows Scaling Heuristics : enabled tells you auto-tuning is enabled.

Be very careful and calculate TCP window size to avoid network performance penalties.

Check these sites for more info: TCP thoughoutput calculator, Brad Hedlund's Blog and Neil Carpenter's Blog
2
 

Author Comment

by:helpdesk_wlk
ID: 39841033
Thank you for your answers.
0
 
LVL 6

Expert Comment

by:Sasha Kranjac
ID: 39841311
You're welcome!
0

Featured Post

Windows Server 2016: All you need to know

Learn about Hyper-V features that increase functionality and usability of Microsoft Windows Server 2016. Also, throughout this eBook, you’ll find some basic PowerShell examples that will help you leverage the scripts in your environments!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This is the first one of a series of articles I’ll be writing to address technical issues that are always referred to as network problems. The network boundaries have changed, therefore having an understanding of how each piece in the network  puzzl…
This article offers some helpful and general tips for safe browsing and online shopping. It offers simple and manageable procedures that help to ensure the safety of one's personal information and the security of any devices.
This video Micro Tutorial explains how to clone a hard drive using a commercial software product for Windows systems called Casper from Future Systems Solutions (FSS). Cloning makes an exact, complete copy of one hard disk drive (HDD) onto another d…
With the advent of Windows 10, Microsoft is pushing a Get Windows 10 icon into the notification area (system tray) of qualifying computers. There are many reasons for wanting to remove this icon. This two-part Experts Exchange video Micro Tutorial s…

773 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question