Plan your z/OS TCP/IP environment

To get the best throughput through your network, we must use TCP/IP send and receive buffers with a size of 64 KB, or greater. With this size, the system optimizes its buffer sizes.

See What is Dynamic Right Sizing for High Latency Networks? for more information.

We can check the system buffer size by using the following Netstat command, for example:

TSO NETSTAT ALL (CLIENT csq1CHIN

The results display much information, including the following two values:

ReceiveBufferSize: 0000065536
SendBufferSize: 0000065536

65536 is 64 KB. If your buffer sizes are less than 65536, we must work with your network team to increase the TCPSENDBFRSIZE and TCPRCVBUFRSIZE values in the PROFILE DDName in the TCPIP procedure. For example, you might use the following command:

TCPCONFIG TCPSENDBFRSZE 65536 TCPRCVBUFRSIZE 65536

If we are unable to change the system-wide TCPSENDBFRSIZE or TCPRCVBUFRSIZE settings, contact the IBM Software Support center.

Parent topic: Plan your channel initiator