Configuring IMS Multiple Sign-on Support

Multiple sign-on support is implemented using the following Enterprise Server environment variables:

Enables or disables functionality that allows a single user to sign on to multiple LUs simultaneously.


Disables multiple sign-on functionality.
Enables multiple sign-on functionality.

When ES_IMS_SINGLE is set to N, and a user attempts to sign on to an LU using a sign-on that is currently active at another LU, IMS Transaction Manager (TM) assigns a temporary LTERM to the user and LU using a name constructed from the ES_IMS_LTERM_PREFIX setting followed by a numerical value totalling eight characters (see the IMS_LTERM_PREFIX entry in this topic for details). The temporary LTERM is the destination for the user and LU irrespective of activity at other LUs controlled by the user. When a user disconnects from an LU that is served by a temporary LTERM, the LTERM is returned to the temporary pool for reuse.

Also when ES_IMS_SINGLE is set to N, the execution of /dis USER all returns a sub-list for each user that shows all active connections. These connections persist throughout a session, and are dynamically recreated during a warm start.



Note: No KEYPOINT activity is associated with the use of ES_IMS_SINGLE.
Specify a one- to four-character LTERM prefix alternative to the default (OTMA) to use when the ES_IMS_SINGLE environment variable is set to N. Use of an alternative prefix to OTMA enables you to exercise control over name conflicts.




Use up to four characters of your choice. Enterprise Server pads the value specified with numeric digits up to eight characters, enabling the LTERM pool to be expanded from 9999 up to 999999. The pool size is dictated by the number of characters used in the specified prefix. For example, the LTERM pool size for a four-character prefix is 9999; for a three-character prefix is 99999; and so on.



Note: The default setting of this environment variable suggests that the LTERMS apply only to OTMA clients; however, this is not the case. LTERMS can also be applied to second and subsequent 3270 user connections.