How defined negotiation limits are set

When session limits are added to the LU-mode table, the defined negotiation limits are set as follows:

When the application program sets the values
If the application program issued the APPCCMD CONTROL=OPRCNTL, QUALIFY=DEFINE macroinstruction to add negotiated limits to the LU-mode table, VTAM® reads the defined negotiation limits out of the DEFINE/DISPLAY control block (ISTSLD structure) that was specified on the macroinstruction. See Defining negotiation limits and displaying session limits for more information on how to issue a DEFINE macroinstruction.
When VTAM sets the values
If VTAM is adding an LU-mode table entry (not modifying an entry) because a CNOS request is being processed on the logon mode (on either the target or source side), VTAM adds the LU-mode table entry and sets the defined negotiation values using the corresponding parameters on the APPL definition statement:
Parameter

Description

DSESLIM

Sets the defined overall session limit in the LU-mode table mode entry. If this parameter is not coded on the APPL definition statement, VTAM uses the default value of 2.

DMINWNL

Sets the defined number of guaranteed contention-winner sessions for the local LU. If this parameter is not coded on the APPL definition statement, VTAM uses the default value of 1.

DMINWNR

Sets the defined number of guaranteed contention-winner sessions for the remote LU. If this parameter is not coded on the APPL definition statement, VTAM uses the default value of 1.

For more information on the default values and on coding the APPL definition statement, refer to the z/OS Communications Server: SNA Resource Definition Reference.