How to use XCOM for z/OS without SNA?

Document ID : KB000052518
Last Modified Date : 14/02/2018
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Description:

Since Version r11 of XCOM for z/OS you can perform transfers and communicate with the XCOM-Server without using SNA (i.e. without running VTAM). This document explains how this is accomplished.

Solution:

When you send an XCOM transfer to the XCOM Server on the mainframe (TYPE=SCHEDULE) or execute it directly (TYPE=EXECUTE) the transfer is using an ACB, regardless if the transfer itself is using TCP/IP or SNA. You can see that an ACB was used in messages:

  XCOMM0008I XCMLS200 ACB OPENED SUCCESSFULLY
  and
  XCOMM0015I XCMLS200 ACB CLOSED SUCCESSFULLY

appearing in the Joblog. When TCP/IP is used as medium, that ACB will not be used. But if there is no ACB available, the transfer fails.

With Release r11 of XCOM for z/OS you can use new parameter SNA=NO in the Default table to tell XCOM to not use any ACB for transfers. To accomplish this you need to perform these two steps:

  1. Add parameters SNA=NO to the Default Table you are using.
  2. Assemble and Link that table to make the change become effective.

When performing a direct transfer using TYPE=EXECUTE there is nothing more to do, simply specify the IP-address or name of the recipient system.

When doing a TYPE=SCHEDULE transfer via the XCOM-Server you need to specify the location of the Server using parameters STCIP and STCPORT in the PARM-Statement of the Transfer-Job. If you omit that, the result will be message:

XCOMM0817E STCIP= PARAMETER MISSING - CANNOT CONNECT TO SERVER

and the Job fails.

The IP-Address and the Port the XCOM-Server is listening on are documented in the Job-Log of the Server:

XCOMM0788I XCOM TCP/IP LISTENER ACTIVE ON PORT nnnnn, STACK TCPIP
XCOMM0819I TCP/IP FUNCTION GETHOSTID RETURNS ADDRESS nnn.nnn.nnn.nnn

The PARM-statement looks like this:

//    PARM=('TYPE=SCHEDULE',
//    'DFLTAB=<name_of_Default_table>',
//    'STCIP=nnn.nnn.nnn.nnn',
//    'STCPORT=nnnnn')