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Software Communications

ND 10578 COSMOS X.29 SERVER

graph TB
    subgraph SINTRAN Op. System
        TAD1(TAD)
        TAD2(TAD)
        XMSG((IS) XMSG)
        SERVER(X.29 SERVER)
    end
    XMSG --> SERVER
    subgraph X.25
        Packet(Packet level)
        Link(Link level)
        Physical(Physical level)
    end
    SERVER --> X.25

    PAD["Any «PAD terminal» (ND or not)"]
    X25[X.25 NETWORK]

    PAD --> X25

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.

The host that receives the packets from a PAD needs a system that can unpack received packets and send them as asynchronous terminal characters to the operating system. The system also handles packing and sending of the characters received in response.

NORSK DATA’s system COSMOS X.29 SERVER, handles this «host-service». With this system, terminals connected to a PTT PAD service, or terminals on computers with a similar PAD, can access the ND computer as if they were directly connected. The computers with the PAD service need not be ND computers.

Terminals directly connected to an ND system can be made to conform to the X.3, X.28 and X.29 (Triple-X) protocols using the ND 10405 COSMOS X29 PAD. For more information about this product, see the ND 10405 COSMOS X.29 PAD data sheet.

FEATURES

  • One server may give the «PAD-user» access to different hosts in one COSMOS network. The X.29 SERVER located in the same computer as the «X.25 Gateway» will find out which computer in the network the incoming call wants to access. The routing to that particular host will be handled by COSMOS.
  • It is possible to authorize certain DTEs for access via the X.29 SERVER. Other DTEs will be refused. This facility is an option.
  • The accounting system will register all the dialogues from X.29 PADs. Each time a user logs in via X.29, the following is logged:
    • Log-in time
    • Log-in user name
    • The caller’s DTE number
    • Statistics (character/packets sent/received)
    • Upon log-out, the duration will be calculated (from log-in until log-out). Rejected calls will also be logged with the caller’s DTE number.
  • A log facility is implemented.
    • Different parts or the total communication between the SERVER and its environment may be logged.
    • System supervisor can turn the log on and off. The log file can be read without any preprocessing.
  • The number of simultaneous calls will initially be set to 5. This may be increased by changing a single parameter.
  • The server will not break the X.25 connection after a logout. It is possible for an X.29 PAD user to log in and out several times, without having to establish a new X.25 connection for each log-in.

10578.7000-1184

[Photo: Scanned by Jonny Oddene for Sintran Data © 2021]

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Product Description

The COSMOS X.29 SERVER is an RT program using page table 2. (ISX)MSG is used when data is exchanged between the X.29 SERVER and a TAD (Terminal Access Device), which is the «port» to the SINTRAN Operating System.

The server can handle all SINTRAN echo and break strategies. Hence, it is possible to run screen oriented software from an X.29 PAD terminal. However it should be noted that the X.29 protocol was originally designed for hard-copy, line-oriented terminals. Due to this fact, the efficiency of using the PAD for screen-oriented applications may be reduced.

The accounting system provided by COSMOS X.29 SERVER uses two different files. When one file is filled, a message is printed on the SINTRAN error device telling the system supervisor to save the contents of the file. Then the other accounting file is opened.

To authorize certain DTEs for access, a table of DTE numbers must be created. This is easily done by the system supervisor. For all incoming calls, the server will check the DTE number of the caller against this table. If no match is found, the server will send an X.25 disconnect. At the same time the calling PAD’s DTE number will be logged on one of the two accounting files. The maximum number of DTE numbers is 64. It is possible to run a server with no access restriction at all.

Requirements

  • ND 10374 COSMOS Basic Module.
  • ND 10573 COSMOS X.25 Network Option. (with prerequisites)

Documentation

Manual Code
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