Disabling unused TCP global settings in Windows Server 2008 and later

Avoid performance problems by disabling TCP global settings that are available in Microsoft™ Windows™ Server 2008 and later (including Windows Server 2012), but are not used by IBM® Sametime® 9.

About this task

If you will not install the Sametime Community Server on Windows Server 2008 or later, skip this task.

This task modifies the registry on your Windows 2008 server and disables some TCP global settings. You will back up the affected part of the registry before making the updates so that you can undo the changes if needed.

Attention: Using the netsh command to modify global TCP parameters might change other parameters to incorrect settings; for more information, see the Microsoft Support note 967224.

Procedure

Verify that the unwanted TCP global settings are enabled:
1. Open a command prompt.
2. Run the following command: netsh int tcp show global
3. Check the status of the following 4 settings:
  - Chimney Offload
    The status should be disabled
  - Receive-Side Scaling
    The status should be disabled
  - Receive Window Auto-Tuning Level
    The status should be disabled
  - Add-on Congestion Control Provider
    The status should be none
  If all of the settings display the appropriate status, skip the rest of this task and proceed with the IBM Domino® installation as described in the next topic.
  If any of the settings displays an incorrect status, disable it as explained in the following steps.
Back up the server's registry:
Modifying TCP global settings results in a change to the Windows registry. Back up the current version of the registry before making any changes.
1. Open the Registry Editor by clicking Start > Run, typing regedit, and clicking OK.
2. In the navigation tree, expand HKEY_LOCAL_MACHINE\SYSTEM > CurrentControlSet > Services > Tcpip > Parameters.
  This is the part of the registry that will be affected by the changes to the TCP global settings; you can back up just this section, or any higher level that includes this section.
3. Click File > Export.
4. In the Export Registry File dialog box, select a location to store the file that will contain the backed up settings, type a name for the file (leave the file type set to .reg), and click OK.
5. Close the Registry Editor.
Disable TCP global settings:
1. Open a command prompt.
2. Run the appropriate commands from the following list to disable settings:
  - Chimney Offload
```
netsh int tcp set global chimney=disabled
```
  - Receive-Side Scaling
```
netsh int tcp set global rss=disabled
```
  - Receive Window Auto-Tuning Level
```
netsh int tcp set global autotuninglevel=disabled
```
  - Add-on Congestion Control Provider
```
netsh int tcp set global congestionprovider=none
```
3. Run the netsh int tcp show global command again to verify that all 4 settings are now disabled.
4. Close the command prompt
Restart the server.