gtpc1m0rTransmission Control Protocol/Internet Protocol

Determining the Value for the CLAWFD Parameter

The number of file descriptor entries and CLAW send message blocks is defined using the CLAWFD parameter of the SNAKEY macro. The value of the CLAWFD parameter for a particular processor depends on the CLAWADP value you are defining for that processor and the number of file descriptors you define for each TCP/IP offload device. Increasing the CLAWFD value does not significantly raise the amount of main storage needed, so set the number of file descriptors you define for each TCP/IP offload device equal to the maximum number of socket descriptors which can be created for each TCP/IP offload device. The maximum number of socket descriptors which can be created for the IBM 3172 Model 3 Interconnect Controller is 2000. In choosing a CLAWFD value for a particular processor, use the following:

CLAWFD = Number of file descriptors × number
         of TCP/IP offload devices attached to a processor
Note:
To avoid the depletion of file descriptors when you are running your socket applications, set the number of file descriptors to the maximum value.

Example: If you plan to use three IBM 3172 Model 3 Interconnect Controllers on processor A, set the CLAWFD parameter for that processor as follows:

2000 × 3 = 6000