Reestablishing the session

The failed session can be restarted by either half-session partner.

When it is restarted, the relationship of the half sessions is the same as when the session failed; that is, the former primary half session continues to be primary and the former secondary half session to be secondary. Both IMS and CICS® remember this orientation by logging the session qualifier pair (SQP) used to initiate the session with an indicator of the session polarity.

The CICS master terminal operator can reinitiate the session using the command:

CEMT SET TERMINAL (tttt) ACQUIRED

where tttt is the TERMIDNT of the CICS session as defined in the terminal control table. CICS then brings up the session, maintaining the session polarity that has been fixed by CICS system definition parameters. If the session is being initiated by an authorized IMS terminal operator's issuing the /OPNDST command, that command must specify the same subpool name (IMS local session qualifier name) and session ID (CICS local session qualifier name) that was allocated to the session at the point of failure. These are available to the operator as necessary using an IMS /DISPLAY command. IMS automatically reestablishes the session, while maintaining the same session polarity as was in effect at session failure.

If the session is being restarted with IMS in cold-start mode, and if CICS is defined to be the primary half session, CICS must initiate the restart.

When the session is reestablished, IMS attempts to reset the data flow control bracket state to its status at the last sync point before session failure. CICS allows the session to be reestablished as between-brackets or as in-brackets with IMS in SEND state.