The LANMAXOUT parameter

The Maximum outstanding data frames (LANMAXOUT) parameter of your Systems Network Architecture (SNA) controller description specifies how many frames your system sends before waiting to receive an acknowledgment.

The LANMAXOUT parameter is highly sensitive to the remote station's speed to copy and acknowledge frames (speed is based on buffering capabilities and processing resource).

Performance problems:

For optimal performance, you must choose appropriate values for the LANMAXOUT and LANACKFRQ parameters on both the sending and receiving stations.

These variables affect which LANMAXOUT and LANACKFRQ values provide the best performance:

• The characteristics of the application.
• The amount of data sent.
• The rate that the application can present and accept data.
• The data blocking characteristics.
• The LAN adapter type.
• The processing unit model.
• The utilization of the line, the adapter, and the processing unit.
• The internal buffering capabilities.

In most environments, the default value (*CALC) for LANACKFRQ and LANMAXOUT offer the best performance. However, for some environments, changing the values can improve performance significantly.

If you want to change LANMAXOUT, see Change timing parameters.