MTU is larger than the FastSendDatagramThreshold

When you execute Uhd_usrp_probe.exe, you are prompted with "MTU is larger than the FastSendDatagramThreshold". Here's how to fix it:

Problem

You could see a message similar to the following on Windows machines when using the-the-support package for USRP Radio Rx or Tx System objects or blocks:

The MTU (1472) is larger than the FastSendDatagramThreshold (1024)!

This would negatively affect the transmit performance.

See the transport application notes for more detail.

Possible Solution

The Ettus Web site has a document,uhd-transport application Notes (broken Links), which describes this problem. See the MicroSoft Web site:optimizing Windows Media Services for Appendix E:registry Key for information on increasing th is setting. After you has perused these documents,follow the instructions in this section to apply the change.

　　Warning incorrectly editing the registry may serverely damage your system. Before making changes to the Registry,you shuold back up any valued data on your computer.

To increase the fastsenddatagramthreshold,follow these steps:

1.Click Windows Start, Enter regedit in Search programs and files

2.using the left side navigation Windows,go to hkey_local_machine\system\currentcontrolset\services\afd\parameters\.

3.Right click on Parameters and Select New->dword (32-bit) Value.

4.Enter FastSendDatagramThreshold as the name.

5.Right click on fashsenddatagramthreshold value and select Modify.

6.Enter for Value data. Select Decimal as Base value.

7.Click OK. FastSendDatagramThreshold should now has the following settings:

8.Close the Registry Editor. A system reboot is recommended after the registry key change.

Ps:file:///c:/matlab/supportpackages/r2013a/sdru/help/gs/btojzt3.html

MTU is larger than the FastSendDatagramThreshold