Defining dynamic terminals for ISC TCP/IP sessions

When the IMS Extended Terminal Option (ETO) is enabled, you can use ETO logon descriptors to enable the dynamic creation of terminals for ISC TCP/IP LU 6.1 sessions.

At least one logon descriptor must be defined to enable IMS to create ISC TCP/IP terminals dynamically. At least one logon descriptor must be defined for each IMS Connect instance that supports dynamically defined ISC TCP/IP nodes.

Logon descriptors are stored in two members in the IMS.PROCLIB data set:
DFSDSCMx
For the default logon descriptors that are created by IMS during a cold start.
DFSDSCTy
For the logon descriptors that are created by your installation.
Recommendation: When you create your own logon descriptors, to preserve them across stage-1 system definition processing, store your logon descriptors in the DFSDSCTy PROCLIB member.

You can add to or modify the descriptors in the DFSDSCMx member. However, during the processing of a stage-1 system definition, IMS deletes the contents of the DFSDSCMx member and re-creates all of the default descriptors.

IMS creates a default logon descriptor for ISC TCP/IP terminals named DFSTCP. To use the default ISC TCP/IP descriptor for sessions started in IMS, you must specify it explicitly by using the LOGOND keyword in the /OPNDST command. ISC TCP/IP sessions that are initiated from CICS® can use the default logon descriptor, but only when no other logon descriptor matches the node name specified by CICS.

Procedure

  1. To create a logon descriptor for an ISC TCP/IP terminal, code an ETO logon descriptor that specifies UNITYPE=ISCTCPIP and LCLICON=lcl_imsconnect_name.
    The IMS Connect instance that is specified on the LCLICON keyword provides the TCP/IP support, including the network address and port of the CICS subsystem.
  2. Optional: define an ETO user descriptor.
For example:
L ISCTCP1  UNITYPE=ISCTCPIP LCLICON=HWS1     
L ISCTCP2  UNITYPE=ISCTCPIP LCLICON=HWS1     
L ISCTCP3  UNITYPE=ISCTCPIP LCLICON=HWS1     
L ISCTCP4  UNITYPE=ISCTCPIP LCLICON=HWS1     
L ISCTCP5  UNITYPE=ISCTCPIP LCLICON=HWS1     
L TERMA    UNITYPE=3270 UNIT=3284            
L DFS327P  UNITYPE=3270 UNIT=3284            
U DFSUSER  OPTIONS=(TRANRESP)