TCP_NODELAY Variable Description

When a FLEXnet licensing session is established, TCP/IP sends data between the server and client by using packets. By default, the TCP/IP processing kernel delays small packet transmissions to gain an efficiency advantage. The advantage occurs by using a buffer to coalesce many small packets before sending them across the network.

The delays can result in artificially high latency times for the small packets that are related to most FLEXnet licensing operations.

Set the TCP_NODELAY system setting (as a FLEXnet license server environment variable) to overcome the delay behavior and to reduce the licensing wait period. Using this setting causes data packets to be sent through the network more frequently. As a result, there is less of a delay in the licensing process due to TCP/IP operations.

However, network traffic can increase as a result of smaller and more frequent licensing-related packet transmissions.

Setting the TCP_NODELAY Variable

The user can set the variable on or off on both Windows and Linux. On Windows, you will do that in the environment variable menu.

TCP_NODELAY Variable on Windows.

On Linux, you can use the following commands to enable or disable the variable.

export TCP_NODELAY=YES            (to enable the variable)
unset TCP_NODELAY                 (to disable the variable)