ETO and LU 6.1 (ISC) terminals

For LU 6.1 (ISC) terminals, IMS supports parallel sessions to the same node name. In this case, a separate structure is built for each session. However, each session and its associated structure operate independently, as a separate terminal.

ISC supports an SNA-defined user-data area within the BIND. When establishing a session for ISC, each half-session partner is identified through an appropriate session qualifier that is included as user data with the logon. These two qualifiers cannot be specified using the DFSLGNX0 exit routine. One belongs to each half session. IMS uses the session qualifier of the current half session as a user structure. This user structure is used to allocate an associated set of LTERM queues and to automatically provide a RACF® signon, if required. The other half-session qualifier is saved with the IMS user structure. Both qualifiers are used for session-restart requests and SNA STSN message resynchronization after session failures.

Restriction: The SNA-predefined format for user data does not support some of the parameters and options of the non-ISC end-user format:
  • The RACF password and group name are not supported. IMS supports RACF signon for ISC with PASSCHK=NO during user structure allocation as part of session initiation.
  • The LOGOND and USERD are not supported. IMS uses defaults, unless specified on the Logon and Signon exit routines.
  • When autologon is generated for ISC terminals, the AUTLDESC keyword in the user descriptor is ignored, and the LOGOND keyword in the user data is omitted.