SNAX/XF LU Network Services Manual

LUNS Configuration Tables
Introduction to LUNS
1–4 097841 Tandem Computers Incorporated
Starting TACL Processes
With the Creator Process
TACL processes are started by the Tandem Creator process. When a user wants to
start a TACL process, the Creator process receives a request to establish a session from
LUNS, creates the TACL process, and informs the TACL process of the terminal name.
Starting Pathway
Processes With the Creator
Process
Pathway applications also interface to LUNS by means of the Tandem Creator process.
When the user logs on to the Pathway application, the Tandem Creator process
receives a request from LUNS and establishes communications with Pathway, passing
the terminal name and the name of the Pathway program to the relevant Pathway
monitor (PATHMON) process. The PATHMON then instructs the terminal control
process (TCP) to open the terminal on behalf of the Pathway program.
Note that you need not define Pathway programs to LUNS through an ADD APPL
command. LUNS knows how to route the logons because of a field in an ESS table.
This field contains the names of a PATHMON and a destination Pathway program.
Note At any given time, the Creator process can establish a combined total of 400 TACL and Pathway sessions
running C-series system software, 2000 sessions when running the ITI and CRT protocols on D-series
system software, or 1000 sessions when running the SNALU protocol on D-series system software.
LUNS Configuration
Tables
To process character-coded commands and INIT-SELF requests, LUNS must use
information derived from the following configuration tables:
An Enhanced System Services (ESS) table
The Session Establishment (SET) table
Using SNAXUTL, systems programmers design and create these tables, tailoring table
entries to the needs of their particular networks. Such a task requires an
understanding of what these tables are and how they aid in establishing LU-LU
sessions.
Another aspect of establishing LU-LU sessions is that of the PLU and SLU agreeing on
“communications rules.” LUNS allows these “communications rules” to be passed
from the PLU to the SLU through session parameters sent in a BIND. Through
SNAXUTL, LUNS allows users to build BIND entries and place them in BIND tables
that are later selected for use at session establishment.
Notation Used for
Configuration Tables
The following figure illustrates the conventions used in this manual to depict
configuration tables and the various records within. Note that theses figures provide a
logical representation of the information; however, the actual records are not stored in
exactly this way.