Increasing incoming simultaneous TCP/IP transfer limit on XCOM for AS/400

Products

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

Issue/Introduction

How can the throughput of incoming simultaneous TCP/IP transfers to XCOM Data Transport on AS/400 i5/OS be increased?

Environment

XCOM™ Data Transport® for AS/400 i5/OS

Resolution

There are two parameters that can be specified when issuing the command to start the XCOM TCP/IP server. The start command used will be one of the following:  

STRXCTCP (start TCP/IP IPv4 server)
STRXCTCPS (start secure socket TCP/IP IPv4 server)
STRXCTCP6 (start TCP/IP IPv6 server)
STRXCTCP6S (start secure socket TCP/IP IPv6 server)

MAXCLIENTS    Default 2    Range 1- 50
This is the number of concurrent TCP/IP transfers than can be processed. This value specifies the number of Agents that XCOM will start.

MAXBACKLOG    Default 5    Range 1- 512
This is the TCP/IP request backlog parameter. It indicates the maximum number of TCP/IP transfers that can be queued up waiting to be processed. Any additional transfers after this number will be rejected. Set this parameter equal to the maximum number of transfers that can reach the AS/400 simultaneously.

Engineering advises:

1. increase the MAXCLIENTS to the maximum number of concurrent transfers that need to be run.
2. Set MAXBACKLOG to MAXCLIENTS + 3. 

The amount of storage initially required is 1K times MAXBACKLOG. In addition, if transfers arrive simultaneously, then buffers will be allocated by TCPIP for the transfers that are waiting.

Additional Information

XCOM™ Data Transport® for AS/400 11.0 > Using > Processing Options > Remote TCP/IP Transfers