IBM X.25 Co-Processor Support Program
User's Guide

Fourth Edition, June 1996


Table of Contents

Special notices

About this book

  • The IBM X.25 Co-Processor Support Program package
  • Related publications
  • Introducing the IBM X.25 Co-Processor Support Program

  • About this Topic
  • IBM X.25 Co-Processor Support Program
  • Components of the IBM X.25 Co-Processor Support Program
  • IBM X.25 Interface Co-Processor/2 adapter
  • IBM Realtime Interface Co-Processor Multiport/2 adapter
  • Line requirements
  • Overview of X.25
  • X.3, X.28, and X.29
  • Packet switching data networks
  • Packet switching
  • Network addresses
  • Switched and permanent virtual circuits
  • Installation, configuration, and initialization
  • Installing the IBM X.25 Co-Processor Support Program

  • About this Topic
  • Prerequisites
  • Installing the software
  • Procedure
  • Other considerations
  • Configuring the links

  • Before you start configuring
  • The steps involved
  • Parameter checklists
  • Logical adapter numbers
  • Configuration panels
  • Function key assignment
  • Starting configuration
  • When to configure
  • X25 configuration command
  • Main menu
  • Using the panels to configure the links
  • X.25 link-profile panel
  • X.25 frame-parameters panel
  • X.25 packet parameters panel
  • X.25 packet time outs panel
  • X.25 SVC profile panel
  • X.25 PVC profile panel
  • Completing configuration
  • Trace facilities, nicknames, and incoming call routing

  • About this Topic
  • Trace facilities panel
  • Call nicknames panel
  • Incoming call routing panel
  • Initializing the IBM X.25 Co-Processor Support Program

  • About this Topic
  • X25 command
  • X.25 parameter file
  • Loading and running applications
  • Formatting the error log
  • Dumping the IBM X.25 Interface Co-Processor/2 adapters
  • Capturing display messages from applications
  • Terminating the IBM X.25 Co-Processor Support Program
  • Using the supplied facilities

  • About this Topic
  • Link management
  • Function keys
  • Help information
  • Link-management main-menu panel
  • Trace facilities panel
  • Link-management panel
  • Event management
  • Link-error panel
  • Incoming-call-received panel
  • Dealing with problems

  • About this Topic
  • Configuration errors
  • General errors
  • Problems with files
  • Initialization errors
  • General errors
  • Files missing or corrupt
  • Parameter file contents
  • Loading an application
  • Management errors
  • General errors
  • Appendix A. Parameter checklist

  • X.25 link profile
  • X.25 link profile - frame parameters
  • X.25 link profile - packet parameters
  • X.25 link profile - packet time outs
  • X.25 link profile - SVC parameters
  • X.25 link profile - PVC parameters
  • Appendix B. Glossary

    INTERNATIONAL BUSINESS MACHINES PROVIDES THIS PUBLICATION "AS IS," WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Some states do not allow disclaimer of express or implied warranties in certain transactions; therefore, this statement may not apply to you. This publication could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein; these changes will be incorporated in revisions of the publication. IBM may make improvements and/or changes in the product(s) and/or the program(s) described in this publication at any time.

    It is possible that this publication may contain references to, or information about, IBM products (machines or programs), programming, or services that are not announced in your country. Such references or information must not be construed to mean that IBM intends to announce such IBM products, programming, or services in your country.

    (C) Copyright IBM Corporation 1989, 1990, 1991
    All rights reserved.


    Approval for use

    The IBM X.25 Co-Processor Support Program has been approved for use in any IBM Micro Channel Personal System/2, connected to packet switching services in the countries in which the product is announced, under the conditions in the instructions for use.

    If you change any part of the hardware or software of this product (other than for normal configuration), you must check with your PTT or network provider that product approval is still valid. Application programs that you develop using the API of the IBM X.25 Co-Processor Support Program may also need approval from your PTT or network provider.


    Special notices

    Any reference to an IBM licensed program or other IBM product in this publication is not intended to state or imply that only IBM's program or other product may be used. Any functionally equivalent program that does not infringe any of IBM's intellectual property rights may be used instead of the IBM product. Evaluation and verification of operation in conjunction with other products, except those expressly designated by IBM, is the user's responsibility.

    IBM may have patents or pending patent applications covering subject matter in this document. The furnishing of this document does not give you any license to these patents. You can send license enquiries, in writing, to the IBM Director of Commercial Relations, IBM Corporation, Purchase, NY 10577.

    The following terms, denoted by an asterisk ( * ), used in this publication, are trademarks or service marks of the IBM Corporation in the United States or other countries: (Ref #1.)

    IBM,  Personal System/2,  PS/2,  Operating System/2,  OS/2,
    Micro Channel,  Macro Assembler/2,  C/2,  Pascal/2
    

    The following terms, denoted by a double asterisk ( ** ), used in this publication, are trademarks or service marks of the following companies in the United States or other countries:

    Lattice C           Microsoft Corporation
    Turbo C             Borland International
    Turbo Pascal        Borland International
    Transpac            Transpac S.A.
    

    No statements contained in this documentation shall affect the statutory rights of consumers.


    About this book

    IBM trademarks. For a list of trademarks, see topic reference #1.

    This book is primarily intended for administrators who are responsible for the IBM X.25 Co-Processor Support Program. These are mainly systems people who install, configure, and customize the system. However, part of this guide may be useful to nontechnical people who simply need to use the network.

    The book is organized as follows:

    A glossary is provided at the back of the book.


    The IBM X.25 Co-Processor Support Program package

    The IBM X.25 Co-Processor Support Program package contains:


    Related publications

    You can find information on installing your IBM X.25 Interface Co-Processor/2 adapter in the IBM X.25 Interface Co-Processor/2: Installation Instructions, supplied with the adapter.

    Full technical information about the IBM X.25 Interface Co-Processor/2 adapter is given in the IBM X.25 Interface Co-Processor/2: Technical Reference manual.

    The IBM Realtime Interface Co-Processor library contains manuals giving other technical information about the IBM X.25 Interface Co-Processor/2 adapter and the software that can be run on it. One manual that is relevant to installation is that supplied with the Realtime Interface Co-Processor DOS Support Package. Other publications for the Realtime Interface Co-Processor DOS Support Package are listed in the IBM X.25 Co-Processor Support Program: Programmer's Reference manual.

    The IBM X.25 Co-Processor Support Program: Programmer's Reference, describes how to write your own programs using the X.25 application programming interface (API). This manual is provided as part of the IBM X.25 Co-Processor Support Program package.

    In addition to the literature listed above, it could be useful to refer to other published material on packet switching and X.25. For example, your network provider may publish introductory material or booklets of network-specific information.

    The definitive X.25 reference is the International Telegraph and Telephone Consultative Committee (CCITT) Recommendation X.25.


    Introducing the IBM X.25 Co-Processor Support Program


    About this Topic

    This topic provides background information about the IBM X.25 Co-Processor Support Program and about packet switching data networks (PSDNs). It also describes how you can use the IBM X.25 Co-Processor Support Program to access such networks.

    You may have purchased the IBM X.25 Co-Processor Support Program because it is required by a specific X.25 application program. If so, refer to the documentation that came with the application program.


    IBM X.25 Co-Processor Support Program

    Components of the IBM X.25 Co-Processor Support Program

    The IBM X.25 Co-Processor Support Program described in this book consists of software that allows your IBM PS/2 to communicate with other computers through a PSDN. The IBM X.25 Co-Processor Support Program includes components that:

    The IBM X.25 Co-Processor Support Program also provides you with facilities to set up the system on your PS/2 computer. These are described later in this book.

    IBM X.25 Interface Co-Processor/2 adapter

    You install an IBM X.25 Interface Co-Processor/2 adapter in one of the expansion slots of your PS/2 in the same way as other optional adapters. A cable runs from it to data circuit-terminating equipment (DCE) connected to the network. The DCE is normally supplied by your Post, Telegraph and Telephone authority (PTT) or network provider.

    The IBM X.25 Interface Co-Processor/2 adapter has its own microprocessor and memory, and circuits to provide a communications link. Before it can be used to communicate, it has to be loaded with software supplied with the IBM X.25 Co-Processor Support Program. This code is loaded when the software is initialized.

    IBM Realtime Interface Co-Processor Multiport/2 adapter

    IBM X.25 Interface Co-Processor/2 adapters must be installed in numerically lower physical slots than an IBM Realtime Interface Co-Processor Multiport/2 adapter. It therefore follows that if any IBM Realtime Interface Co-Processor Multiport/2 adapters are present they must be in numerically higher physical slots.

    IBM Realtime Interface Co-Processor Multiport/2 adapters must not be installed in slots between any IBM X.25 Interface Co-Processor/2 adapters.

    Note: The PS/2 slots are numbered from 1 upward; the slot numbers are engraved on the back panel of the system unit. See the Quick Reference manual for your PS/2 computer for details of physical slot numbering.

    Line requirements

    You need an X.25 line to connect your PS/2 to a PSDN. A connection from the PS/2 to a PSDN is called an X.25 "link". You can have links to more than one PSDN from your PS/2, but each link needs a separate IBM X.25 Interface Co-Processor/2 adapter.

    Lines on public networks may take some time to obtain. If you have not already done so, contact your public network provider (usually the PTT) well before you need the line. When you apply, you choose various options, such as the number and type of logical channels you require, the speed of line, and so on.

    You can connect two IBM X.25 Interface Co-Processor/2 adapters together by using a DCE eliminator. This might be very useful for testing purposes. The adapters can be installed in the same or in two different PS/2 computers.


    Overview of X.25

    Network communication between computers is similar to telephone communication between people. When you pick up a phone and dial a number, a path is set up across the lines of the telephone network (if the necessary lines are not busy). When the call is answered, the conversation normally lasts until someone hangs up.

    For this to work, a protocol - a set of rules governing the operation of the system - is needed. One rule, for example, is that the connection is held until it is deliberately broken by one of the users. Other rules provide for signals to indicate "line busy," "number unobtainable", and so on.

    Given the necessary hardware and programs, one computer can be connected to another across the lines of a network, and they can exchange messages and files by sending and receiving data signals. Again, a protocol is needed, equivalent to the telephone network.

    Several different protocols exist but the one described here is X.25, which simply stands for the 25th recommendation in a series made by the International Telegraph and Telephone Consultative Committee (CCITT).

    There are several versions of the CCITT X.25 recommendation. The first generally implemented version was published in 1980. A version with additional features was published in 1984. You need to know which version of the X.25 protocol your network supports. (Or the best approximation - your network supplier may not support any of the recommendations completely.)

    X.3, X.28, and X.29

    You can connect asynchronous (stop/start) terminals to a PSDN. Each terminal is connected through a packet assembler/disassembler (PAD). This is a combination of hardware and software that assembles the single characters transmitted by the terminal into packets which can then be sent to the network. The PAD also disassembles packets received from the network into character strings suitable for receipt by the terminal.

    There are three CCITT recommendations concerning PADs: X.3, X.28, and X.29. These recommendations are supported by the IBM X.25 Co-Processor Support Program and are described in the IBM X.25 Co-Processor Support Program: Programmer's Reference.


    Packet switching data networks

    A packet switching data network (PSDN) is similar to a telephone network, but carries messages between computers. These messages may be computer files, parts of a data entry transaction, or other data.

    The messages are split into small subsections called packets. The most common type of PSDNs use the X.25 protocol specified by the CCITT to communicate with attached computers.

    Figure 1 shows how several PS/2 computers might be connected over a PSDN using the X.25 protocol.

    Figure 1. A PSDN implementing the X.25 protocol

                   +--------+       +---------+
                   |        |       |         |
                   +---+----+       +----+----+
                       |                 |
                       |              ---+-----               +-----------+
                 ------+----         /         \              |           |
                /           \       /           \             +-----+-----+
        -------/             \     /             \                  |
       /                      -----          -----                  |
      /                 PSDN                /                     --+--
     \                                     \       +--------+    /     \
      \              ----------             \------+        +---/       \
       \            /          \             \     +--------+   \       /
        \          /            --+---\       \                  \     /
         -----+---/               |    \-------\                  --+--
              |                   |                                 |
        +-----+-----+        +----+-----+                           |
        |           |        |          |                    +------+------+
        +-----------+        +----------+                    |             |
                                                             +-------------+
    

    Packet switching

    In a PSDN the data to be sent is split into one or more packets, together with addressing and control information. The resulting packets can be sent through a suitable path in the network and the packets of many different users can share the same network routes and lines. A single physical line into your office can handle several calls concurrently.

    Network addresses

    Each X.25 connection, or "link", to a PSDN is identified by a number called the Network User Address (NUA). A full NUA includes a 3-digit country code and a National Terminal Number (NTN); these uniquely identify the X.25 connection throughout the world.

    In public networks, your PTT or network provider gives you a number as part of your network subscription. This may be the full NUA or possibly your NTN only.

    The maximum number of digits allowed in an NUA (in the 1980 CCITT X.25 recommendation) is 15. If a particular network requires you to use fewer than 15 digits (for example, British Telecom expect 13), you can allocate the "unused" additional digits as a suffix to identify individual users of your PS/2. The 1984 X.25 protocol allows each user to have an Extension Address of up to 32 digits; this gives you a better method of identifying users if you have it available.

    A typical NUA structure is shown in Figure 2.

    Figure 2. Network user address structure

       +-- Network user address --+       +- Extension -+
       |   (NUA)                  |       |  address    |
       +-----+ +------------+ +---+       +-------------+
       | 123 | | 1234567890 | | 12|       | 12345....32 |
       +-----+ +------------+ +---+       +-------------+
       Country   National     Suffix        1984 X.25
       code      terminal                   protocol
                 number (NTN)               only
    

    Switched and permanent virtual circuits

    When you make a call over a PSDN you establish contact with another user and thus set up a switched virtual circuit (SVC) between yourself and the other user. Making a call on an SVC usually consists of three stages:

    1. Establishing the call
    2. Sending and receiving data
    3. Terminating the call.

    You can have several SVCs in use at once on one link (you will probably be charged by your network supplier according to the number of SVCs you request).

    The circuit acts in a similar way to a connection made over the normal telephone "switched circuit" network (although no physical switching takes place). An SVC connection lasts only for the duration of the call.

    Some network suppliers allow subscribers to have permanent virtual circuits (PVCs) in addition to SVCs. A PVC is a (virtual) permanent connection between one network user address and another. This might save time and effort, because there is no need to go through the procedures of establishing and terminating calls on PVCs.

    Installation, configuration, and initialization

    Installation

    The IBM X.25 Co-Processor Support Program lets you use an IBM PS/2 (with an IBM X.25 Interface Co-Processor/2 adapter) on a PSDN. However, the software has to be installed on the fixed disk of the computer before you can use it.

    Configuration

    The link also has to be configured before you can use it for the first time. When you configure the system, you give it details about the various choices that were made when the network line was applied for, such as the number of SVCs and PVCs the link supports. You also enter into the system other information supplied by the network provider, such as the network user address. You configure the link by choosing from menu options described in "Configuring the links".

    During configuration, the particular requirements of the network are recorded in "link profile" files in the PS/2. You can configure the system on a computer other than the one you are going to use for the link, or before the adapter is installed. If you do this, you must copy the files to the "target" computer and use them as described in "Configuring the links".

    Initialization

    You also have to initialize the software before use. Initialization consists of loading the code into the PS/2 and activating it. You must do this before loading any X.25 applications.


    Installing the IBM X.25 Co-Processor Support Program


    About this Topic

    This topic explains what you have to do before you can use the IBM X.25 Co-Processor Support Program on a packet switching data network. It tells you:


    Prerequisites

    For a list of trademarks, see reference #1. To use the IBM X.25 Co-Processor Support Program, you need:


    Installing the software

    The following is required for installation:

    Procedure

    The IBM X.25 Co-Processor Support Program was supplied contains a file XINSTALL.BAT that you can use for the installation. The procedure is:

    1. Ensure that the default drive is the one on which the X25 directory is to be created.

    2. Load the supplied diskette in drive A.

    3. Type A: XINSTALL at the > prompt.

    XINSTALL does the following:

    1. Creates a directory named X25 (if it does not already exist)

    2. Copies files from the supplied diskette into the X25 directory

    3. Prompts you to load the diskette supplied with the Realtime Interface Co-Processor DOS Support Package into drive A

    4. Copies the required files from the diskette into the X25 directory

    5. Prompts you to load the option diskette supplied with the IBM X.25 Interface Co-Processor/2 adapter into drive A

    6. Copies the required files from the option diskette into the X25 directory.

    Other considerations

    CONFIG.SYS file

    There must be at least 20 files specified in your CONFIG.SYS file. Refer to the appropriate DOS manual for details.

    Edit your CONFIG.SYS file to contain the lines:

         buffers=20
         files=20
    

    AUTOEXEC.BAT file

    The path set up in your AUTOEXEC.BAT file must include the X25 directory, in addition to any existing directories included in the path. For example, if your file contains the line:

         path c:\;c:\dos
    
    you must edit it to contain:
         path c:\;c:\dos;c:\x25
    
    When you have made these changes, restart DOS by pressing the Ctrl, Alt, and Del keys at the same time. You can then begin configuring your system.

    Extended memory address

    If an extended memory address was set for the window when the system was configured by the X.25 adapter Reference Diskette, the adapter code cannot work and an adapter error code is generated.

    Monitor mode

    If you are using a color monitor, you must not change its mode to "mono". If you do change the mode, the X.25 Co-Processor Support Program cannot initialize the windows necessary for configuration or execution.


    Configuring the links


    Before you start configuring

    You can perform the configuration with or without the IBM X.25 Interface Co-Processor/2 adapter being installed. This allows you to create configuration files on one IBM PC or PS/2, then copy and use the files on the PS/2 that you are going to use. How you use the files is described in "Initializing the IBM X.25 Co-Processor Support Program".

    The steps involved

    To configure the X.25 subsystem, follow these steps:

    1. Copy the Parameter Checklists in Appendix A. Complete these according to the requirements of your system.

    2. Define the profiles for all your links. This creates a separate file for each link profile you define, with a DOS extension of .PRF.

    3. Allocate the logical adapter numbers. This defines the logical adapter number to the link profile. The information is stored in a file called ADAPTER.X25.

    4. Set any required tracing. You need to use the trace facility if you want to set the Trace Options for any links. This information is stored in a file called TRACE.X25.

    5. Define any required nicknames. You use this facility to define nicknames for external X.25 users. This information is stored in a file called NAMES.X25.

    6. Define routing of incoming calls. You use this to define the route that incoming calls must take. This information is stored in a file called ROUTE.X25.

    Parameter checklists

    Each link to the PSDN requires an IBM X.25 Interface Co-Processor/2 adapter installed in the PS/2. A link must be configured before it can be used.

    (Ref #3.) The configuration process needs the entry of technical details about the link. Before you start configuration, you (or your PC administrator) should have entered this information on a copy of the appropriate parameter checklists, which are to be found in Appendix A. If you do not know the technical details, get them from the person who ordered the link. Default values are provided and are shown on each panel. All entries must correspond to the values subscribed to within the network, otherwise intermittent and/or unpredictable failures could occur.

    After you have configured the link you may want to set trace options, nicknames, and incoming call routings. (See "Trace facilities, nicknames, and incoming call routing" for details.) The application you plan to run may affect the particular values you use. You can configure more than one profile for a link, although you can use only one at any time. To use a different profile you must terminate and reinitialize the X.25 subsystem.

    Logical adapter numbers

    (Ref #4.) When doing the configuration, you need to know the logical adapter number of the adapter controlling the link. IBM X.25 Interface Co-Processor/2 adapters are numbered sequentially, starting with 0, according to the physical slots in the PS/2 into which they are plugged, ignoring empty slots and slots used for other adapters. For example, the first IBM X.25 Interface Co-Processor/2 adapter (logical number 0) in your PS/2 is not necessarily the adapter in physical slot number 1; the adapter could be in the second or third physical slot. Details of the physical slot numbering can be found in the Quick Reference manual for your PS/2 computer.

    Configuration panels

    This section tells you how to use the configurator supplied with the IBM X.25 Co-Processor Support Program. It provides assistance on the types of panels and windows that are displayed when running the configurator, and describes the use of the function keys.

    Configuration requires you to record information in several configuration data entry panels. The logical way that the panels are linked is shown in

    Figure 3. Subsystem configuration panels

                         +---------------------+
                         |   Configuration     |
                         |     Main Menu       |
                         +----------+----------+
                                    |
            +------------------+----+-------------+---------+
            |                  |                  |         |
    +-------+------+  +--------+--------+  +------+-----+   |   +---------------+
    |     X.25     |  | Logical Adapter |  |   Trace    |   +---+     Call      |
    | Link Profile |  |    Numbers      |  | Facilities |   |   |   Nicknames   |
    +------+-------+  +-----------------+  +------+-----+   |   +---------------+
           |                                      |         |
     +-----+------+                        +------+-----+   |   +---------------+
     | Set/View   |                        |    Set     |   +---+ Incoming Call |
     |   Link     |                        |   Frame    |       |    Routing    |
     | Profile    |                        |   Level    |       +---------------+
     +-----+------+                        +------+-----+
           |                                      |
     +-----+------+                        +------+-----+
     |  Set/View  |                        |    Set     |
     |    Frame   |                        |   Packet   |
     | Parameters |                        |   Level    |
     +-----+------+                        +------------+
           |
     +-----+------+
     |  Set/View  |
     |   Packet   |
     | Parameters |
     +-----+------+
           |
     +-----+------+
     | Set/View   |
     |  Packet    |
     | Time outs  |
     +-----+------+
           |
     +-----+------+
     | Set/View   |
     |   SVC      |
     | Parameters |
     +-----+------+
           |
     +-----+------+
     | Set/View   |
     |   PVC      |
     | Parameters |
     +------------+
    

    Using the configuration panels

    Displayed options

    The configurator displays a series of panels for defining the X.25 subsystem that you will be using. All of these panels are similar in format. A header line identifies which panel is being displayed and the available function keys are listed at the bottom of the panel. Each panel contains several selectable options. These are selected by using the ^ and V keys. As you select an option it is displayed on the screen in reverse video.

    The displayed options on the main menu panel let you select which function of the configurator you want to use. The options are selected by using the ^ and V and you are taken to the selected function when you press the enter key.

    Types of option field

    There are two types of option fields on the panels:

    1. Options that require alphanumeric input contain a field bounded by [ and ]. When one of these options is selected, pressing alphanumeric keys on the keyboard enters the data in the input field. To delete any data in the field, you must use the delete key.

    2. Options that have predefined alternatives show the default value. When you select an option, a small "window" appears. This tells you what alternatives are available. The window has the current value highlighted in reverse video on the screen. You use the F5 and F6 function keys to scroll through the list of alternatives in the window. As you do this, the value on the main panel automatically changes to match the selected alternative. When the required alternative is highlighted, you can use the ^ or V keys to select another option from the panel, or use any of the available function keys to perform the action that you have selected.
    List panels

    (Ref #5.) Some of the main panels allow the selection of a list panel. To display the list panel you must press the F4 function key. The list panels occupy the full height and most of the right-hand side of the display. The available function keys are also shown on the panels. List panels display the names of previously saved configuration data; for example, link profiles or nicknames.

    List panels let you select an item from the list by using the F5 and F6 function keys, the selected item being highlighted. You can perform a function against the selected item by pressing the corresponding function key. For example, it is possible to load all the values for a previously created link-profile configuration by selecting the link name on the list panel and pressing the F10 function key.

    Function key assignment

    The use of function keys within panels is as follows (although not all panels use all the function keys):

    Esc
    Exit a panel without saving changes to the current panel. (If changes have been made, you are asked if you still wish to quit.)

    F1
    Display help. Help panels are available for each displayed option line. When the help panel is present you can get help on other fields by using the cursor movement keys.

    F3
    Check and save parameters.

    F4
    Display a list. Depending on which panel you are using, this can be a list of link profiles, routing entries, or call nicknames.

    You can load a particular entry from the list on the panel that appears by pressing F10. You can then edit the entry (for example, the link profile) and save it under the same or a different name.

    F5
    Scrolls backward through a list of predefined alternative values for a particular field.

    F6
    Scrolls forward through a list of predefined alternative values for a particular field.

    F7
    Checks that the displayed data is within valid ranges, and, if it is, goes to the previous panel.

    F8
    Checks that the displayed data is within valid ranges, and, if it is, goes to the next panel.

    F10
    Complete the requested action. Use this key when you want the configuration values to be recorded, or (when viewing a list) the selected item to be loaded.

    F12
    Returns to the first panel of a sequence after checking that the displayed data is within valid ranges.

    Starting configuration

    When to configure

    You normally configure the link after installation and before you have initialized the system. You can, however, configure the link at any time: any changes made are not used by the X.25 API until the next time you perform initialization.

    X25 configuration command

    To start the configuration of a link, at the DOS prompt type:

         CD X25
    
    to change to the X25 directory. Then type the X25 command in the following form:
         X25 CONF 
    
    If you use the optional DOS path (shown between the < > symbols) all files produced during configuration are placed in the directory specified in the DOS path, rather than in the current directory. You might find this useful if you are using a single PS/2 computer to create the configuration files for use on other PS/2 computers.

    When you issue the X25 CONF command, the IBM logo appears. To get to the main menu, shown in you must press Enter.

    Main menu

    (Ref #6.)

    This panel provides a list of secondary panels, from which you make selections. (Ref #7.)

    Figure 4. Main Menu panel

     *-----------------------------------------------------------------------------*
     |  X.25 Co-Processor Support:      Configuration  -  Main Menu                |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     |                                                                             |
     |   Select Option and Enter                                                   |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |   1.  Set/View X.25 Link Profiles                                           |
     |   2.  Set/View Logical Adapter Numbers                                      |
     |   3.  Set/View Trace Facilities                                             |
     |   4.  Set/View Call Nicknames                                               |
     |   5.  Set/View Incoming Call Routing                                        |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER ESC=Cancel  F1=Help  ^V=Move Selection Cursor                         |
     |                                                                             |
     *-----------------------------------------------------------------------------*
    

    To make a selection

    When you view the main menu panel, you see one selection line "highlighted" (that is, displayed in reverse video). You can change the selected line by using the cursor movement keys (labeled ^ and V).

    To request the selected secondary panel, press Enter. Alternatively, type the number of the selection (1 through 5). The secondary panel that you selected appears. The secondary panels are described in the following sections.


    Using the panels to configure the links

    Ensure you have the necessary technical details to hand before you start. These details should have been entered on a parameter checklist as described in topic reference #3.

    The ranges of the parameters in the panels that follow can be seen by pressing F1 (the "help" key), or referring to the checklists in Appendix A. "Parameter checklist".

    X.25 link-profile panel

    (Ref #8.)

    Creating a link profile

    You must create a link profile for each adapter in your PS/2. You can create and edit as many link profiles as you like. Each set of link-profile information is held in a file with the name xxxxxxxx.PRF where xxxxxxxx is the link-profile name you type in the first field of this panel. You can see a list of link profiles that have already been set up if you press F4 to get a list panel. (List panels are described in topic reference #5.)

    Each adapter has a logical number assigned to it; this number must relate to a specific link-profile name, as described in topic reference #4. To assign logical adapter numbers to link-profile names, select the "link-profile name" option from the link-profile panel. Press F4 to get a list panel and follow the instructions on the screen. You can either do this as you go along or when you have set up all of your link profiles.

    Note: If you want to change an existing profile, press F4 and select the profile you want from the list that appears. Existing details for this link are displayed, and may be altered, on the various configuration panels described in this section.

    You change the details of the link profile by changing the information shown. You can rename the link profile, if you wish, before saving the changes. When you have made all the changes that you require, return to this panel and press F10 to save the information.

    Figure 5. X.25 Link-profile panel

     *-----------------------------------------------------------------------------*
     | 1.1  X.25 Link Profile                                           1 of 6     |
     *-----------------------------------------------------------------------------*
     | Enter data at  . Use F5 or F6 to select item from displayed alternatives  |
     |                                                                             |
     |                                                                             |
     |  Link profile name                        [        ]                        |
     |  Description                              [                                ]|
     |                                                                             |
     |  Electrical Interface                       X.21 bis/V.24                   |
     |                                                                             |
     |  Logical DTE/DCE                            DTE                             |
     |                                                                             |
     |  Transpac VX32                              NO                              |
     |                                                                             |
     |  Country Code                             [CCITT]                           |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F4=List Profile Names F7=Backward               |
     | F8=Forward  F10=Check and File  ^V=Move Selecion Cursor                    |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Link profile name

    The name by which this link profile is known to the program. The file produced during configuration for this link uses this profile name with an extension of .PRF.

    Description

    Up to 32 characters that describe a particular link profile. This description is returned if you request information about the link when you are running an application.

    Electrical Interface

    The electrical interface through which you are connecting the link.

    Logical DTE/DCE

    Normally you configure a link as Data Terminating Equipment (DTE). If you can connect two adapters together (through a Data Circuit-Terminating Equipment (DCE) eliminator) for testing purposes, you must configure one as a DTE and the other as a DCE.

    Transpac VX32

    This must be set if your link is connected to a French Transpac VX32 data circuit-terminating equipment.

    Country Code

    This field must contain the country code for the network attachment that you require.

    Note: It is a requirement of the PTT attachment-approval conditions that the correct country code is inserted in this field. If you do not know the code for your network supplier, contact your IBM representative for further information.

    X.25 frame-parameters panel

    Setting the frame parameters

    (Ref #10.)

    You use this panel to enter the frame level parameters for this link. Entry fields delimited by '[' and ']' require numeric or alphanumeric entry, other fields give you a choice of one option from a list.

    Figure 6. X.25 Frame parameters panel

     *-----------------------------------------------------------------------------*
     | 1.2. X.25 Link Profile - Frame parameters                        2 of 6     |
     *-----------------------------------------------------------------------------*
     | Enter data at  . Use F5 or F6 to select item from displayed alternatives  |
     |                                                                             |
     |                                                                             |
     |  Window size            (frames)                         [7  ]              |
     |                                                                             |
     |  Frame sequence modulus                                   8                 |
     |                                                                             |
     |  Retry time out         (* 50mS)                         [60 ]              |
     |                                                                             |
     |  Retry count            (frames)                         [20 ]              |
     |                                                                             |
     |  Inoperational time out (seconds)                        [180]              |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER ESC=Cancel  F1=Help  F7=Backward  F8=Forward                          |
     | F12=First Panel  ^V=Move Selection Cursor                                   |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Window size

    The number of frames that can be sent or received by the X.25 adapter without acknowledgment.

    Frame sequence modulus

    The modulus used when generating frame sequence numbers.

    Retry time out

    The time (in 50-millisecond intervals) allowed for response to a frame. If no response is received within the specified time the frame is retransmitted (CCITT T1 timer).

    The retry time out should be set according to the recommendations for the network to which your PS/2 is attached. Such recommendations may be dependent on packet size and line speed. If no recommendations exist, you should set the value to at least 2½ times the time taken to transmit the maximum packet size. For example, a line speed of 9600 bits per second and a packet size of 1024 bytes is a total of 8192 bits (each byte being 8 bits). Therefore the transmission time is 8192 bits divided by 9600 seconds, which equals 853 milliseconds. Multiplying 853 milliseconds by 2½ equals 2132.5 milliseconds, so you should set T1 to 43, which, in 50-millisecond intervals, gives a T1 value of 2150 milliseconds.

    Retry count

    The number of transmissions of a frame before the link is considered broken (CCITT N2 counter).

    Inoperational time out

    The time a link can remain idle before it is considered broken (ISO T4 timer).

    X.25 packet parameters panel

    Setting the packet parameters

    (Ref #11.)

    You use this panel to enter the packet-level parameters for this link.

    Figure 7. X.25 Packet Parameters panel

     *-----------------------------------------------------------------------------*
     | 1.3. X.25 Link Profile  - Packet Parameters                      3 of 6     |
     *-----------------------------------------------------------------------------*
     | Enter data at  . Use F5 or F6 to select item from displayed alternatives  |
     |                                                                             |
     |                                                                             |
     |  Number of PVCs                                          [0 ]               |
     |  Lowest PVC channel number                                0 to 4095         |
     |                                                                             |
     |  Number of Incoming only SVCs                            [0   ]             |
     |  Lowest Incoming only SVC number                         [1    ]            |
     |                                                                             |
     |  Number of Bothway SVCs                                  [8   ]             |
     |  Lowest Bothway SVC number                               [2    ]            |
     |                                                                             |
     |  Number of Outgoing only SVCs                            [0   ]             |
     |  Lowest Outgoing only SVC number                         [10   ]            |
     |                                                                             |
     |  Packet sequence number modulus                           8                 |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F7=Backward  F8=Forward                         |
     | F12=First Panel  ^V=Move Selection Cursor                                   |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Number of PVCs

    The number of Permanent Virtual Circuits (PVCs) that can be used on the link.

    Lowest PVC channel number

    The lowest PVC channel number can be set to any value between 0 and 4095 in the packet panel of the configurator. This is normally set to 1 but some networks, such as the French Transpac, require it to be 0.

    Number of Incoming only SVCs

    The number of SVCs that accept only incoming calls.

    Lowest Incoming only SVC number

    The lowest number that can be used for incoming only SVCs. This number must be greater than the highest PVC number.

    Number of Bothway SVCs

    The number of SVCs that accept both incoming and outgoing calls.

    Lowest Bothway SVC number

    The lowest number that can be used for bothway SVCs. This number must be greater than the highest PVC number and incoming SVC number.

    Number of Outgoing only SVCs

    The number of SVCs that accept only outgoing calls.

    Lowest Outgoing only SVC number

    The lowest number that can be used for outgoing only SVCs. This number must be greater than the highest number of the other SVCs or PVCs.

    Packet sequence number modulus

    The modulus used when generating packet sequence numbers.

    Total number of channels configured

    The X.25 pool size and adapter memory represent a finite resource for the support of virtual circuits (VCs). The upper limit of VCs that may be used without degrading performance or meeting out-of-resource errors depends on the maximum packet size configured, the number of VCs configured, and the actual traffic flow.

    For example, a higher number of VCs should be possible when they are used for terminal support, with intermittent data flow dependent on the operator interaction, rather than all VCs in heavy data flow for (say) file transfer.

    You should, therefore, limit the maximum packet size to the smallest acceptable value in the configuration. You should also set the X.25 memory pool value as large as possible, remembering that when X.25 is loaded the pool memory is allocated for X.25 use only and cannot be used for applications.

    X.25 packet time outs panel

    Setting up packet time outs

    (Ref #12.)

    You use this panel to set up packet time outs for this link. All fields require numeric entry.

    Figure 8. Packet time outs panel

     *-----------------------------------------------------------------------------*
     | 1.4   X.25 Link Profile - Packet time outs                       4 of 6     |
     *-----------------------------------------------------------------------------*
     |                                                                             |
     | Enter data at [ ].                                                          |
     |                                                                             |
     |                                                                             |
     |  Restart request time out     (seconds)                  [180 ]             |
     |  Call request time out        (seconds)                  [200 ]             |
     |  Reset request time out       (seconds)                  [180 ]             |
     |  Clear request time out       (seconds)                  [180 ]             |
     |  Acknowledgment time out      (seconds)                  [0   ]             |
     |  Data packet time out         (seconds)                  [0   ]             |
     |  Interrupt packet time out    (seconds)                  [0   ]             |
     |                                                                             |
     |  Reset request retry count    (packets)                  [5   ]             |
     |  Clear request retry count    (packets)                  [5   ]             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------|
     | ENTER  ESC=Cancel  F1=Help  F7=Backward  F8=Forward                         |
     | F12=First Panel  ^V=Move Selection Cursor                                   |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Restart request time out

    The time allowed for a response to a Restart packet. If a response is not received within the time that you specify, the packet is retransmitted (CCITT T20).

    Call request time out

    The time allowed for a response to a Call Request packet. If a response is not received within the time that you specify, a Call Clear is transmitted (CCITT T21).

    Reset request time out

    The time allowed for a response to a Reset Request packet. If a response is not received within the time that you specify, the packet is retransmitted (CCITT T22).

    Clear request time out

    The time allowed for a response to a Clear Request packet. If a response is not received within the time that you specify, the packet is retransmitted (CCITT T23).

    Acknowledgment time out

    Ensures that no packet-level acknowledgment is lost. This timer is restarted every time an acknowledgment (P(R)) is sent. A value of zero disables the timer (ISO T24 timer).

    Data packet time out

    The time allowed for acknowledgment of a Data packet. If a response is not received within the specified time, some packets may have been lost. The virtual circuit is then reset. A value of zero disables the timer (ISO T25 timer).

    Interrupt packet time out

    The time allowed for confirmation of an Interrupt packet. If a confirmation is not received within the specified time, the virtual circuit is reset. A value of zero disables the timer (ISO T26 timer).

    Reset request retry count

    The number of times the Reset Request packet is retransmitted before the link is restarted.

    Clear request retry count

    The number of times the Clear Request packet is retransmitted before the packet layer is considered broken.

    X.25 SVC profile panel

    Setting SVC profile parameters

    (Ref #13.)

    You use this panel to enter the parameters for all switched virtual circuits (SVCs) on this link. The first eight fields require numeric entry and the last field requires you to select from a list.

    Figure 9. X.25 SVC Parameters panel

     *-----------------------------------------------------------------------------*
     | 1.5. X.25 Link Profile - SVC Parameters                          5 of 6     |
     *-----------------------------------------------------------------------------*
     | Enter data at [ ]. Use F5 or F6 to select item from displayed alternatives  |
     |                                                                             |
     |                                                                             |
     |  Default Incoming packet size (bytes)                    [128 ]             |
     |  Maximum Incoming packet size (bytes)                    [128 ]             |
     |                                                                             |
     |  Default Outgoing packet size (bytes)                    [128 ]             |
     |  Maximum Outgoing packet size (bytes)                    [128 ]             |
     |                                                                             |
     |  Default Incoming window size (packets)                  [2   ]             |
     |  Maximum Incoming window size (packets)                  [2   ]             |
     |                                                                             |
     |  Default Outgoing window size (packets)                  [2   ]             |
     |  Maximum Outgoing window size (packets)                  [2   ]             |
     |                                                                             |
     |  Maximum throughput class     (bits per second)           9600              |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F7=Backward  F8=Forward                         |
     | F12=First Panel  ^V=Move Selection Cursor                                   |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Default Incoming packet size

    The number of data bytes that can be received in each packet.

    Maximum Incoming packet size

    The maximum negotiable incoming packet size.

    Default Outgoing packet size

    The number of data bytes that can be transmitted in each packet.

    Maximum Outgoing packet size

    The maximum negotiable outgoing packet size.

    Default Incoming window size

    The number of packets that can be received over the SVC without acknowledgment. This value is set by your network administrator.

    Maximum Incoming window size

    The maximum negotiable incoming window size.

    Default Outgoing window size

    The number of packets that can be transmitted over the SVC without acknowledgment. This value is set by your network administrator.

    Maximum Outgoing window size

    The maximum negotiable outgoing window size.

    Maximum throughput class

    Maximum rate at which data can be sent to or received from the network.

    X.25 PVC profile panel

    Setting PVC profile parameters

    (Ref #14.)

    The system presents you with a panel for each permanent virtual circuit (PVC). You use these panels to enter the parameters for all PVCs on the link. If you have no PVCs on the link being configured, ignore this panel.

    Note: You do not have to configure all PVCs; a PVC that is not configured uses the same configuration as the next, lower-numbered PVC. For example, if numbers 0 and 5 are configured, 1 through 4 use the same configuration information as number 0 and numbers from 6 upward use the configuration information for number 5.

    Figure 10. X.25 PVC Parameters panel

     *-----------------------------------------------------------------------------*
     | 1.6.  X.25 Link Profile - PVC Parameters                         6 of 6     |
     *-----------------------------------------------------------------------------*
     | Enter data at [ ]. Use F5 or F6 to select item from displayed alternatives  |
     |                                                                             |
     |                                                                             |
     |  PVC number                                              [0  ]              |
     |                                                                             |
     |  Incoming packet size  (bytes)                           [128 ]             |
     |  Outgoing packet size  (bytes)                           [128 ]             |
     |                                                                             |
     |  Incoming window size  (packets)                         [2   ]             |
     |  Outgoing window size  (packets)                         [2   ]             |
     |                                                                             |
     |  PVC Protocol                                            X.25               |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F3=Check and File  F4=List PVC Entries          |
     | F7=Backward  F12=First Panel  ^V=Move Selection Cursor                      |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    PVC number

    The logical channel number of the PVC being configured.

    Incoming packet size

    The number of data bytes that can be received in each packet.

    Outgoing packet size

    The number of data bytes that can be transmitted in each packet.

    Incoming window size

    The number of packets that can be received over the PVC without acknowledgment. This value is set by your network administrator.

    Outgoing window size

    The number of packets that can be transmitted over the PVC without acknowledgment. This value is set by your network administrator.

    PVC Protocol

    The PVC can be used for X.25 or SNA over X.25. The SNA mode can be 1980 or 1984.


    Completing configuration

    Storing the configuration information

    You have finished configuring your X.25 system when you have produced all the link profiles that you want. Press F12 to return to the Link-Profile panel and then press F10 to store the parameters for each configuration. When you have defined all your required configurations, press F7 to return to the main menu panel shown in topic reference #7.

    (The configuration information is stored on the fixed disk of your PS/2 and is used when you carry out the initialization of the system.)

    Assigning a logical adapter number to a link

    Each link needs to have a logical adapter number assigned to it, as described in topic reference #4. To do this, return to the main menu shown in topic reference #7 and select the second line: "Set/View Logical Adapter Numbers". Follow the instructions on the screen to assign logical adapter numbers to the link-profile names that you have allocated.

    Configuring for another PS/2

    (Ref #15.)

    If the configuration that you have just done is for use on a PS/2 other than the one you used, copy the .PRF and the .X25 files that you created onto a diskette. You can now install the files on the "target" PS/2.

    Using trace facilities, nicknames, and routing information

    You can now set the optional trace parameters, nicknames, and routing information. To do this, follow the instructions in "Trace facilities, nicknames, and incoming call routing".


    Trace facilities, nicknames, and incoming call routing


    About this Topic

    The basic configuration that you must do for every link before you can use it was described in "Configuring the links". The following sections describe how you can add extra configuration information. Your applications may require this information before they can be run.

    Note: Applications that are developed to use the IBM X.25 Co-Processor Support Program should have documentation that describes how to set these parameters. See your programmer or network specialist for details.

    Using secondary panels from the configuration main menu you can:

    You access these extra configuration panels, described in the following sections, by selecting options 3, 4, and 5 from the configuration main menu shown in topic reference #7.

    Trace facilities panel

    When running your applications, you might find it necessary to keep a track of certain events. To do this you must set up the "trace" information in the following three panels. You use the panels to specify the frames and packets that you want to be traced by the system, and whether you want them to be traced in either or both directions. (You actually start and stop the tracing by using the link-management facility described in "Using the supplied facilities" or by similar facilities in your own application.)

    The three panels are shown in The guidelines for entering data on the screen are the same as in the configuration panels.

    Trace facilities (panel 1 of 3)

    Figure 11. X.25 Trace Facilities (panel 1 of 3)

     *-----------------------------------------------------------------------------*
     | 3.1  Trace Facilities                                              1 of 3   |
     *-----------------------------------------------------------------------------*
     |                                                                             |
     | Enter data at [ ].  Use F5 and F6 to select item from displayed alternatives|
     |                                                                             |
     |  Trace entry name                         [TRACE   ]                        |
     |  Description                              [                                ]|
     |                                                                             |
     |  Link profile name                        [LINK    ]                        |
     |                                                                             |
     |                                                                             |
     |  Direction of Frames to capture            Neither                          |
     |                                                                             |
     |  Direction of Packets to capture           Neither                          |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F4=List Trace Entries  F7=Backward              |
     | F8=Forward  F10=Check and File  ^V=Move Selection Cursor                    |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Trace entry name

    Eight-character name, which identifies the trace entry.

    Description

    Up to 32 characters of any text you want to input.

    Link profile name

    Name previously given to a link profile. This entry identifies the link (adapter) on which you want to use the trace facility.

    Direction of Frames to capture

    The direction of frames that trace captures. You can choose from:

    Direction of Packets to capture

    The direction of packets that trace captures. You can choose from:

    Trace facilities (panel 2 of 3 - Frame Level)

    Figure 12. X.25 Trace Facilities (panel 2 of 3)

     *-----------------------------------------------------------------------------*
     | 3.2  Trace Facilities - Frame Level                                2 of 3   |
     *-----------------------------------------------------------------------------*
     |                                                                             |
     | Use F5 and F6 to select item from displayed alternatives                    |
     |                                                                             |
     |  Log RR Frames                                               NO             |
     |  Log RNR Frames                                              NO             |
     |  Log REJECT Frames                                           NO             |
     |  Log SABM Frames                                             NO             |
     |  Log DM Frames                                               NO             |
     |  Log DISCONNECT Frames                                       NO             |
     |  Log UA Frames                                               NO             |
     |  Log FRMR Frames                                             NO             |
     |  Log ERROR Frames                                            NO             |
     |  Log INFORMATION Frames                                      NO             |
     |  Enable capture of Frame contents                            NO             |
     |                                                                             |
     |  Enable line control diagnostics                             NO             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F7=Backward  F8=Forward                         |
     | F12=First Panel  ^V=Move Selection Cursor                                   |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Log RR Frames

    Whether to capture Receiver Ready frames.

    Log RNR Frames

    Whether to capture Receiver Not Ready frames.

    Log REJECT Frames

    Whether to capture Reject frames.

    Log SABM Frames

    Whether to capture Set Asynchronous Balanced Mode frames.

    Log DM Frames

    Whether to capture Disconnect Mode frames.

    Log DISCONNECT Frames

    Whether to capture Disconnect frames.

    Log UA Frames

    Whether to capture Unnumbered Acknowledgment frames.

    Log FRMR Frames

    Whether to capture Frame Reject frames.

    Log ERROR Frames

    Whether to capture Error frames.

    Log INFORMATION Frames

    Whether to capture Information frames.

    Enable capture of Frame contents

    Whether to capture frame contents.

    Enable line control diagnostics

    Whether to enable line control diagnostics.

    Trace facilities (panel 3 of 3 - Packet Level)

    Figure 13. X.25 Trace Facilities (panel 3 of 3)

     *-----------------------------------------------------------------------------*
     | 3.3  Trace Facilities - Packet Level                               3 of 3   |
     *-----------------------------------------------------------------------------*
     |                                                                             |
     | Use F5 and F6 to select item from displayed alternatives                    |
     |                                                                             |
     |  Log DATA Packets                                            NO             |
     |  Log RR and RNR Packets                                      NO             |
     |  Log INVALID Packets                                         NO             |
     |  Log CALL Packets                                            NO             |
     |  Log CLEAR Packets                                           NO             |
     |  Log RESET Packets                                           NO             |
     |  Log DIAGNOSTIC Packets                                      NO             |
     |  Log RESTART Packets                                         NO             |
     |  Log ERROR Packets                                           NO             |
     |  Log IGNORED Packets                                         NO             |
     |                                                                             |
     |  Enable capture of Packet contents                           NO             |
     |  Enable line control diagnostics                             NO             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F7=Backward  F12=First Panel                    |
     | ^V=Move Selection Cursor                                                    |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Log DATA Packets

    Whether to capture Data packets.

    Log RR and RNR Packets

    Whether to capture Receiver Ready and Receiver Not Ready packets.

    Log INVALID Packets

    Whether to capture Invalid packets.

    Log CALL Packets

    Whether to capture Call packets.

    Log CLEAR Packets

    Whether to capture Clear packets.

    Log RESET Packets

    Whether to capture Reset packets.

    Log DIAGNOSTIC Packets

    Whether to capture Diagnostic packets.

    Log RESTART Packets

    Whether to capture Restart packets.

    Log ERROR Packets

    Whether to capture Error packets.

    Log IGNORED Packets

    Whether to capture Ignored packets.

    Enable capture of Packet contents

    Whether to capture Packet contents.

    Enable line control diagnostics

    Whether to enable line control diagnostics.

    When you have finished

    Choose appropriate entries for the fields. Press F12 to return to panel 1 of the trace facilities, then press F10 to save the changes.


    Call nicknames panel

    You use this panel to define "call nicknames". These are your private names for external X.25 users. You input each nickname together with the user's NUA and the X.25 subsystem maintains a table linking the nickname with the user's NUA.

    Figure 14. X.25 Call Nicknames panel

     *-----------------------------------------------------------------------------*
     | 4. Call Nicknames                                                           |
     *-----------------------------------------------------------------------------*
     | Enter data at [ ].  Use F5 and F6 to select item from displayed alternatives|
     |                                                                             |
     |                                                                             |
     |  Call Nickname                            [NAME    ]                        |
     |  Description                              [                                ]|
     |                                                                             |
     |  Link Profile Name                        [LINK    ]                        |
     |                                                                             |
     |  Address                                  [               ]                 |
     |                                                                             |
     |  Address Extension                        [                                ]|
     |                                                                             |
     |  Request reverse charging                  NO                               |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F4=List Call Nicknames  F7=Backward             |
     | F10=Check and File  ^V=Move Selection Cursor                                |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Call Nickname

    Alphanumeric "nickname" to identify a remote user. This must be a maximum of eight characters, the first of which has to be alphabetic.

    Description

    A maximum of 32 characters of any text you want to enter.

    Link Profile Name

    Alphanumeric link name to specify the link over which a call is to be made.

    Address

    The address of the remote X.25 user, in the form appropriate to your network.

    Address Extension

    The address extension of the remote X.25 user. This is only used on the CCITT 1984 recommendation and may not be required for your system.

    Request reverse charging

    Causes reverse charging to be requested.

    When you have finished

    After you have keyed in a "nickname" entry for a remote X.25 user, press F10 to record the entry on file. (To see the current list of entries, press F4.) When you have entered all the nicknames that you want, press F7 to return to the configuration main menu shown in topic reference #7.


    Incoming call routing panel

    The PS/2 may have several applications connected to the PSDN at the same time. When an incoming call is received, the IBM X.25 Co-Processor Support Program must decide which, if any, should get the call.

    To manage this, the IBM X.25 Co-Processor Support Program maintains a routing table. This lists calls a local user-application is prepared to receive. When an incoming call is received, a routing procedure compares information about the sender (which it gets from the Incoming Call packet) and tries to match it with information provided by one of the potential receivers (a local user-application). If the match is successful, the call can be routed to this application.

    Routing information is set up using the panel described in this section. The fields held in the routing table correspond with those you set up in each entry in the panel.

    You enter the routing information on the panel shown in Figure 15.

    Figure 15. Incoming Call Routing panel

     *-----------------------------------------------------------------------------*
     | 5. Incoming Call Routing                                                    |
     *-----------------------------------------------------------------------------*
     | Enter data at [ ].                                                          |
     |                                                                             |
     |                                                                             |
     |  Routing entry name                       [ROUTE   ]                        |
     |  Description                              [                                ]|
     |                                                                             |
     |  Link profile name                        [*       ]                        |
     |                                                                             |
     |  Called Address                           [*              ]                 |
     |  Called Address Extension                 [*                               ]|
     |                                                                             |
     |  Calling Address                          [*              ]                 |
     |  Calling Address Extension                [*                               ]|
     |                                                                             |
     |  Call User Data                           [*               ]                |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F4=List Call Routing Entries  F7=Backward       |
     | F10=Check and File  ^V=Move Selection Cursor                                |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Routing entry name

    Eight-character name used to identify this routing table entry.

    Description

    A maximum of 32 characters of any text that you want to enter.

    Link profile name

    Name given to a link profile at configuration time. Only calls on this link are matched when this routing entry is used.

    Called Address

    The address of the local user in the form appropriate to your network.

    Called Address Extension

    Extension address of the local user (this is only significant in X.25 CCITT 1984 protocol).

    Calling Address

    The address of the caller in the form appropriate to your network.

    Calling Address Extension

    Extension address of the caller (only significant in X.25 CCITT 1984 protocol).

    Call User Data

    The contents of the Call User Data field in the Incoming Call packet, entered as hexadecimal digits.

    Note: Instead of specifying fields in full you can use global file-name characters in field specifications. They have meanings similar to their use when specifying file names in DOS:

    *
    assume all remaining characters match

    ?
    assume individual characters represented by ? match.
    You can enter global file-name characters in any of the input fields after the first. A "catch-all" entry in the table would consist of entries composed of single asterisks for all fields after the routing-entry name.

    When you have finished

    After you have keyed in an entry for each of your routing options (you need at least one entry in this table, which could be the "catch-all" mentioned above), record the entry by pressing F10. Do this for every routing option that you want. To see a list of current entries, press F4.

    When all the entries have been saved, return to the configuration main menu shown in topic reference #7 by pressing F7.

    Note: See topic reference #15 if you are configuring for another PS/2.


    Initializing the IBM X.25 Co-Processor Support Program

    (Ref #16.)

    About this Topic

    This topic describes how to initialize your PS/2 with the IBM X.25 Co-Processor Support Program before use. You must perform initialization every time you load DOS before you can run any X.25 application.

    You can only initialize the IBM X.25 Co-Processor Support Program on a PS/2 with at least one IBM X.25 Interface Co-Processor/2 adapter installed. Also, at least one link must have been configured. The link profile (.PRF) files that you created during configuration must be accessible in the current directory or in a directory specified in the PATH parameter in the X.25 parameter file (see "X.25 parameter file").

    Initialization loads the API of the IBM X.25 Co-Processor Support Program into the memory of the PS/2. It also loads the IBM X.25 Interface Co-Processor/2 adapter with the X.25 protocol code and with information contained in the link profile (.PRF) file. To do this it needs the file ICALOAD.COM (the standard loader of the DOS support utilities). This file is part of Realtime Interface Co-Processor DOS Support Package (see "Prerequisites").

    Links without an active link profile file are not recognized by the IBM X.25 Co-Processor Support Program, so cannot be initialized.

    The IBM X.25 Co-Processor Support Program stays resident in the memory of the PS/2 so you can run one or more applications that use the IBM X.25 Co-Processor Support Program API. You can also run other DOS applications, but be aware that large applications may not fit into the memory that is left.

    Warning!
    Applications that use the X.25 API, and any resident utility programs that were loaded after the IBM X.25 Co-Processor Support Program was loaded, are removed from memory when the IBM X.25 Co-Processor Support Program is stopped. The system is left how it was before the IBM X.25 Co-Processor Support Program was originally loaded; X.25 applications and resident utility programs have to be initialized before they can be used again.

    You should, therefore, load any resident utility programs before the IBM X.25 Co-Processor Support Program is loaded if you want to keep them in memory.

    X25 command

    The X25 command is used to do the initialization. (You can put this X25 command in your AUTOEXEC.BAT file if you want it to be executed each time DOS is loaded.) You use it with or without an X.25 parameter file name as follows:

         X25
    
    or
         X25 X.25 parameter file name
    
    For general help information, you must enter:
         X25 X.25 HELP
    
    You can use the X25 command without specifying an X.25 parameter file name or without specifying every possible parameter in the file. Where you do not specify a parameter, the system uses the default values that are described in the sections in "X.25 parameter file".

    X.25 parameter file

    The X.25 parameter file holds parameters that are used by the IBM X.25 Co-Processor Support Program during initialization. The parameters are described here (in alphabetic order). Each parameter specification requires one line in the file. You can create and edit this file using a standard DOS editor.

    CONnect, AUTOconnect, NOCONnect (default)

    If you specify CONnect, levels one and two of X.25 are automatically enabled (the link is connected) at initialization. If you specify AUTO the link is connected whenever an application makes, or listens for, a call. If you specify NOCON, or do not use this option, you have to connect the link later. (You can do this using link manager described in "Using the supplied facilities".)

    Note: You can only select CONnect or AUTOconnect if you are using the supplied management facilities. That is, with the HOTkey not set to NULL.

    EP_TICKS <number of ticks per episode>

    The larger the episode ticks value, the longer the foreground task is preempted by background tasks. High values give better API (and background task) performance at the expense of the foreground task. The default value is 5 (in eighteenths of a second).

    HOTkey <key>

    This parameter lets you define a "hotkey". When you press this hotkey during an application, the main link-management panel "pops-up" on the display (see "Using the supplied facilities").

    This can be a control alpha key or an alternative alpha key. The syntax for <key> is, for example, Cntl-X, or Alt-Z. The default hotkey is NULL.

    If you want to disable the supplied management functions (because you have supplied an alternative management application) use a <key> value of NULL.

    MEMory <size in kilobytes>

    This parameter specifies the memory pool to be reserved for use internally by the IBM X.25 Co-Processor Support Program. The default value is 32 kilobytes.

    NOLOGO

    The IBM logo panel is normally displayed at the start of initialization. The user has to press Enter to continue. Use this parameter if you do not want the IBM logo panel to be displayed.

    Note: The IBM logo panel includes the IBM Copyright Notice as well as the IBM logo. If you decide not to display the IBM logo panel, it is a condition that you insert the IBM Copyright Notice in the appropriate panel that is displayed. For example, on your own logo panel or where you display your own copyright notice.

    OPTions <filename 0>, <filename 1> ... <filename n>

    This parameter lets you use link parameter (.PRF) files, previously created using the configurator (on the current computer, or on another computer and copied). These link parameter files are used during initialization, replacing the ones allocated in configuration.

    The file names must be in the form xxxxxxxx.PRF, where xxxxxxxx is the link name (up to 8 characters). (If you omit the extension, .PRF is assumed.) The files must be in the directory specified in the PATH parameter, if used, otherwise they must be in the current directory.

    Filename 0 is loaded as the options link parameter file for logical card 0, file name 1 for logical card 1, and so on. The default link-parameter files names are those designated during configuration on the current computer.

    PATH <DOS path>

    This parameter lets you specify a path to a directory in which all required files are to be found, and into which any files produced by applications are placed. The default path is to the current directory, from which the X25 command is being executed. See also OUTput <DOS path>.

    OUTput <DOS path>

    If the OUT parameter is specified, the output from the API (for TRACE/Error Log for example) uses this path.

    If the OUT parameter is not specified, the output uses the path specified in the PATH parameter.

    STACK <size in kilobytes>

    This parameter lets you specify the stack size. (The size quoted is a total for all X.25 applications you are loading.) The default value is 2 kilobytes.

    TEXT <file name>

    The IBM X.25 Co-Processor Support Program uses a text file GQK?????.TXT to pick up text to appear on panels and in error messages. The file supplied is GQKENGLI.TXT.

    TT_PERIOD <timer tick period>

    The smaller the timer tick period, the more often the supervisor tries to restart tasks. Small values give a better API performance at the expense of foreground tasks. The default value is 2 (in eighteenths of a second).

    X25 (default), X25/29, X28, X25/28, X25/29/28

    This parameter lets you specify which of the possible combinations of API code you want to be loaded at initialization. You cannot run any applications without having the X.25 or X.28 API code present but if you load unnecessary APIs you restrict the amount of memory available for your applications.

    Example

    An example of an X.25 parameter file is shown below:

    CON
    X25/28
    MEM 20
    HOT Alt-S
    NOLOGO
    

    Loading and running applications

    Your X.25 applications can be run in one of two ways; you must know which way the application is designed to run before you can load it:

    1. Background applications. These applications run in a different way from regular DOS applications. When the application is loaded and initialized, it runs in background mode. You can then run other DOS applications (depending on the amount of space left in memory) while your X.25 application is running. The IBM X.25 Co-Processor Support Program lets you run several background applications at the same time.

    2. Regular DOS applications. These applications run in foreground mode, the same as any other DOS application. You cannot run other applications until the current one has ended.
    If your PS/2 has sufficient memory, you can run an X.25 application in foreground with one or more background applications. (See the IBM X.25 Co-Processor Support Program: Programmer's Reference for details of background and foreground processing.)

    To run a background application, you must enter:

        X25 LOAD application name
    
    The application name is the name of the X.25, X.28, or X.29 application. You can load up to 13 tasks into memory at the same time, using consecutive X25 LOAD commands, but the number is likely to be limited by the DOS memory limit.

    Note: An application can consist of more than one task.

    The IBM X.25 Co-Processor Support Program must have previously been initialized, as described in topic reference #16.

    Formatting the error log

    The program produces an error log that reports on the performance of the API, a new one overwriting the previous one whenever the X.25 subsystem is initialized. This file (GQK.ERR) is in a hexadecimal dump format. To format the dump into readable text, issue this command:

        X25 REPort <output file name>
    

    Dumping the IBM X.25 Interface Co-Processor/2 adapters

    When an error occurs with the API, a dump of the user buffers can be taken from one or more IBM X.25 Interface Co-Processor/2 adapters. The command to do this is:

        X25 DUMP
    
    This command invokes the DUMP.COM file that is supported by the Realtime Interface Co-Processor DOS Support Package. See the Realtime Interface Co-Processor DOS Support Package manuals for details.

    Capturing display messages from applications

    When debugging foreground applications, it can be useful to present the resultant messages on your display. However, when several tasks are issuing asynchronous messages, their interpretation can be confusing. You can intercept display messages and copy them onto disk by issuing this X.25 command:

      X25 REDirect [/o<stdout filename>] [/e<stderr filename>]
    
    Note: stdout and stderr are two DOS streams that direct data to the display.

    Messages that are sent to the display by way of stdout are intercepted by a memory-resident utility that copies them to the file. Similarly, messages that are sent to stderr are copied to the file. If you make the filenames the same, all display messages are duplicated in the same file.

    The capture of display messages for either file can be turned off by reissuing the command and leaving the file name blank.

    You can stop the capture of display messages by issuing this X.25 command:

      X25 REDirect /r
    
    Note: Other memory-resident applications that are loaded after this utility may have to be removed from memory to avoid possible conflicts within the system.
      /S Option
    
    Where /S+ switches the display on and /S- switches the display off.

    Terminating the IBM X.25 Co-Processor Support Program

    You stop the IBM X.25 Co-Processor Support Program by issuing the following form of the X25 command:

        X25 TERMinate
    
    Warning!
    Applications that use the X.25 API, and any resident utility programs that were loaded after IBM X.25 Co-Processor Support Program was loaded, are removed from memory when IBM X.25 Co-Processor Support Program is stopped. The system is left how it was before IBM X.25 Co-Processor Support Program was originally loaded; X.25 applications and resident utility programs have to be initialized before they can be used again.

    You should, therefore, load any resident utility programs before the IBM X.25 Co-Processor Support Program is loaded if you want to keep them in memory.


    Using the supplied facilities


    About this Topic

    The IBM X.25 Co-Processor Support Program provides two tasks that are normally made resident during initialization; these tasks provide facilities to manage the system. You need not use these supplied tasks: you can write applications of your own that provide similar facilities. Alternatively, you could build similar facilities into applications that you write.

    The facilities can be split into:

    Link management
    This controls the link to the X.25 network.

    Event management
    This deals with unexpected events, not normally handled by applications.

    Link management

    Link management lets you connect (activate) and disconnect (deactivate) links to an X.25 network. Link management also lets you trace operations on a link.

    You can perform link management using the panels provided by the supplied link-management task. These are described in the following sections.

    You can use this set of four panels only after the IBM X.25 Co-Processor Support Program has been initialized (see "Initializing the IBM X.25 Co-Processor Support Program"). The main panel "pops up" when you press a hotkey. The default hotkey is NULL but you can define another key to do the same job (see "X.25 parameter file").

    You can use a hotkey at the DOS prompt or when you are running a DOS application (not necessarily an X.25 DOS application). Link-management panels "pop-up" over current panels and go away when you press the Esc key.

    Notes:

    1. You can change the default hotkey only when using a combination of X.25, X.28, and X.29. It cannot be changed when using X.25 alone.

    2. If you press the hotkey when an application is running, the link-management panel may not appear if keys are being used in a nonstandard way. If this happens, terminate the application and press the hotkey when you see the DOS prompt.

    3. Panels of applications that use graphics are not restored when the "pop up" panel goes away. Do not, therefore, press the hotkey under such circumstances.
    The structure and interconnections of the link-management panels are shown in Figure 16.

    Figure 16. Link-management panels

                        +-----------------------+
                        |     Main Link         |
                        |   Management Menu     |
                        +-----------+-----------+
                                    |
               +--------------------+--------------------+
               |                                         |
      +--------+--------+                       +--------+--------+
      | Set/Reset Trace |                       | Set Link Mode   |
      |    Facility     |                       |                 |
      +-----------------+                       +-----------------+
    

    Function keys

    Most function keys have the same meanings as in the configuration panels (see "Function key assignment"). The exception is F10, which on these panels is the action key. F10 connects or disconnects the link, according to the panel you are in.

    Help information

    As with the configuration panels, help panels give general information about the fields on the panel and on options available for data entry. You can see the help panels by pressing F1.

    Link-management main-menu panel

    The link-management main menu is shown in Figure 17 and gives you a list of secondary panels that you use to set parameters for the link management of the system.

    Figure 17. Link-management main-menu panel

     *-----------------------------------------------------------------------------*
     |  X.25 Co-Processor Support: Manager - Main Menu                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     |  Select option and enter.                                                   |
     |                                                                             |
     |                                                                             |
     |   1. Set/Reset Trace Facilities                                             |
     |   2. Link Management (Start/Stop/Auto)                                      |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  ^V=Move Selection Cursor                        |
     |                                                                             |
     *-----------------------------------------------------------------------------*
    
    You make selections from this panel in the same way as from the configuration main menu: The selected secondary panel then appears.

    Trace facilities panel

    This panel, which is shown in Figure 18, lets you start and stop the tracing of packets and frames. Using it, the results of an operation initiated in an application can be traced through to the network.

    During configuration, you must set up details of the frames and packets you want to be traced. (This is described in "Trace facilities panel".)

    The system puts the file of trace data into the directory specified in the PATH parameter in the X.25 parameter file, if you have used one. If you have not specified a path, the file is put into the current directory. The file name is the link-profile name followed by an extension of .TRC. You can format and display the trace file data using a standard DOS editor.

    Figure 18. X.25 Trace Facilities panel

     *-----------------------------------------------------------------------------*
     |  1 Trace Facilities                                                         |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | Use F5 or F6 to select item from displayed alternatives                     |
     |                                                                             |
     |                                                                             |
     |   Trace entry name                            [TRACE   ]                    |
     |                                                                             |
     |   Trace data between Adapter and Network      NO                            |
     |   Capture current X.25 Statistics             NO                            |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F7=Backward                                     |
     | F10=Complete Trace  ^V=Move Selection Cursor                                |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Trace entry name

    This is an eight-character name that defines a trace entry.

    Trace data between Adapter and Network

    Specifies whether tracing is to be performed by the IBM X.25 Interface Co-Processor/2 adapter protocol code.

    Capture current X.25 Statistics

    Specifies whether IBM X.25 Interface Co-Processor/2 adapter-code statistics are to be captured.

    When you have finished

    After you have keyed in, or chosen, the appropriate options, start or stop the trace by pressing F10.

    Link-management panel

    This panel lets you connect or disconnect one or more X.25 links.

    Figure 19. X.25 Link Management panel

     *-----------------------------------------------------------------------------*
     |  2 Link Management                                                          |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | Use F5 or F6 to select item from displayed alternatives                     |
     |                                                                             |
     |                                                                             |
     |   Link Profile Name                           All                           |
     |                                                                             |
     |   Link Mode                                   Connect                       |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ENTER  ESC=Cancel  F1=Help  F7=Backward                                     |
     | F10=Complete Option ^V=Move Selection Cursor                                |
     *-----------------------------------------------------------------------------*
    
    The option fields have the following meanings:

    Link Profile Name

    The name of the link profile for the adapter whose Link Mode you want to change. You can choose from:

    Link mode

    The state into which you want the link to be placed. The three options for each link are:

    1. Connect. The link is connected at level 2 (default).

    2. Disconnect. The link is disconnected at level 2.

    3. Automatic. The link is connected at level 2 when a user-application requests that a call be made, and disconnected, when the last user call is cleared.

    When you have finished

    After you have selected the link and link-management option you require, press F10.


    Event management

    The supplied event manager handles link "events" that are not handled by normal user-written applications.

    The event manager deals with:

    Link-error panel

    If one or more links report errors, the event manager displays the error type and attempts to disconnect the links in an orderly manner. The link-error panel is shown in Figure 20.

    Figure 20. X.25 Link-Error panel

     *-----------------------------------------------------------------------------*
     |  X.25 Link Error                                                            |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     |                                                                             |
     |  Link name <link profile name>                                              |
     |                                                                             |
     |  Link error <link error>                                                    |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ESC=Cancel                                                                  |
     |                                                                             |
     *-----------------------------------------------------------------------------*
    
    The meanings of the fields that report the error are as follows:

    Link name

    This is the link-profile name assigned to this link during configuration.

    Link error

    The error is one of the following:

    What you must do

    If you have an error on the link, do the following:

    Incoming-call-received panel

    A call has come in that is not being "listened for" (see IBM X.25 Co-Processor Support Program: Programmer's Reference for an explanation of this term). The event manager displays the call details and offers you several alternatives.

    Details of the call are displayed on the panel shown in Figure 21. This panel "pops up" whenever an unsolicited incoming call is received.

    Figure 21. X.25 Incoming-Call-Received panel

     *-----------------------------------------------------------------------------*
     |  Incoming Call Received                                                     |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     |  Use F5 or F6 to select item from displayed alternatives                    |
     |                                                                             |
     |                                                                             |
     |  Link name                      <link profile name>                         |
     |                                                                             |
     |  Called Address                 <called address>                            |
     |  Calling Address                <calling address>                           |
     |                                                                             |
     |  Call user data field           <call user data>                            |
     |                                                                             |
     |  Action Required for call       Do nothing                                  |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     |                                                                             |
     *-----------------------------------------------------------------------------*
     | ESC=Cancel (Do nothing)  F1=Help  F10=Complete Action                       |
     |                                                                             |
     *-----------------------------------------------------------------------------*
    
    The meanings of the fields on the panel are as follows:

    Link name

    This is the name you assigned to this link during configuration.

    Called Address

    The network user address NUA of the person being called, as taken from the Incoming Call packet.

    Calling Address

    The network user address NUA of the caller, as taken from the Incoming Call packet.

    Call user data field

    The contents of the start of the Call User Data field in the Incoming Call packet.

    Action required for call

    The choice of action is:

    You need to agree with the person responsible for the application what action to take should the unsolicited calls panel appear.

    Dealing with problems


    About this Topic

    You may get problems during configuration and initialization. This topic explains how errors are reported to you and what you should do.


    Configuration errors

    These errors may be detected by the X.25 subsystem while you are configuring the link. All are preceded by X.25 ERROR (Cnnn): where nnn is the error number shown against the error text in the listing below.

    In all cases, when you have corrected the cause of the error, you must restart configuration by typing:

         X25 CONFigure 
    

    General errors

    C001: Not enough memory

    Meaning: The X.25 subsystem does not have enough free memory available for it to run.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    C002: Unable to Initialize windows

    Meaning: The X.25 subsystem cannot create a panel to continue the configuration because of lack of memory.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    C003: Error while making window

    Meaning: The X.25 subsystem cannot create a panel to continue configuration because of lack of memory.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    Problems with files

    Note: There may be a DOS error code reported with these errors. Consult the DOS documentation for an explanation of the DOS error code.

    C004: Error reading text (.TXT) file

    Meaning: The system cannot find GQKENGLI.TXT in the current directory or in the PATH if you have specified a path.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    C005: Error while opening Link file

    Meaning: A Link file exists, but the subsystem cannot open it, probably because it has been corrupted.

    Action: Erase the Link file and reconfigure the Link.

    C006: Error while writing Link file

    Meaning: The subsystem is unable to write the Link file because of insufficient fixed-disk space.

    Action: Delete some unwanted files from the fixed disk so as to provide the necessary fixed-disk space.

    C007: Error while opening Names file

    Meaning: A Names file (called NAMES.X25) exists, but the subsystem cannot open it, probably because it has been corrupted.

    Action: Erase the Names file and reconfigure.

    C008: Error while opening Route file

    Meaning: A Route file (called ROUTE.X25) exists, but the subsystem cannot open it, probably because it has been corrupted.

    Action: Erase the Route file and reconfigure.

    C009: Error while opening Trace file

    Meaning: A Trace file (called TRACE.X25) exists but the subsystem cannot open it, probably because it has been corrupted.

    Action: Erase the Trace file and reconfigure.

    C010: Error while opening Internal file

    Meaning: An internal file exists but the subsystem cannot open it, probably because it has been corrupted.

    Action: Reconfigure the Link.

    C011: Error while writing file

    Meaning: The subsystem is unable to write the file because of insufficient fixed-disk space.

    Action: Delete some unwanted files from the fixed disk so as to provide the necessary fixed-disk space.


    Initialization errors

    These errors are detected by the X.25 subsystem while it is doing X.25 initialization. When errors are reported on the screen, they are all preceded by X.25 ERROR (Innn): where nnn is the error number, shown against the error text in the listing below.

    In all cases, when you have corrected the cause of the error, you must restart initialization by typing:

         X25 <filename>
    
    where filename is the name of the X.25 parameter file.

    If the system still does not work, the code has probably been corrupted and you need to reinstall the IBM X.25 Co-Processor Support Program.

    General errors

    I001: Not a PS/2 machine, or no adapters present

    Meaning: You can only initialize the X.25 subsystem on a PS/2 with a Micro Channel. The PS/2 must contain at least one IBM X.25 Interface Co-Processor/2 adapter and you must have configured a link to the network.

    Action: Check that the adapter has been installed and that there is a configuration parameter file (extension .PRF) in the current directory or in the PATH if you have specified one.

    I002: Not DOS level 3.3 or above

    Meaning: The initialization procedure checks that the version of DOS in the PS/2 is 3.3 or above.

    Action: Check your version of DOS (for example, by typing ver at the DOS prompt) and upgrade DOS if necessary.

    I003: Unable to initialize windows

    Meaning: The X.25 subsystem cannot create a window to continue the initialization, probably because the code has been corrupted.

    Action: Reinstall the IBM X.25 Co-Processor Support Program.

    I004: Error while making window

    Meaning: The X.25 subsystem cannot create a window to continue the initialization because of lack of memory.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    I005: Unable to load X.25 adapters

    Meaning: The system cannot load the IBM X.25 Interface Co-Processor/2 adapter with the X.25 protocol code (from GQKPTCOL.EXE). The reason is lack of memory in the PS/2.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    I006: Not enough memory

    Meaning: The X.25 subsystem does not have enough free memory available for it to run.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    I007: This file cannot be run stand alone

    Meaning: You are trying to run one of the initialization programs (probably GQKINIT.EXE or GQK???.EXE) on its own, without using the X25 command. This is not allowed.

    Action: Use the X25 command to initialize the subsystem.

    I008: The API is already installed

    Meaning: The application program interface is already installed.

    Action: None.

    Files missing or corrupt

    I009: Unable to open parameter file

    Meaning: You have specified a parameter file in an X25 command but the file does not exist in the current directory, or in the path included with the filename, if one is present.

    Action: Check the file name (and any path you have used) for the X.25 parameter file.

    I010: Unable to access text (GQK?????.TXT) file

    Meaning: The system cannot find GQKENGLI.TXT in the current directory or in the PATH if you have specified a path.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    I011: Unable to find the Link Profile (.PRF) file

    Meaning: The subsystem cannot find the required .PRF files in the current directory, or in the PATH if you specified a path. One .PRF file is produced for each configuration of a link. You should have done one of the following:

    Action: Check the PATH and OPTions lines in your parameter file. If these are correct and you configured the links on another machine recopy the .PRF files. If you configured the links on the current machine, repeat the configuration. Reconfigure the links on the current machine.

    I012: Link profile (.PRF) file corrupt

    Meaning: One or more .PRF files exist, but have been corrupted. (See previous error for explanation of .PRF files.)

    Action: Check the PATH and OPTions lines in your parameter file. If necessary, reconfigure the links.

    I013: Unable to access X.25 adapters (ADAPTERS.X25) file

    Meaning: The configuration process produces one internal file in the PS/2. The subsystem cannot find this internal file in the current directory or in the PATH if you specified one.

    Action: Either reconfigure the link on the target machine or use the OPTions parameter specifying files which have been produced during configuration on another machine.

    I014: Unable to find ICAAIM.COM

    Meaning: This file contains the Realtime Control Microcode (RCM) for the IBM X.25 Interface Co-Processor/2 adapter (The file is supplied with the adapter.) The subsystem cannot find the file in the default or stated directory.

    Action: Ensure that the file is in the default directory or in the directory specified in the PATH statement.

    I015: Unable to access X.25 defaults (GQKPTCOL.DEF) file

    Meaning: These defaults are in the file GQKPTCOL.DEF, supplied as part of the IBM X.25 Co-Processor Support Program. The subsystem cannot find this file in the current directory or in the PATH, if you specified one.

    Action: Check the PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    I016: Unable to run interrupt handler

    Meaning: The interrupt handler is contained in the file ICAINTH.COM (supplied as part of Realtime Interface Co-Processor DOS Support Package). The subsystem cannot find this file in the default or stated directory.

    Action: Ensure that the file is in the default directory or in the directory specified in the PATH statement.

    I017: Unable to find GQKCONF.EXE

    Meaning: The program GQKCONF.EXE, supplied with the IBM X.25 Co-Processor Support Program is not in the current directory or in the PATH, if you have specified one.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    I018: Unable to find GQKPTCOL.EXE

    Meaning: The file GQKPTCOL.EXE contains the X.25 protocol code that the subsystem must load onto the IBM X.25 Interface Co-Processor/2 adapter. The subsystem cannot find the file in the current directory or in the PATH, if you specified one. The file is supplied as part of the IBM X.25 Co-Processor Support Program.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    I019: Unable to find X.25 Internal file

    Meaning: This internal file is used to pass data between various processes that perform the initialization. The most likely reason for the subsystem not being able to find this file is because it was not created due to lack of fixed-disk space.

    Action: Erase some unwanted files from the fixed disk to provide more space.

    I020: Unable to find GQKINIT.EXE file

    Meaning: This is one of the files that performs the initialization. It is provided as part of the IBM X.25 Co-Processor Support Program. The subsystem cannot find this file in the current directory or in the PATH specified.

    Action: Check the PATH and OPTions lines in your parameter file. If necessary, reconfigure the links.

    I021: Unable to find the API executable file

    Meaning: The subsystem cannot find the IBM X.25 Co-Processor Support Program file containing the API code in the current directory or in the PATH specified.

    Action: Check the PATH and OPTions lines in your parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    I022: Unable to access interrupt handler parameter (ICAPARM.PRM) file

    Meaning: This parameter file must be present if any Realtime Interface Co-Processor adapters are present in the PS/2 (with the IBM X.25 Interface Co-Processor/2 adapters). The file is supplied with the Realtime Interface Co-Processor adapter.

    Action: Load the missing file.

    I023: The ICAPARM.PRM file contains incorrect X.25 adapter information.

    Meaning: One of the entries in the ICAPARM.PRM file has an I/O address different from the adapter to which it refers.

    Action: Refer to the Realtime Interface Co-Processor adapter documentation.

    I024: Unable to access adapter dump (DUMP.COM) file

    Meaning: The program DUMP.COM, supplied with the Realtime Interface Co-Processor DOS Support Package is not in the current directory or in the PATH, if you have specified one.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    I025: Unable to find GQKREP.EXE file

    Meaning: The program GQKREP.EXE, supplied with the IBM X.25 Co-Processor Support Program is not in the current directory or in the PATH, if you have specified one.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.

    Parameter file contents

    The following messages refer to problems with the X.25 parameter file that you have specified in the X25 command line:

         X25 filename
    
    I026: Incorrect parameter specified

    Meaning: A parameter you have specified in the X.25 parameter file is invalid.

    Action: See "Initializing the IBM X.25 Co-Processor Support Program" for a description of the possible parameters.

    I027: No text name given

    Meaning: You have used the TEXT parameter without specifying a text filename.

    Action: Insert a text filename in the TEXT parameter line.

    I028: No HOTkey value given

    Meaning: You have used the parameter HOTkey without specifying what the hotkey should be.

    Action: Insert the value of HOTkey (for example, ALT-Z) into the HOTkey parameter line.

    I029: Incorrect key code

    Meaning: You have specified an invalid HOTkey value. (Valid values are ALT-x or CNTL-x where x is an alpha character A through Z. Uppercase and lowercase values are regarded as being identical.)

    Action: Correct the HOTkey parameter that you have specified.

    I030: No path given

    Meaning: You have used the PATH parameter in the X.25 parameter file without specifying what the path is.

    Action: Insert a path in the PATH parameter line.

    I031: No memory size given

    Meaning: You have used the MEMory parameter without specifying a memory size.

    Action: Specify a valid memory size in the MEM parameter line.

    I032: Incorrect memory size given

    Meaning: You have specified a memory size, using the MEMory parameter but the value is not numeric or of invalid size. The value must be 1 kilobyte through 64 kilobytes.

    Action: Correct the specified memory size in the MEMory parameter line.

    I033: No option names given

    Meaning: You have used the OPTions parameter without specifying at least one filename of options data. (Up to 8 filenames are allowed.)

    Action: Insert a filename of options in the OPTions parameter line.

    I034: No stack size given

    Meaning: You have used the STACK parameter in the parameter file but not quoted a stack size.

    Action: Insert a valid stack size in the STACK parameter line.

    I035: Incorrect stack size given

    Meaning: You have used the STACK parameter in the parameter file but the stack size you have quoted is either not numeric or outside the allowed limits (1 kilobyte through 64 kilobytes).

    Action: Correct the stack-size value in the STACK parameter line.

    Loading an application

    I036: API inoperable or not loaded

    Meaning: You have requested an application to be loaded (using X25 load) before doing the initialization. Initialization must be done first.

    Action: Perform initialization using X25 .

    I037: Unable to find file to load

    Meaning: You have specified a filename using X25 load which the subsystem cannot find in the current directory or in the PATH specified.

    Action: Check the PATH and OPTions lines in your parameter file and that the file exists.

    I038: File must be of .EXE type

    Meaning: You are using X25 load to load a file that is not an executable program.

    Action: Correct the file you are loading (it must be of .EXE type).

    I039: Could not load file

    Meaning: You have specified a filename using X25 load. Although the subsystem has found the file, and the file is of the correct type, it cannot be loaded for some reason, probably because there is not enough memory.

    Action: Make more memory available by discarding any nonessential memory-resident code.


    Management errors

    These errors are detected by the X.25 subsystem while it is doing Link management or Event management. All are preceded by X.25 ERROR and an error number in the form Ennn, as shown below.

    All errors require that you reinitialize the X.25 subsystem.

    General errors

    E001: Unable to initialize windows

    Meaning: The X.25 subsystem cannot create a window required in management, probably because the code has been corrupted.

    Action: Reinstall the IBM X.25 Co-Processor Support Program.

    E002: Error while making window

    Meaning: The X.25 subsystem cannot create a window to continue management because of lack of memory.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    E003: This file cannot be run stand alone

    Meaning: You are trying to run one of the link- or event management programs on its own, without using the X25 command. This is not allowed.

    Action: Use the management menus as described in "Using the supplied facilities".

    E004: Unable to start the supervisor

    Meaning: The supervisor part of the X.25 subsystem code has become corrupted in some way.

    Action: Reinstall the IBM X.25 Co-Processor Support Program.

    E005: Not enough memory

    Meaning: The X.25 subsystem does not have enough free memory for it to run.

    Action: Make more memory available by discarding any nonessential memory-resident code.

    E006: Unable to start the memory manager

    Meaning: The subsystem has not enough memory available. You may have asked for too little memory in the MEMory parameter.

    Action: Use the MEMory parameter in initialization to increase the memory available.

    E007: Unable to start the queue manager

    Meaning: The queue manager part of the X.25 subsystem code has been corrupted in some way.

    Action: Reinstall the IBM X.25 Co-Processor Support Program.

    E008: Unable to start the API

    Meaning: The API part of the X.25 subsystem code has been corrupted in some way.

    Action: Reinstall the IBM X.25 Co-Processor Support Program.

    E009: Unable to start the Link Manager

    Meaning: There is not enough memory available to run the Link Manager.

    Action: Increase the memory available by using the MEMory parameter.

    E010: API Verb Call failed

    Meaning: The API part of the X.25 subsystem code has been corrupted in some way.

    Action: Reinitialize the subsystem. If this is not successful, reinstall the IBM X.25 Co-Processor Support Program.

    E011: Unable to start the event manager

    Meaning: There is not enough memory available to run the event manager.

    Action: Increase the memory available by using the MEMory parameter.

    E012: Unable to access text (GQK?????.TXT) file

    Meaning: The system cannot find GQKENGLI.TXT in the current directory or in the PATH if you have specified a path.

    Action: Check your PATH parameter in the parameter file. If necessary, reinstall the IBM X.25 Co-Processor Support Program.


    Appendix A. Parameter checklist

    Make a copy of the following topics fill in the "parameter for your network" field with your own information, and use the copies as a quick reference when you:

    1. Plan the configuration of your network.

    2. Carry out the configuration of your network.

    3. Change the configuration of your network.

    X.25 link profile

    See topic reference #8 for details of this panel.

    +===========================+====================+===========================+
    | Name of field             | Parameter range    | Parameter for your        |
    |                           |                    | network                   |
    +===========================+====================+===========================+
    | Link-profile name         | N/A                |                           |
    +---------------------------+--------------------+---------------------------+
    | Description               | N/A                |                           |
    |                           |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Electrical interface      | X.21               |                           |
    |                           | X.21 bis/V.24      |                           |
    |                           | X.21 bis/V.35      |                           |
    +---------------------------+--------------------+---------------------------+
    | CCITT compliance          | 1980               |                           |
    |                           | 1984               |                           |
    +---------------------------+--------------------+---------------------------+
    | Logical DTE/DCE           | DCE                |                           |
    |                           | DTE                |                           |
    +---------------------------+--------------------+---------------------------+
    | Transpac VX32             | YES/NO             |                           |
    +---------------------------+--------------------+---------------------------+
    | Country code              | See topic          |                           |
    |                           | reference #9       |                           |
    +---------------------------+--------------------+---------------------------+
    

    X.25 link profile - frame parameters

    See topic reference #10 for details of this panel.
    +===========================+====================+===========================+
    | Name of field             | Parameter range    | Parameter for your own    |
    |                           |                    | network                   |
    +===========================+====================+===========================+
    | Window size               | Mod.8: 0 - 7       |                           |
    |                           | Mod.128: 0 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | Frame sequence modulus    | 8                  |                           |
    |                           | 128                |                           |
    +---------------------------+--------------------+---------------------------+
    | Retry time out (50 mS)    | 0 - 100            |                           |
    +---------------------------+--------------------+---------------------------+
    | Retry count (frames)      | 1 - 255            |                           |
    +---------------------------+--------------------+---------------------------+
    | Inoperational time out    | 1 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    

    X.25 link profile - packet parameters

    See topic reference #11 for details of this panel.

    +===========================+====================+===========================+
    | Name of field             | Parameter range    | Parameter for your own    |
    |                           |                    | network                   |
    +===========================+====================+===========================+
    | Number of PVCs            | 0 - 63             |                           |
    |                           |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Lowest PVC channel number | 0 - 4095           |                           |
    +---------------------------+--------------------+---------------------------+
    | Number of incoming only   | 0 - 250            |                           |
    | SVCs                      |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Lowest incoming only SVC  | 0 - 4095           |                           |
    | number                    |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Number of Bothway SVCs    | 0 - 250            |                           |
    +---------------------------+--------------------+---------------------------+
    | Lowest Bothway SVC number | 0 - 4095           |                           |
    +---------------------------+--------------------+---------------------------+
    | Number of Outgoing only   | 0 - 250            |                           |
    | SVCs                      |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Lowest Outgoing only SVC  | 0 - 4095           |                           |
    | number                    |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Packet sequence number    | 8                  |                           |
    | modulus                   | 128                |                           |
    +---------------------------+--------------------+---------------------------+
    

    X.25 link profile - packet time outs

    See topic reference #12 for details of this panel.

    +===========================+====================+===========================+
    | Name of field             | Parameter range    | Parameter for your        |
    |                           |                    | network                   |
    +===========================+====================+===========================+
    | Restart request time out  | 1 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Call request time out     | 1 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Reset request time out    | 1 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Clear request time out    | 1 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Acknowledgment time out   | 0 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Data packet time out      | 0 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Interrupt packet time out | 0 - 255            |                           |
    | (seconds)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Reset request retry count | 1 - 255            |                           |
    | (packets)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    | Clear request retry count | 1 - 255            |                           |
    | (packets)                 |                    |                           |
    +---------------------------+--------------------+---------------------------+
    

    X.25 link profile - SVC parameters

    See topic reference #13 for details of this panel.

    +===========================+====================+===========================+
    | Name of field             | Parameter range    | Parameter for your        |
    |                           |                    | network                   |
    +===========================+====================+===========================+
    | Default incoming packet   | 1980: 16 - 1024    |                           |
    | size (bytes)              | 1984: 16 - 4096    |                           |
    +---------------------------+--------------------+---------------------------+
    | Maximum incoming packet   | 1980: 16 - 1024    |                           |
    | size (bytes)              | 1984: 16 - 4096    |                           |
    +---------------------------+--------------------+---------------------------+
    | Default outgoing packet   | 1980: 16 - 1024    |                           |
    | size (bytes)              | 1984: 16 - 4096    |                           |
    +---------------------------+--------------------+---------------------------+
    | Maximum outgoing packet   | 1980: 16 - 1024    |                           |
    | size (bytes)              | 1984: 16 - 4096    |                           |
    +---------------------------+--------------------+---------------------------+
    | Default incoming window   | Mod.8: 1 - 7       |                           |
    | size (packets)            | Mod.128: 1 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | Maximum incoming window   | Mod.8: 1 - 7       |                           |
    | size (packets)            | Mod.128: 1 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | Default outgoing window   | Mod.8: 1 - 7       |                           |
    | size (packets)            | Mod.128: 1 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | Maximum outgoing window   | Mod.8: 1 - 7       |                           |
    | size (packets)            | Mod.128: 1 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | Maximum throughput class  | 75 bps             |                           |
    | (bits per second)         | 150 bps            |                           |
    |                           | 300 bps            |                           |
    |                           | 600 bps            |                           |
    |                           | 1200 bps           |                           |
    |                           | 2400 bps           |                           |
    |                           | 4800 bps           |                           |
    |                           | 9600 bps           |                           |
    |                           | 19200 bps          |                           |
    |                           | 48000 bps          |                           |
    +---------------------------+--------------------+---------------------------+
    

    X.25 link profile - PVC parameters

    See topic reference #14 for details of this panel.

    +===========================+====================+===========================+
    | Name of field             | Parameter range    | Parameter for your        |
    |                           |                    | network                   |
    +===========================+====================+===========================+
    | PVC number                | 0                  |                           |
    |                           | 63                 |                           |
    +---------------------------+--------------------+---------------------------+
    | Incoming packet size      | 1980: 0 - 1024     |                           |
    | (bytes)                   | 1984: 0 - 4096     |                           |
    +---------------------------+--------------------+---------------------------+
    | Outgoing packet size      | 1980: 0 - 1024     |                           |
    | (bytes)                   | 1984: 0 - 4096     |                           |
    +---------------------------+--------------------+---------------------------+
    | Incoming window size      | Mod.8: 1 - 7       |                           |
    | (packets)                 | Mod.128: 1 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | Outgoing window size      | Mod.8: 1 - 7       |                           |
    | (packets)                 | Mod.128: 1 - 127   |                           |
    +---------------------------+--------------------+---------------------------+
    | PVC Protocol              | X.25               |                           |
    |                           | SNA80              |                           |
    |                           | SNA84              |                           |
    +---------------------------+--------------------+---------------------------+
    

    Appendix B. Glossary

    This glossary includes definitions from:

    A

    adapter
    See communication adapter.

    API
    Application program interface.

    application program interface (API)
    The formally defined programming language interface which is between an IBM system control program or a licensed program and the user of the program.

    asynchronous data transfer
    A physical transfer of data to or from a device that occurs without a regular or predictable time relationship following the execution of an I/O request.

    B

    bis
    Describes a secondary recommendation that is an alternative to a primary recommendation.

    C

    CCITT
    Comite Consultatif International Telegraphique et Telephonique. The International Telegraph and Telephone Consultative Committee. An organization of common carriers and PTTs that recommends standards for the interconnection of communications equipment.

    closed user group
    A group of network subscribers that can communicate with one another, but whose access is normally barred to and from all other subscribers of the service. Many networks offer closed user groups with incoming and outgoing access allowed.

    communication adapter
    A circuit card with associated software that enables a processor, controller, or other device to be connected to a network.

    communications co-processor
    A microprocessor on an expansion board that supplements the operations of the processor in the system unit, enabling a computer to use communication services in parallel with other operations.

    configure
    To describe to a system the nature, number, and chief characteristics of its functional units, either hardware or software.

    D

    data circuit-terminating equipment (DCE)
    In a data station, the equipment that provides the signal conversion and coding between the data terminal equipment (DTE) and the line. (I)

    data link
    The assembly of parts of two data terminal equipment that are controlled by a link protocol, and the interconnecting data circuit, that enable data to be transferred from a data source to a data sink. (I)
    The interconnecting data circuit and the link protocol between two or more equipments; it does not include the data source or the data sink.

    data packet
    At the interface between a data terminal equipment (DTE) and a data circuit-terminating equipment (DCE), a packet used to transmit user data over a virtual circuit.

    data terminal equipment (DTE)
    That part of a data station that serves as a data source, data sink, or both. (I)

    DCE
    Data circuit-terminating equipment

    DCE clear confirmation packet
    A call supervision packet that a data circuit-terminating equipment (DCE) transmits to confirm that a call has been cleared.

    delivery confirmation bit (D-bit)
    A bit in the data-packet header that instructs the network to wait until delivery to the remote DTE has been confirmed before confirming delivery to the sending DTE. Usually, confirmation is returned to the sending DTE when its packets have been transmitted to the network.

    DTE
    Data terminal equipment.

    duplex
    Pertaining to communication in which data can be sent and received at the same time. Contrast with half-duplex.

    F

    frame
    The contiguous sequence of eight-bit bytes delimited by beginning and ending flags. Frames are used to perform control functions, data transfers, and transmission checking on the link.

    frame level
    See link level.

    H

    half-duplex
    In data communication, pertaining to transmission in only one direction at a time. Contrast with duplex.

    I

    incoming call packet
    A call supervision packet transmitted by a data circuit-terminating equipment (DCE) to inform a called data terminal equipment (DTE) that another DTE has requested a call.

    International Organization for Standardization (ISO)
    An organization of national standards bodies from various countries established to promote development of standards to facilitate international exchange of goods and services, and develop cooperation in intellectual, scientific, technological, and economic activity.

    ISO
    International Organization for Standardization.

    L

    LAP
    Link access procedures.

    LAPB
    Link access protocol-balanced.

    link
    In data communications, the combination of the physical medium of transmission, the protocol, and associated devices and programming; it is both logical and physical.

    link access procedures (LAP)
    The link level elements used for data interchange between data circuit-terminating equipment (DCE) and data terminal equipment (DTE) operating in user classes of service 8 to 11, as specified in CCITT Recommendation X.1.

    link access protocol-balanced
    A protocol used for accessing an X.25 network at the link level. LAPB is a duplex, asynchronous, symmetric protocol, used in point-to-point communication. It supersedes the earlier LAP protocol.

    link level
    A part of Recommendation X.25 that defines the link protocol used to get data into and out of the network across the full-duplex link connecting the subscriber's machine to the network node. LAP and LAPB are the link access protocols recommended by the CCITT.

    logical channel
    In packet mode operation, a sending channel, a receiving channel, or both used at the same time, established on a data link. Several logical channels can be established on the same data link by interleaving the transmission of packets.

    M

    modem (modulator/demodulator)
    See data circuit-terminating equipment.

    more data bit (M-bit)
    A bit in a data packet header that indicates the following packet contains logically related data.

    N

    network user address (NUA)
    Up to 15 decimal digits that serve to identify a data terminal equipment (DTE). The first four digits (digits 0 to 3) of an NUA are known as the data network identification code (DNIC); they identify the country and the service within the country. Digits 4 to 12 indicate the national number. The final two digits may be used for a subaddress.

    NUA
    Network user address.

    O

    octet
    A byte composed of eight binary elements. (I)

    optional network facilities
    Facilities a network user may request when establishing a virtual circuit.

    P

    packet
    In data communication, a sequence of binary digits, including data and control signals, that is transmitted and switched as a composite whole. (I)

    packet assembler/disassembler (PAD)
    An equipment used for connecting asynchronous (start/stop) devices to an X.25 network.

    packet level
    A part of CCITT Recommendation X.25 that defines the protocol for establishing logical connections between two DTEs and for transferring data on these connections.

    packet switching
    The process of routing and transferring data by means of addressed packets so that a channel is occupied only during the transmission of a packet. On completion of the transmission, the channel is made available for the transfer of other packets. (I)

    packet switching data network (PSDN)
    A communications network that uses packet switching as a means of transmitting data.

    PAD
    packet assembler/disassembler.

    PAD parameters
    A set of values that define the behavior of the PAD. They can be changed either by the remote DTE (using X.29 commands) or by the local asynchronous device (using X.28 commands).

    permanent virtual circuit (PVC)
    A virtual circuit that has a logical channel permanently assigned to it at each data terminal equipment (DTE). A call establishment protocol is not required. A permanent virtual circuit is the packet network equivalent of a leased line.

    physical level
    A standard that defines the electrical, physical, functional, and procedural methods used to control the physical link running between the DTE and the DCE.

    protocol
    A set of semantic and syntactic rules that determines the behavior of functional units in achieving communication. (I)

    PSDN
    packet switching data network.

    PTT
    Post Telephone and Telegraph Administration.

    PVC
    permanent virtual circuit.

    Q

    qualifier-bit (Q-bit)
    A bit in a data packet header indicating the type of information contained in the packet. A 0-bit indicates control information, and a 1-bit indicates data.

    R

    RCM
    Realtime control microcode.

    realtime control microcode
    Firmware supplied with the IBM X.25 Interface Co-Processor/2 adapter

    reset procedure
    On a virtual circuit, reinitialization of data flow control. At reset, all data in transit are eliminated, but the connectivity of the logical channel is maintained.

    restart procedure
    A procedure used by a DTE or DCE to clear all virtual calls and reset all permanent virtual circuits.

    RIC
    Realtime Interface Co-processor. The generic name given to a family of IBM communication adapters.

    S

    SVC
    Switched virtual circuit.

    switched virtual circuit (SVC)
    A virtual circuit that is requested by a virtual call. It is released when the virtual circuit is cleared.

    synchronous data transfer
    A physical transfer of data to or from a device that has a predictable time relationship with the execution of an I/O request.

    V

    virtual call
    See virtual call facility.

    virtual call facility
    In data communication, a user facility in which a call setup procedure and a call clearing procedure determine a period of communication between two data terminal equipments (DTEs) in which user data is transferred in the network in the packet mode of operation. All user data is delivered from the network in the order it is received by the network. It is the packet network equivalent of a dialled line.

    virtual circuit
    In packet switching, the facilities provided by a network that give the appearance to the user of an actual connection. (T)
    A logical connection established between two data terminal equipments (DTEs).

    W

    window
    In data communication, the number of data packets a DTE or DCE can send across a logical channel before waiting for authorization to send another data packet. The window is the main mechanism of pacing, or flow control, of packets.

    X

    X.21
    In data communication, a recommendation of the CCITT that defines the interface between data terminal equipment and public data networks for digital leased and circuit switched synchronous services.

    X.21 bis
    An interim standard that allows existing V-series equipment to be connected to public data networks.

    X.25
    In data communication, a recommendation of the CCITT that defines the interface between data terminal equipment and packet switching networks. Recommendations X.25 (1976), X.25 (Geneva 1980), and X.25 (Malaga-Torremolinos 1984) have been published.

    X.25 network
    A service providing packet-switched data transmission that conforms to Recommendation X.25 adopted by the CCITT.

    X.25 verb
    In IBM X.25 Co-Processor Support Program, a library routine provided for the management, control, or use of an X.25 network. An external verb can be issued by an application; an internal verb is provided for management or for data link control and is not available to applications.

    XVRB
    X.25 verb-request control block.

    X.3
    The CCITT recommendation that specifies the service provided to an asynchronous (start/stop) device by a packet assembler/disassembler (PAD).

    X.25 verb request control block (XVRB)
    A block passed to IBM X.25 Co-Processor Support Program that contains data about a verb being issued.

    X.28
    The CCITT recommendation that specifies the user interface between an asynchronous (start/stop) device and a packet assembler/disassembler (PAD).

    X.29
    The CCITT recommendation that specifies the user interface between a DTE and a remote packet assembler/disassembler (PAD).
     

    Last modified: March 25, 1999