IBM CL/SuperSession V2.1 TN3270 Basic Client Support

Content

TN3270-Client Implementation

A TN3270 client facilitates communication with a TELNET Server by using established protocol. An example of a TN3270 client is IBM’s Personal Communications. With Personal Communications, a user can connect to a host application by specifying the target TELNET server’s IP address and Port number.

In most cases, a client targets the TELNET server of the OS. For example, you cannot connect directly to TSO but you can connect to the TELNET server (a part of z/OS Communications Server) on the LPAR on which TSO is running and then connect to TSO.

With PTF UA95184 (and follow-up PTFs), IBM CL/SuperSession supports a basic connection to a target TELNET server over a TCP/IP network.  This provides a connection from IBM CL/SuperSession to servers beyond the Sysplex or Enterprise Extender boundaries to, for instance, a target z/VM stack or a z/OS IBM Telnet server to then connect to TSO or CICS.

This functionality is supplied “as is.” IBM Corporation does not provide any warranties, express or implied, including, but not limited to the implied warranties of merchantability and fitness for any particular purpose.

Installation and configuration

Basic TN3270 Client support is introduced in the V210 maintenance stream.

The way to activate TN3270 client support is to add to your RLSCMDS(KLSSTART) the following:

NTD KLSSOPTS 'KLSOPTTN APPLID | NODE'

… where applid is an available APPLID that IBM CL/SuperSession can use to define as the TN3270 hostgate. A special keyword, NODE, is also available to make configuration more “automatic.” When NODE is specified (for example, NTD KLSSOPTS 'KLSOPTTN NODE') IBM CL/SuperSession will locate the APPLID that the environment has configured for the deprecated Engine Operator and use that after first deactivating the Engine Operator, in most cases this is the APPLID ssterm0.

At startup, a confirmation is echo’ed in the TLVLOG similar to:

(TN3270 Gateway ACB):         NODE

Use TN3270 Basic Client Support

Adding a TN3270-type session is similar to adding access to any other application. You can either create an APPLDEF or add the session by using the CL/SuperSession profile administration interface and/or end-user menu customizations.

APPLDEF __TESTIP -     

DEST=SSTERM0 -               

USERDATA='//4.1.1.1:23' -    

DESC='TELNET CLIENT APPLDEF' -

POOL(TN3270CL) -             

GROUP=9999                   

Of note from the example are two items:

DEST must specify the TN3270 gateway APPL. This ensures the application displays as “available” on the user’s main menu though other security issues still apply. For instance, if the site uses external security to determine which applications a user can access, they must be granted access to the TN3270 gateway APPL.

For TN3270 sessions, USERDATA contains the target IP address and port.

“A”dd new session

“PF4” on DEST= to prompt session type

Fill-in new data and press ENTER

“M” session to verify and consider additional options:

ENTER to save;

“S”tart session

Away you go…

Current limitations

Error handling is currently limited to function. Some application/data errors may result in unpredictable results. Please report any hangs or INCORROUT. After first re-creating with full tracing enabled.

Because not all application errors have been accounted for, some clean-up cannot be completed and may result in orphaned storage. To firm this up is an ongoing effort. Please report any hangs or INCORROUT. After first recreating with full tracing enabled.

Monitoring and Debugging

TN3270 trace options are set using the KLSSOPTS dialog meaning they can be set either at startup by updating the KLSSTART command member, or set/reset dynamically using the MVS modify command.

The format in either case is:

NTD KLSSOPTS 'KLSOPTCK TRACE(U=*,ALL)’

This documentation will be provided in a future update to the CL/SuperSession Configuration Guide.

Visit the CL/SuperSession home page for more product information.

Visit the CL/SuperSession Maintenance page for the latest available PTF's.