Managing LU 6.2 sessions with operator commands

Session characteristics, such as session limits, LU capability, and LU responsibilities, must be managed for every conversation involving an LU 6.2 application program. These characteristics can be controlled by the application program and through operator commands.

Operator commands manage conversation resources by establishing or modifying:

New session limits between an application and partner LU (MODIFY CNOS).
Session limit values VTAM® uses to negotiate CNOS requests initiated by a partner LU for a specific application (MODIFY DEFINE). These values are stored in the logon mode table.

You can establish session limits using the MODIFY CNOS operator command. After session limits are established, actual sessions can be started.

Session limits must also be established for a mode name before conversations that use that mode can be allocated. When a request for a session is made, the requested session limits can be accepted by the partner LU or the session limits can be changed to new values. The process for accepting or changing proposed session limits is called negotiation. Logon mode table values are used in session limits negotiation. Negotiation is handled for the application program by the MODIFY DEFINE operator command. For more information about session negotiation, see the z/OS Communications Server: SNA Programmer's LU 6.2 Guide.