Ref: 99980060
Title: Application Note-Installing a Prime Host on the CS/1-X/25
Date: 2/1/86

Copyright 3Com Corporation, 1991.  All rights reserved.

The Bridge CS/1-X.25 is used to front-end a host with an X.25
interface such as the Prime host.  In order to install a Prime
host to the CS/1-X.25, the system generation should be executed
on the CS/1-X.25.  On the Prime host, the following controllers
should be installed:

.br;-   ICS/1
.br;-   ICS/2
.br;-   5602 or 5604 MDLC controller

The following sections describe the setting of the CS/1-X.25's
system generation program and the Prime host's X.25 parameters.

.h1;Running the System Generation Program on the CS/1-X.25

The system generation program (sysgen) is a program embedded in
the software of the CS/1-X.25.  All CS/1-X.25 parameters can be
set via this program.  In order for the CS/1-X.25 to perform
properly, the following X.25 parameters should be set:

-   DCE.  Since the CS/1-X.25 is connected directly to the host,
    this device should be set to DCE.  The CS/1-X.25 default
    setting is DCE.

-   X.25 level-3 packet size has a default setting of 128 bytes.
    The packet size can be increased up to 512 bytes.  Due to the
    memory limitation, the number of virtual ports should be
    decreased in proportion to the increase in packet size.  For
    example, if you increase the packet size to 256 bytes, the
    number of vitual ports should be reduced to 24.  If you
    increase the packet size to 512 bytes, the number of virtual
    ports should be reduced to 12.

-   X.25 level-3 window size has a default setting of 2.  The
    window size can be increased up to 7.  When increasing the
    window size, the number of virtual ports should be decreased.

-   Number of logical channels has a default setting of 20; this
    number can be increased up to 48.

-   Configure the X.25 address for the appropriate line on the CS/
    1-X.25.

.h1;Configuring a Prime Host's X.25 Parameter

The Prime computer has different commands depending on the
revision of the Primos operating system.  If the Prime is running
Revision 19 or earlier, the command is NETCFG.  If the Primos
operating systemis Revision 20 or later, the command is CONFIG-
NET.

The NETCFG or CONFIG-NET command should be executed in a
different directory to create the necessary file.  After the file
is created, it should be copied to CMDNCO.  Do not initiate the
file under the CMDNCO directory.  If the file is initiated under
the CMDNCO directory, it will overwrite an existing file.

After the NETCFG or CONFIG-NET command has been entered, there
will be a menu display:  The following example displays the menu
and the appropriate answers to configure the Prime host:

    QUESTION                    ANSWER

    Create, modify, delete      Create
    Number of nodes             None
    Nodes on this ring          None
    Nodes on another ring       None
    Your public data network    <Enter the PDN Interface>
    Host connected to:          <Enter the name of yoru host>
    PDN address                 <Enter the X.25 address>
    Line # connecting to        0
    Protocol (Lap or LapB)      LAPB
    Framing (HDLC, Bisync...)   HDLC
    Number of virtual circuits  20
    Window size                 2
    Packet size                 128


