Increasing Throughput & Avoiding Socket Errors Going to XCOM for Windows

Products

• XCOM Data Transport
• XCOM Data Transport - Windows
• XCOM Data Transport - Linux PC
• XCOM Data Transport - z/OS

Issue/Introduction

How to avoid Socket error messages when sending to XCOM for Windows.  How to configure.  Suggested values 

Environment

Release: XCOM for Windows
Component: xcpcnt

Cause

Increasing the Maximum Clients parameter on Windows may increase the performance when transferring many simultaneous files to the Windows.

Resolution

The Maximum Clients Range value controls the maximum number of incoming (remote) transfers which can be handled by the CA-XCOM Data Transport TCP/IP listener function (caxcgsvr.exe) at one time. The CA-XCOM TCP/IP listener function handles incoming transfers until an CA-XCOM transaction program (xcomtcp.exe) starts and takes control of the transfer. XCOM allocates a 32K block of storage for each Maximum Clients buffer.

The default for Maximum Clients is 16. In general, Maximum Clients should be set to a number slightly more than half the number of simultaneous transfers that are incoming to the NT box. The Maximum Clients parameter does not indicate the maximum number of simultaneous transfers that may be active to the Windows, but specifies a buffering parameter. It allows the TCP/IP listener on NT to buffer transfers coming in and holds them for the XCOM transaction program until it can process the transfer.

For example:
XCOM for z/OS is sending 40 simultaneous transfers to Windows. The Maximum Clients parameter should be set to a value more than half, such as 25.

If the number of incoming (remote) transfers which are starting at one time exceeds the Maximum Clients Range value, then the listener waits while transfers in progress run through to completion. The listener will continue once one of the previously started transaction programs has been initialized.

Instructions:

How to set the Maximum Clients Parameter:

On Windows, in the XCOM GUI, select:

Global Parameters tab
TCP/IP section
Change Maximum Clients to the desired value and click apply.

Stop and start xcomd