LU mapping selection can become complicated because of the many
variations of mapping statements, TN3270E versus TN3270 connections,
Generic versus Specific connection requests, printer association,
and LU mappings based on application name. LU mapping is very different
between TN3270E and TN3270 and will be discussed separately. But first,
some general Mapping Rules for both TN3270E and TN3270 follow:
- If multiple LUMAP statements exist for a Client Identifier all
Specific LUMAPs are searched (TN3270E only) and then all Generic LUMAPs
are searched in the order they are listed in the profile.
- If the application is known during the LU lookup and the ALLOWAPPL
or RESTRICTAPPL-USER statement has LUs listed, then the found LU
must be in both the mapped LU group and in the application LU group.
- When an LU match is found, the search stops.
- Telnet performs database lookup for Objects based on the Client
Identifier. TN3270E connections require an Early Lookup so Telnet
can give the client an LU name during connection negotiation. In all
cases a Complete Lookup is done when the application name is known.
Telnet performs an Early Lookup and a Complete Lookup for TN3270E
connections. Telnet performs only a Complete Lookup for TN3270 and
Linemode connections.