When VTAM activates sessions

VTAM® usually activates sessions only as needed to meet conversation requests. If the session limit is raised as a result of a CNOS negotiation, VTAM can activate sessions up to the new session limit. VTAM does not activate sessions that would exceed the current negotiated session limits.

You can force VTAM to activate sessions as soon as the session limits on a mode are negotiated by using the AUTOSES parameter. If you code the AUTOSES parameter on the APPL definition statement, VTAM activates contention-winner sessions up to the lesser of:

New minimum number of contention-winner sessions
Number of sessions specified for the AUTOSES value on the APPL definition statement
Number of sessions specified for the AUTOSES value on the APPCCMD CONTROL=OPRCNTL, QUALIFY=DEFINE macroinstruction

The AUTOSES value specifies the number of contention winner sessions VTAM will maintain. VTAM automatically reestablishs sessions when AUTOSES is specified. For example, if the minimum negotiated contention winner limit is 5 and the AUTOSES value is 4, after the CNOS negotiation for the mode, VTAM automatically activates four sessions. When a session is deactivated, VTAM automatically starts a new session.

A CNOS that lowers the minimum number of contention winners to a value less than the value of AUTOSES causes VTAM to deactivate sessions as they become free.

Care should be taken when specifying the AUTOSES value. The operator may not be able to bring down unwanted sessions. A terminate request can result in VTAM starting a new session as stated above.