TCP Stack Affinity For XCOM Data Transport For z/OS

Products

• XCOM Data Transport
• XCOM Data Transport - z/OS

Issue/Introduction

As a general rule, both incoming and outgoing transfers from XCOM for z/OS will default to the IP stack specified in the SYS1.PARMLIB(BPXPRMxx) as the primary stack. If that stack is busy,  XCOM will use the secondary stack if one is available.

 

 

 

Environment

Release:  XCOM Data Transport for z/OS 12.0

xcmvs

Resolution

Configuring Stack Affinity

SERVADDR

• Use the SERVADDR= parameter to specify a single IP address from which the z/OS CA XCOM server will accept incoming requests. If the SERVADDR parameter is specified XCOM will use only that stack for incoming transfers. For example, in sites with multiple stacks, only the ipaddress (stack) specified in SERVADDR will accept incoming requests.
• When sending from a remote partner you must specify the ipaddress (stack) specify this SERVADDR address. This parameter defaults to none.

TCPSTACK

• Use the TCPSTACK= parameter to specify the job name or started task name of the TCP/IP stack that will be used. Otherwise this parameter defaults to none. For both incoming and outgoing transfers XCOM will default to the IP stack specified in the SYS1.PARMLIB as the primary stack. If that stack is busy, it will use the secondary stack if one is available.
•  If the TCPSTACK parameter is specified, XCOM will use that stack for both incoming and outgoing transfers.

Determining what Stack is in Use

For all platforms, you may determine what stack is used by looking at the local XCOMLOG on the server. For MVS the following message will be issued in the XCOMLOG:

XCOMM0793I TCP/IP REMOTE CONNECTION ESTABLISHED FROM IP=

The IP address above shows the remote system outgoing stack address.