In IMS™ or CICS® subsystems, applications receive communication services from terminal management functions of subsystems. Thus, the IMS programmer thinks of a device as an LTERM and the CICS programmer thinks of a device as a TCTTE entry.

Many IMS and CICS applications have algorithms that derive LTERM or TCTTE names for printers by performing some hashing technique on the input LTERM or TCTTE names. If the Network Print Facility is used with Telnet, this creates problems because Telnet assigns the input LU name (and thereby the LTERM or TCTTE name) arbitrarily from a pool of LU names. If this type of algorithm is in use in your installation and you are using Telnet support, IBM® recommends that the IP-LU mapping feature of Telnet be used. This feature allows the specification of the input LU name rather than having it randomly selected from a pool. This would, in turn, permit the application to select the LU name for the printer. See the LUMAP statement described in z/OS Communications Server: IP Configuration Guide.