SNAX/APC Configuration and Management Manual

Planning for SNAX/APC
SNAX/APC Configuration and Management Manual—138787
2-2
Static Structures
LUs (represented by half-session processes), and active conversations (represented by
conversation resources).
Tandem has extended the capabilities of the data structures within the SNAX/APC
implementation of APPC. Partner LUs and partner modes may optionally become
dynamic structures created and configured on demand during a session, whereas the
standard 6.2 implementation requires that they be configured before the sessions begin.
Static Structures
Figure 2-1 shows the data structures that represent LU-accessed network resources. You
should know the particular names or values for these resources before you can configure
SNAX/APC.
The local LU information, shown at the top of the figure, describes the local LU. This
information includes the LU’s fully qualified network name and the set of optional
functions, for example parallel sessions, that the LU supports. You will have to provide
this information for each local LU.
TPGM 1, 2, and so on, represent the transaction programs that may be attached to the
local LU. You should know the unique TP name for each program.
Partner LU 1, 2, and so on represent the remote LUs, potential session partners to the
local LU. This structure includes the remote TP’s local and network-qualified names. It
also includes the LU’s set of optional capabilities, such as parallel sessions and security.
In a standard implementation of APPC you should have all this information before you
configure your system. With SNAX/APC, this is now optional. If you wish to pre-
define the partner LUs, you should use the Subsystem Control Facility (SCF). If you do
not pre-define the partner LUs and partner modes, SNAX/APC will add those data
structures (objects in SCF terminology) as required. There are advantages and
disadvantages to either decision. For example, a pre-defined LU session will start
slightly faster because there is less work to do, and ensures that you can only be
contacted by LUs you have defined. On the other hand, dynamic configuration is easier
and enables a more flexible network configuration.
The partner LU also contains a list of mode descriptions. A mode is a set of session
characteristics that a group of sessions share for a particular partner LU. These
characteristics typically correspond to different requirements for cost and performance.
Modes are defined by the control operator as a selection of path control network and LU
session-processing parameters.
A combination of partner LU and mode is called an (LU,mode) pair. The pair is
represented by the PTNR-MODE object in SNAX/APC. The (LU,mode) pair are also
optionally static or dynamic in SNAX/APC configurations.