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Software Communications

ND 10405 COSMOS X.29 PAD

+-------------------------+
|       ND SYSTEM         |
|                         |
|       X.29              |
|       P A D             |
|                         |
|      (IS) XMSG          |
|                         |
|   +-----------------+   |
|   |  Packet level   |   |
|   +-----------------+   |
|   |   Link level    |   |
|   +-----------------+   |
|   | Physical level  |   |
|   +-----------------+   |
|                         |
|       X.25              |
|     NETWORK             |
+-------------------------+

      X.25

+------------------------+
|     ND SYSTEM          |
|         OR             |
|    OTHER SYSTEM        |
+------------------------+

Introduction

COSMOS is Norsk Data's distributed communications environment. It provides communication and application services to augment the services offered by SINTRAN III to its users.

Three protocols, X.3, X.28 and X.29 (Triple-X), define how an asynchronous terminal connected to a PAD (Packet Assembly Disassembly) can communicate with a host over an X.25 packet switched network. The PAD will pack the characters coming from the terminal and send them as packets across the X.25 network. Packets coming from the host will be unpacked and sent as characters to the terminal. The PTT will offer this PAD service. This means that it is possible to connect an asynchronous terminal to one of these PADs via a telephone line. However, many manufacturers (like Norsk Data) offer the same service via their computers. Terminals connected to an ND computer can run a sub-system called a PAD program that will do exactly the same as the PTT PAD service, but it will be much easier to use.

The host receives the packets of packed characters from a PAD needs a system that can unpack received packets and send them as asynchronous terminal characters to the operating system, and pack and send the characters received in response. For more information about this product, see the ND 10578 COSMOS X.29 SERVER data sheet.

The COSMOS X.29 PAD allows a terminal connected to an ND system access to any other system that has implemented the server part of the PAD specification. This system may be an ND system, or a system from another vendor.

Features

  • Automatic conversion of symbolic name to remote X.25 number. The end user may use this service without knowing where the host is located. The system supervisor has defined the routing through system startup.
  • It is possible to tailor the terminal’s profile to a specified host. This may be done either by local commands, or by the host. For instance, echo and break strategy may be changed by the contents of some parameters. A more efficient communication will be the result.
  • In addition to symbolic names, SCRIPT facilities are available. This provides the end user with a high level of transparency. By typing one command the following will be obtained: connection to, log-in to and starting an application in the host.
  • The COSMOS X.29 PAD may run on the system where the COSMOS X.25 Option resides, or on any other system in the COSMOS network which can access this X.25 gateway.
  • To ensure that remotely connected terminals cannot use this expensive service (costs to the PTT), the PAD is implemented with a bar. This bar gives access only to users physically connected to the computer where the COSMOS X.29 PAD resides.
  • It is possible to create both system entries and private entries. System entries include hosts which all users of the PAD may use. In addition, private entries may be created, which are then only available to one user.
  • The COSMOS X.29 PAD is easy to install. When the installation is done, you can start it by just typing 'X29-PAD C-R'.
  • SINTRAN facilities have been used to make the PAD service easy to use both for 'advanced' users and users with no extensive knowledge of the CCITT standards and protocols.
  • A logging facility is supported by the COSMOS X.29 PAD. The whole dialogue with the host, or parts of it, may be logged on a file.

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Product Description

The current implementation of COSMOS X.29 PAD is based on the 1980 version of X.3, X.28 and X.29 standards (yellow book). The X.29 program runs as a standard re-entrant subsystem using the XMSG interprocess communication system to communicate with the X.25 module.

The PAD supports two kinds of lists, a host entry list and a profile list. The host entry list contains at least one entry per host to be addressed by the PAD. A unique name, like a SINTRAN file name, is associated with each entry. At connect time, this name, rather than the direct X.25 address (DTE number plus sub-address or PTT number) is referred to in the CONNECT-TO command. The standard PAD connection procedure, the PTT way, may of course be used, for instance, giving the DTE number to the host in the CONNECT-TO command.

An entry contains all the information necessary to establish the X.25 connection to the relevant host and to set up an initial operational mode (initial profile). The entry may even contain the first commands to be sent to the remote host. The profile list must contain all the profiles referred to in the host entry list. The profiles are also named symbolically like the entries in the host entry list.

The profile and the host entries appearing to the COSMOS X.29 PAD user are of two types: System entries or private entries. Only the system supervisor is allowed to create, change or delete system entries. The user is allowed to create, change or delete his own private entries, which then appear as additions to the system lists. These private entries are saved on a local user file, if desired.

There are two modes of operating the PAD program. Starting the program, you will enter the end-user mode. In this mode only the most common commands will be listed when the HELP command is used. To enter the advanced mode you must give a special command. All commands available will then be listed when the help command is given.

The COSMOS X.29 PAD also supports a logging facility. The user may log on a file parts of, or the complete, dialogue with the remote host. Using this facility the user may achieve a one-way file transfer capability (file transfer from the remote host to the local ND system).

Requirements

  • ND 10573 COSMOS X.25 Network Option with prerequisites.
  • ND 10373 IS-XMSG / ND 10130 XMSG / ND 10374 COSMOS Basic Module.

Documentation

  • COSMOS X.29 PAD User Guide ..................ND-60.192
  • SINTRAN III Reference Manual ...............ND-60.128
  • SINTRAN III System Supervisor ..............ND-60.103
  • COSMOS Operator’s Guide .......................ND-30.025
  • COSMOS X.25 Option Operator’s Guide.....ND-30.034