A group of applications can be given a common or generic name. VTAM® uses this generic name, known as a USERVAR, to associate a logon request with the currently active member of this group. This capability can be used for workload balancing and preparing for the planned takedown of a host. USERVAR values can be managed by the user and by VTAM.

For example, assume that the USERVAR, IMS™, has been defined, and that there are two IMS application programs: IMS1 and IMS2. The generic name (USERVAR) can be assigned the value of either IMS1 or IMS2, based on which system is active. If the USERVAR for the IMS application programs is set to IMS1, for instance, then any session requested with IMS is routed to IMS1. If IMS is set to IMS2, then new sessions are routed to IMS2. Therefore, if the workload going to IMS1 is very heavy, the IMS USERVAR can be set to IMS2 and subsequent sessions are routed to IMS2.