VTAM® allows, at
most, two LU entries for a given partner LU. For example, if an application
attempts to initiate a session with a partner LU using the partner's
generic resource name, the partner can return its real network name
on the BIND response. VTAM manages
the LU entries so that the name supplied by the application can be
associated with the name returned by the partner. Only one set of
mode entries is maintained for the partner, eliminating conflicting
information.
There can be five types of LU entries in the LU-mode table.
- SUPPLIED_NAME Entry
- This is an LU entry that is created using the LU name specified on an APPCCMD macroinstruction
or the corresponding operator command. This type of entry holds any
mode entries for the partner LU. This type of entry may or may not
have an associated entry.
- RCVD_NAME Entry
- This is
an LU entry that is created due to a session initiation request from
the partner LU. This type of entry holds any mode entries for the
partner LU. It may subsequently be changed to a SUPPLIED_NAME entry
or a VARIANT_NAME entry. This type of entry does not have an associated
entry.
- VARIANT_NAME Entry
- This
is an LU entry that is created when the LUNAME in the BIND response
is different than that specified on the APPCCMD or operator command
which caused the session request. This type of entry has no mode entries
and contains only a limited amount of relevant information. This type
of entry is always associated with a SUPPLIED_NAME entry, which contains
the complete set of LU information and all related mode entries for
the partner LU.
- UNUSABLE_NAME Entry
- This
is an LU entry that has been marked unusable due to inappropriate
name translations or conflicting LU definitions in the network. Any
attempt to use this LU name is rejected as an error. This type of
entry has no mode entries. An UNUSABLE entry contains a limited amount
of information for problem determination purposes, and remains in
the LU-Mode table until the table is deleted when the application
closes its ACB or an operator deletes the entry on a MODIFY DEFINE
command.
- DISASSOC_NAME Entry
- This
is an LU entry that was previously a VARIANT_NAME entry but is no
longer associated with any other entry. It remains in the table but
is changed to another entry type if its name is referenced in session
startup. This type of entry has no mode entries.