TOPIC -----------------------------------------
This article discusses APPC support in particular versions of VTAM and
NCP.
DISCUSSION -----------------------------------------
Native PU 2.1 support is provided in VTAM Version 3 Release 2, NCP Version
4 Release 3, and NCP Version 5 Release 2.
One can, however, establish APPC connectivity under earlier releases of
both products using a PU type 2 definition with many restrictions on the
types of configurations supported.
These restrictions are:
1) Using a PU type 2 definition, the APPC node is relegated to the role of
a SECONDARY logical unit. The APPC node defined as a PU type 2 CANNOT
be a primary or negotiate roles.
2) The APPC node defined with a PU type 2 definition can have only ONE
session with an application in the same subarea network. Parallel
sessions and multiple sessions are NOT supported with a PU type 2
definition.
Therefore, you can run a MacAPPC node defined as a PU type 2 with earlier
releases of VTAM and NCP with SINGLE SESSION, SECONDARY logical unit
support only.
Please note that this restriction is NOT unique to MacAPPC only. All PU
type 2.1 products (including System 3X and the IBM PC) share the same
restrictions on sessions and logical unit roles in the VTAM/NCP
environment.