(Windows auto-tuning uses TCP window scaling dynamically.) For special network appliances, like firewalls, proxies, accelerators, etc., they might 'transparently' sit in the middle of a TCP flow, and if they don't support TCP window scaling (used by Windows auto-tuning), auto-tuning cannot function as intended. A TCP SYN packet is retransmitted more than one time over the TCP connection. The TCP connection is created by a client that does not support the TCP window scaling feature. For example, the TCP connection is created by a computer that is running Windows XP.
Windows 10 Tcp Tuning
-->Bios xbox. This article describes how the Receive Window Auto-Tuning feature improves data transfer, how to enable/diable this feature for HTTP traffic on Windows Vista-based computers, and issues that may occur after you enable this feature for HTTP traffic.
Original product version: Windows Vista
Original KB number: 947239
Introduction
Windows Vista includes the Receive Window Auto-Tuning feature that improves performance for programs that receive TCP data over a network. However, this feature is disabled by default for programs that use the Windows HTTP Services (WinHTTP) interface. Some examples of programs that use WinHTTP include Automatic Updates, Windows Update, Remote Desktop Connection, Windows Explorer (network file copy), and Sharepoint (WebDAV).
If you enable Receive Window Auto-Tuning for WinHTTP traffic, data transfers over the network may be more efficient. However, in some cases you might experience slower data transfers or loss of connectivity if your network uses an older router and firewall that does not support this feature. For example, when you use Windows Internet Explorer to access applications that are hosted in Microsoft Office SharePoint Server, the HTTP traffic may slow down. This occurs because certain routers do not support the Receive Window Auto-Tuning feature.
Note
Since the release of Windows 7, Receive Window Auto-Tuning is now available for programs that use the Windows Internet (WinINet) application programming interface (API) for HTTP requests instead of WinHTTP. Some examples of programs that use WinINet for HTTP traffic include Internet Explorer, Outlook, and Outlook Express.
How Receive Window Auto-Tuning feature improves data transfer
The Receive Window Auto-Tuning feature lets the operating system continually monitor routing conditions such as bandwidth, network delay, and application delay. Therefore, the operating system can configure connections by scaling the TCP receive window to maximize the network performance. To determine the optimal receive window size, the Receive Window Auto-Tuning feature measures the products that delay bandwidth and the application retrieve rates. Then, the Receive Window Auto-Tuning feature adapts the receive window size of the ongoing transmission to take advantage of any unused bandwidth.
Enable Receive Window Auto-Tuning feature for WinHTTP traffic
Note
Prerequisites: You must be running Windows Vista Service Pack 2 or Windows Vista Service Pack 1, or have hotfix 939006 installed to enable auto-tuning for WinHTTP.
Important
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: 322756 How to back up and restore the registry in Windows
To enable the Receive Window Auto-Tuning feature for HTTP traffic, you must edit the registry. To do this, follow these steps:
- Click Start, type regedit in the Start Search box, and then press ENTER.
- Locate and then right-click the registry subkey
HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionInternet SettingsWinHttp. - Point to New, and then click DWORD Value.
- Type TcpAutotuning, and then press ENTER.
- Right-click TcpAutotuning, and then click Modify.
- In the Value data box, type 1, and then click OK.
- Exit Registry Editor.
- Restart the computer.
The Receive Window Auto-Tuning feature is enabled for HTTP traffic if the TcpAutotuning registry entry is set to 1. The Receive Window Auto-Tuning feature is not enabled for HTTP traffic if the TcpAutotuning registry entry does not exist or if it is set to a value that is not 1.
To enable the Windows Internet (WinINet) in Windows 7, follow these steps:
Click Start, type regedit in the Search programs and files box, and then press ENTER.
Locate and then right-click the registry subkey
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionInternet Settings.Point to New, and then click DWORD Value.
Type TcpAutotuning, and then press ENTER.
Right-click TcpAutotuning, and then click Modify.
In the Value data box, type 1, and then click OK.
Download canon printer driver for mac. Repeat step 2 through step 6 to add a TcpAutotuning entry with DWORD value of 1 under the following registry subkey: Northgard: the viking age edition for mac.
HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftWindowsCurrentVersionInternet SettingsExit Registry Editor.
Restart the computer.
WinINet is enabled if the TcpAutotuning registry entries are set to 1. WinINet is not enabled if the TcpAutotuning registry entries do not exist or if they are set to a value that is not 1.
Tcp Auto Tuning Windows 7
Check whether the problem is fixed. If the problem is fixed, you are finished with this article. If the problem is not fixed, you can contact support.
Issues that may occur after you enable the Receive Window Auto-Tuning feature for HTTP traffic
When the Receive Window Auto-Tuning feature is enabled for HTTP traffic, older routers, older firewalls, and older operating systems that are incompatible with the Receive Window Auto-Tuning feature may sometimes cause slow data transfer or a loss of connectivity. When this occurs, users may experience slow performance. Or, the applications may crash. These older devices do not comply with the RFC 1323 standard. Some device manufacturers provide software that works around the hardware limitations. Contact the device manufacturer to determine whether this kind of software is available.
If the incompatible devices are outside your organization, and you cannot change the devices, this issue will remain. Therefore, you may have to disable the Receive Window Auto-Tuning feature for HTTP traffic.
Disable the Receive Window Auto-Tuning feature
To disable the Receive Window Auto-Tuning feature for HTTP traffic, follow these steps:
Log on to the computer as a user who has administrative credentials.
Click Start, type
runas /user: local_computer_name administrator cmdin the Start Search box, and then press ENTER.When you are prompted for the administrator account password, type the correct password, and then press ENTER.
At the command prompt, type the following command, and then press ENTER:
Exit the Command Prompt window.
Restart the computer.
Check whether the problem is fixed. If the problem is fixed, you are finished with this article. If the problem is not fixed, you can contact support.