RS/6000 AIXLink/X.25 Cookbook November 1996 SG24-4475-01

RS/6000 AIXLink/X.25 Cookbook November 1996 SG24-4475-01
SG24-4475-01
RS/6000 AIXLink/X.25 Cookbook
November 1996
IBML
International Technical Support Organization
RS/6000 AIXLink/X.25 Cookbook
November 1996
SG24-4475-01
Take Note!
Before using this information and the product it supports, be sure to read the general information in
Appendix I, “Special Notices” on page 297.
Second Edition (November 1996)
This edition applies to Version 1.1.3 of AIXLink/X.25, 5696-926 for use with Version 4 of the AIX/6000 Operating
System.
Comments may be addressed to:
IBM Corporation, International Technical Support Organization
Dept. JN9B Building 045 Internal Zip 2834
11400 Burnet Road
Austin, Texas 78758-3493
When you send information to IBM, you grant IBM a non-exclusive right to use or distribute the information in any
way it believes appropriate without incurring any obligation to you.
 Copyright International Business Machines Corporation 1996. All rights reserved.
Note to U.S. Government Users — Documentation related to restricted rights — Use, duplication or disclosure is
subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp.
Contents
Figures
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Tables
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Preface
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How This Redbook Is Organized
The Team That Wrote This Redbook
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Comments Welcome
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Chapter 1. An Introduction to the X.25 Protocol . .
1.1 Network Communications with X.25 . . . . . . .
1.1.1 Description . . . . . . . . . . . . . . . . . . .
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1.1.2 Standardization
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1.2 Advantages and Disadvantages of X.25
1.2.1 Advantages . . . . . . . . . . . . . . . . . . .
1.2.2 Disadvantages . . . . . . . . . . . . . . . . .
1.3 Components of a PSDN: DSEs, DTEs and DCEs
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1.4 The Three Levels of X.25
1.4.1 Physical Level . . . . . . . . . . . . . . . . .
1.4.2 Link Level . . . . . . . . . . . . . . . . . . . .
1.4.3 Packet Level . . . . . . . . . . . . . . . . . .
1.5 Network User Address (NUA) . . . . . . . . . . .
1.6 Logical Channels and Virtual Circuits . . . . . .
1.6.1 Definition . . . . . . . . . . . . . . . . . . . .
1.6.2 Logical Channel . . . . . . . . . . . . . . . .
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1.6.3 Virtual Circuit
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1.6.4 Multiplexing
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1.6.5 Types of Virtual Circuits
1.7 Facilities . . . . . . . . . . . . . . . . . . . . . . .
1.7.1 Definition . . . . . . . . . . . . . . . . . . . .
1.7.2 Use of Facilities . . . . . . . . . . . . . . . .
1.7.3 Types of Facilities . . . . . . . . . . . . . . .
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1.8 X.25 Network Subscription
1.9 Summary of IBM Support Experiences . . . . .
1.9.1 Planning Considerations . . . . . . . . . . .
1.9.2 Application Selection . . . . . . . . . . . . .
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Chapter 2. RISC System/6000 X.25 Support
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2.1 RISC System/6000 Functions Summary . . . . . . . . . . .
2.1.1 Number of Virtual Circuits Supported . . . . . . . . .
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2.2 RISC System/6000 X.25 Components
2.2.1 IBM X.25 Interface Co-Processor and Co-Processor/2
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2.2.2 IBM ARTIC Portmaster Adapter/A
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2.2.3 IBM ISA Multiport Model II Adapter
2.2.4 IBM ARTIC960 Adapter . . . . . . . . . . . . . . . . . .
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2.2.5 X.25 Device Driver and X.25 Ports
2.2.6 X.25 Commands . . . . . . . . . . . . . . . . . . . . . .
2.2.7 PAD Support . . . . . . . . . . . . . . . . . . . . . . . .
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2.2.8 NPI Programming Interface
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2.2.9 DLPI Programming Interface
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2.2.10 COMIO Emulation
 Copyright IBM Corp. 1996
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2.2.11 SNMP
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2.2.12 SMP machines and X.25
2.2.13 X.32 . . . . . . . . . . . . . . . . . . . . . . . . .
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2.3 X.25 Power Management
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2.3.1 General Power Management and X.25
2.3.2 Impact to Network Provider . . . . . . . . . . .
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2.3.3 Impact to Local Applications
2.3.4 Power Management Limitation Warnings . . .
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2.4 Hardware Requirements
2.5 Differences Between X.25 Support on AIX Versions
2.5.1 Adapter Speeds . . . . . . . . . . . . . . . . . .
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Chapter 3. X.25 LPP Installation and Setup . . . . . . . . . . . . . . . .
3.1 Overview and Fast Path . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.1 Scenario 1: Two RISC System/6000s Connected to a PSDN .
3.1.2 Scenario 2: Two RISC System/6000s Connected by a Modem
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Eliminator
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3.2 Hardware Installation
3.2.1 Installing the Adapter . . . . . . . . . . . . . . . . . . . . . . . .
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3.2.2 Physical Connections to the Network
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3.2.3 X.25 Connection Test Scenarios
3.2.4 Mo d e m Considerations . . . . . . . . . . . . . . . . . . . . . . .
3.3 Software Customization . . . . . . . . . . . . . . . . . . . . . . . . .
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3.3.1 Installing the X.25 LPP Software
3.3.2 Configuring the X.25 Device Driver . . . . . . . . . . . . . . . .
3.3.3 Configuring an X.25 LPP Port . . . . . . . . . . . . . . . . . . .
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3.3.4 Updating the Number of Virtual Channels
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3.3.5 Modifying Other Parameters
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3.3.6 Customization for the Back-to-Back Scenario
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3.4 Returning to the Default Configuration Parameters
3.5 Configuring V.25bis Dialing . . . . . . . . . . . . . . . . . . . . . . .
3.6 Configuring ISA X.25 Adapters . . . . . . . . . . . . . . . . . . . . .
3.6.1 Configuring ISA X.25 Adapters at the Hardware Level . . . .
3.6.2 Configuring ISA X.25 Adapters at the Software Level . . . . .
3.7 X.25 Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3.7.1 Facilities Requested by the DTE
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3.7.2 More on Configuring Facilities
Chapter 4. Tools . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 The xtalk Tool . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . .
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4.1.2 Overview and Fast Path
4.1.3 The xtalk Command . . . . . . . . . . . . . . . . . . . .
4.1.4 Testing Communication with xtalk . . . . . . . . . . .
4.1.5 Requesting the Use of a Facility with xtalk . . . . . .
4.2 The x25mon Tool . . . . . . . . . . . . . . . . . . . . . . . .
4.2.1 Description . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2 Using the x25mon Tool . . . . . . . . . . . . . . . . . .
4.3 The xroute Tool . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1 The Routing Table . . . . . . . . . . . . . . . . . . . . .
4.3.2 Updating the X.25 Routing Table with the xroute Tool
4.4 Other X.25 Commands . . . . . . . . . . . . . . . . . . . . .
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4.5 Configuration Tools
4.5.1 The backupx25 Script . . . . . . . . . . . . . . . . . . .
4.5.2 The restorex25 Script . . . . . . . . . . . . . . . . . . .
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RS/0000 X.25 Cookbook
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4.5.3 The removex25 Script
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Chapter 5. Packet Assembler Disassembler (PAD)
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5.1 Using a PAD . . . . . . . . . . . . . . . . . . . . . . . .
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5.2 Function of the PAD
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5.2.1 X.3, X.28 and X.29 Standards
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5.2.2 Outgoing PADs
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5.2.3 Incoming PADs
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5.3 CCITT PAD Interfaces
5.3.1 PAD Parameters . . . . . . . . . . . . . . . . . . .
5.3.2 PAD Commands . . . . . . . . . . . . . . . . . . .
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5.3.3 PAD Profiles
5.4 Configuring the PAD . . . . . . . . . . . . . . . . . . .
5.4.1 PAD for AIXLink/X.25 1.1.2 Running on AIX V.4
5.4.2 PAD for AIXLink/X.25 1.1.3 (and later) on AIX V.4
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5.4.3 Default Initial Application
5.4.4 Selectable Profile . . . . . . . . . . . . . . . . . .
5.4.5 Configurable Profile . . . . . . . . . . . . . . . . .
5.4.6 Security Features . . . . . . . . . . . . . . . . . .
5.5 PAD printing . . . . . . . . . . . . . . . . . . . . . . . .
5.5.1 Setting up the PAD Printer Queue . . . . . . . .
5.5.2 PAD Printing Process . . . . . . . . . . . . . . . .
5.5.3 Configuration for Remotely Initiated Printing . .
5.5.4 Configuration of Locally Initiated Printing . . . .
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5.6 PAD Usage
5.7 Incoming PAD Setup . . . . . . . . . . . . . . . . . . .
5.7.1 Listing the Configured Ports . . . . . . . . . . . .
5.7.2 Stopping the X.29 Daemon . . . . . . . . . . . . .
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5.7.3 Starting the X.29 Daemon
5.8 Setup of an Integrated PAD . . . . . . . . . . . . . . .
5.8.1 Starting the PAD Program . . . . . . . . . . . . .
5.8.2 Exiting . . . . . . . . . . . . . . . . . . . . . . . . .
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5.9 X.25 PAD and C-Kermit
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5.9.1 Requirements
5.9.2 Documentation . . . . . . . . . . . . . . . . . . . .
5.9.3 AIX X.25 PAD as a C-Kermit Client . . . . . . . .
5.9.4 AIX X.25 PAD as a C-Kermit Server . . . . . . .
5.9.5 Session Statistics . . . . . . . . . . . . . . . . . .
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Chapter 6. APIs: COMIO, NPI and DLPI . . . . . . . . . . . . . .
6.1 Implementation of X.25 in the STREAMS Environment . . .
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6.2 STREAMS
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6.2.1 STREAMS Definition
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6.2.2 STREAMS Components
6.2.3 Benefits of STREAMS . . . . . . . . . . . . . . . . . . . .
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6.2.4 How to use STREAMS
6.3 NPI API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3.1 NPI Implementation on the RS/6000 . . . . . . . . . . .
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6.3.2 NPI Primitives Available on the RS/6000
6.3.3 Use of the Primitives . . . . . . . . . . . . . . . . . . . .
6.3.4 Description of the NPI Samples Available with the LPP
6.4 DLPI API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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6.4.1 DLPI Implementation on the RS/6000
6.4.2 Establishment of a Stream to DLPI . . . . . . . . . . . .
6.4.3 DLPI Primitives Available on the RS/6000 . . . . . . . .
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Contents
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6.4.4 Description of the DLPI Samples Available with the X.25 LPP
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6.5 COMIO API
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6.5.1 COMIO Definition
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6.5.2 Using COMIO
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6.5.3 X.25 Example Programs
Chapter 7. TCP/IP Setup . . . . . . . . . . . . . . . .
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7.1 Introduction
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7.2 TCP/IP X.25 Connection Setup and Test
7.2.1 Creating Entries in /etc/hosts . . . . . . . .
7.2.2 Initializing and Starting the IP/X.25 Interface
7.2.3 Adding Routes for the Remote Systems . .
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7.2.4 Mapping IP Addresses to X.25 NUAs
7.2.5 Testing the Connection . . . . . . . . . . . .
7.2.6 Suppressing the X.25 LPP IP Interface . . .
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7.3 Requesting the Use of a Facility with TCP/IP
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7.4 Changing TCP/IP CUD Values
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7.5 Configuring SNMP
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Chapter 9. X.25 Problem Determination . . . . . . . . . . . . . .
9.1 X.25 Problem Diagnosis . . . . . . . . . . . . . . . . . . . . .
9.2 Diagnosing Problems with Connecting to the X.25 Network
9.3 Diagnosing Problems with Making an Outgoing X.25 Call .
9.4 Diagnosing Problems with Receiving an Incoming X.25 Call
9.5 Diagnosing X.25 Packet Problems . . . . . . . . . . . . . . .
9.6 Diagnosing X.25 Command Problems . . . . . . . . . . . . .
9.7 Diagnosing xtalk Problems . . . . . . . . . . . . . . . . . . .
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9.7.1 Device Driver Problems
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9.7.2 X.25 Protocol Problems
9.8 Diagnosing TCP/IP Problems . . . . . . . . . . . . . . . . . .
9.8.1 Preliminary Checks . . . . . . . . . . . . . . . . . . . . .
RS/0000 X.25 Cookbook
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Chapter 8. Accessing an SNA Network with X.25 . . . . . . . .
8.1 QLLC with Reference to RISC System/6000 X.25 Support .
8.2 Introduction to SNA Server/6000 . . . . . . . . . . . . . . . .
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8.2.1 SNA Application Programming Interfaces (APIs)
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8.2.2 SNA Configuration Profiles
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8.2.3 SNA Configuration Database and Commands
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8.2.4 SNA Server Components
8.3 AIX SNA Server/6000 Setup . . . . . . . . . . . . . . . . . . .
8.3.1 Installation of the AIX SNA Server/6000 LPP . . . . . .
8.3.2 Installation of the Data Link Control . . . . . . . . . . .
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8.3.3 Getting Host Definitions
8.3.4 SNA Profiles for an X.25 LU 2 . . . . . . . . . . . . . . .
8.3.5 Performing Initial Node Setup . . . . . . . . . . . . . . .
8.3.6 Setting Up the SNA profiles for LU 2 . . . . . . . . . . .
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8.3.7 Verifying SNA Profiles
8.3.8 Starting SNA Server/6000 Server . . . . . . . . . . . . .
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8.3.9 Starting SNA Server/6000 Link Station
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8.3.10 Listing Current Status of SNA Server/6000
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8.4 3270 Host Connection Program/6000
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8.4.1 Overview
8.4.2 Setup and Use of 3270 Host Connection Program/6000
8.4.3 SNA Problems . . . . . . . . . . . . . . . . . . . . . . . .
8.4.4 HCON Problems . . . . . . . . . . . . . . . . . . . . . . .
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9.8.2 Testing with ping
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9.8.3 Function Keys not Working Properly . . . . . . . . .
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9.9 Diagnosing SNA Server Problems on AIX V4
9.10 Basic Information Required . . . . . . . . . . . . . . . .
9.10.1 Problem Definition . . . . . . . . . . . . . . . . . . .
9.10.2 Profiles . . . . . . . . . . . . . . . . . . . . . . . . . .
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9.10.3 SNA Server/6000 Traces
9.10.4 LU 0 Information . . . . . . . . . . . . . . . . . . . .
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9.10.5 System Error Log
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9.10.6 HCON Trace
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9.10.7 SNA_ABEND
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9.10.8 Trace Hooks for X.25
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9.11 System Errors
9.11.1 Flashing 888 . . . . . . . . . . . . . . . . . . . . . . .
9.11.2 System Dump . . . . . . . . . . . . . . . . . . . . . .
9.12 Collecting Information for Resolution of X.25 Problems
9.12.1 List of Elements to Gather . . . . . . . . . . . . . .
9.13 How to Resolve an X.25 ′Device Busy′ Condition . . .
9.13.1 Problem Identification . . . . . . . . . . . . . . . . .
9.13.2 Problem Solution . . . . . . . . . . . . . . . . . . . .
9.13.3 If All Else Fails . . . . . . . . . . . . . . . . . . . . .
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9.14 Improving FTP Performance over X.25
9.15 ARTIC960 Software Problems . . . . . . . . . . . . . . .
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9.16 Examples of X.25 PAD Problem Determination
9.16.1 Providing Initial Statement of Fault . . . . . . . . .
9.16.2 X.25 Hardware Connection . . . . . . . . . . . . . .
9.16.3 Device Driver . . . . . . . . . . . . . . . . . . . . . .
9.16.4 Connection State . . . . . . . . . . . . . . . . . . . .
9.16.5 Total Line Termination or Failure to Start . . . . .
9.16.6 Connected to X.25 Network No Traffic Flow . . . .
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9.16.7 Transient Dropouts
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9.16.8 Application
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9.16.9 Printing
Chapter 10. Performance and Tuning
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10.1 Line Speed . . . . . . . . . . . . . . . . . . . . . . .
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10.2 Transit Delay Versus Data Throughput
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10.3 Factors That May Limit Throughput
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10.3.1 X.25 Adapter
10.3.2 DTE-to-DCE Line Speed and Throughput Class
10.3.3 Influence of the Application Design . . . . . .
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10.4 Network Configuration Parameters
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10.5 Applications
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10.5.1 X.25 LPP PAD Versus TCP/IP
10.5.2 TCP/IP . . . . . . . . . . . . . . . . . . . . . . .
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10.5.3 SNA
10.6 Memory Buffers . . . . . . . . . . . . . . . . . . . .
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Appendix A. Summary of the SMIT Main Menus Used for Configuration
A.1 X.25 Adapter Configuration . . . . . . . . . . . . . . . . . . . . . . . .
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A.2 TCP/IP Configuration
A.3 SNA Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Appendix B. Differences Between X.25 LPP and AIX V3 Base X.25 Support
B.1 Hardware Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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B.2 Functionality Differences
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B.2.1 Differences between (CCITT) 1988 and 1984 X.25
B.3 Configuration and Setup Differences . . . . . . . . .
B.4 Command Differences . . . . . . . . . . . . . . . . . .
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B.5 ODM/SMITAttributes Differences
B.6 Default Values of Important Parameters . . . . . . .
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Appendix C. X.25 Cables and Connectors
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C.1 IBM X.25 Co-Processor and IBM X.25 Co-Processor/2 . . . . . . . . .
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C.1.1 X.25 Co-Processor 37-Pin Connector Pin Assignment
C.1.2 X.25 Co-Processor Modem Attachment Pin Assignment . . . . .
C.1.3 X.25 Co-Processor Interconnection Cables . . . . . . . . . . . . .
C.1.4 X.25 Co-Processor Adapter and Cable Diagnostics . . . . . . . .
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C.2 IBM Portmaster Adapter/2 and Multiport Model 2
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C.2.1 IBM ARTIC Portmaster Adapter/A Pin-Out Information
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C.2.2 Modem Attachment Pin Assignment
C.2.3 X.25 Portmaster and Multiport Interconnection Cables . . . . . .
C.2.4 X.25 Portmaster, Multiport and ARTIC960 Diagnostic Wrap Plugs
Appendix D. CCITT Causes and Diagnostics .
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D.1 CCITT Clear and Reset Causes
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D.2 CCITT Diagnostic Codes
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D.3 Product-Specific Diagnostic Codes
D.4 ISO 8208 Diagnostic Codes . . . . . . . . .
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D.5 SNA Diagnostic Codes
D.5.1 List of Diagnostic Codes Used by xtalk
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D.5.2 Logical Channel States
RS/0000 X.25 Cookbook
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Appendix E. Facilities
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E.1 Supported Facilities for X.25 Communications
E.1.1 Defining Facilities . . . . . . . . . . . . . . . . . . .
E.1.2 Facilities Format . . . . . . . . . . . . . . . . . . . .
E.1.3 Index of the Facilities . . . . . . . . . . . . . . . . .
E.2 X.25 Facilities . . . . . . . . . . . . . . . . . . . . . . . .
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E.2.1 Packet Size Selection
E.2.2 Window Size Selection . . . . . . . . . . . . . . . .
E.2.3 Throughput Class . . . . . . . . . . . . . . . . . . .
E.2.4 Closed User Group Selection . . . . . . . . . . . .
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E.2.5 CUG with Outgoing Access
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E.2.6 Bilateral Closed User Group Selection
E.2.7 Reverse Charging and Fast Select . . . . . . . . .
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E.2.8 Network User Identification
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E.2.9 Charging Information Request
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E.2.10 Charging (Monetary Unit)
E.2.11 Charging (Segment Count) . . . . . . . . . . . . .
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E.2.12 Charging (Call Duration)
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E.2.13 RPOA Selection
E.2.14 Called Line Address Modified Notification . . . .
E.2.15 Call Redirection Notification . . . . . . . . . . . .
E.2.16 Transit Delay Selection and Indication . . . . . .
E.3 CCITT Specified Facilities to Support the OSI Network
E.3.1 Calling Address Extension . . . . . . . . . . . . . .
E.3.2 Called Address Extension . . . . . . . . . . . . . .
E.3.3 Minimum Throughput Class . . . . . . . . . . . . .
E.3.4 End-to-End Transmit Delay Facility . . . . . . . . .
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E.3.5 Expedited Data Negotiation
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Appendix F. PAD Parameters and Commands
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F.1 PAD Parameters
F.2 Detailed Description of PAD Parameters
F.3 Commands Entered from the PAD Prompt
F.4 Messages from the PAD to the Terminal
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Appendix G. CIO and X.25 Device Driver Error Codes
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Appendix J. Related Publications
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J.1 International Technical Support Organization Publications
J.2 Redbooks on CD-ROMs . . . . . . . . . . . . . . . . . . . .
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J.3 Other Publications
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J.3.1 Articles
J.4 Non-IBM References . . . . . . . . . . . . . . . . . . . . . .
How To Get ITSO Redbooks . . . . . . . . . .
How IBM Employees Can Get ITSO Redbooks
How Customers Can Get ITSO Redbooks . .
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IBM Redbook Order Form
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Index
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Appendix H. Country Networks Default Parameters
Appendix I. Special Notices
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Contents
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 Copyright IBM Corp. 1996
Advantages and Disadvantages of X.25 Compared to Dial-up
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Transmission
An X.25 Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OSI, X.25 Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HDLC Frame Structures . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Establishing a Switched Virtual Circuit
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Clearing a Switched Virtual Circuit
DTE Initiated Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DCE Initiated Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Packet Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Network User Address (NUA) Structure . . . . . . . . . . . . . . . . . .
Logical Channels and Virtual Circuits . . . . . . . . . . . . . . . . . . .
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Facilities and Call Packets
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Call Packet Formats
IBM X.25 Interface Co-Processors . . . . . . . . . . . . . . . . . . . . .
IBM ARTIC Portmaster Adapter/A Configurations . . . . . . . . . . . .
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IBM ARTIC Multiport Adapter Model II Configurations
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IBM ARTIC960 Adapter Configurations
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Adapter, Device Driver, Port, Interface
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RISC System/6000s Connected to the TYMNET PSDN
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RISC System/6000s Connected Back-to-Back
Two RISC System/6000s Connected to an X.25 Network . . . . . . . .
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One RISC System/6000 Connected to an X.25 Network
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Two RISC System/6000s Connected to an X.25 Network Simulator
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Two RISC System/6000s Connected Back-to-Back
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One RISC System/6000 with Two X.25 Co-Processors
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Two RISC System/6000s Connected Back-to-Back
xtalk Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Various Types of PADs . . . . . . . . . . . . . . . . . . . . . . . . .
X.3, X.28 and X.29 Standards . . . . . . . . . . . . . . . . . . . . . . . .
Public PAD vs. Integrated Private PAD . . . . . . . . . . . . . . . . . .
Private PADs Used to Carry Asynchronous Connections over a PSDN
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X.25 In the STREAMS Environment
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Components of a Stream
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The Portability of the STREAMS Architecture
Easy Migration with the STREAMS Architecture . . . . . . . . . . . . .
Reusability of STREAMS Modules . . . . . . . . . . . . . . . . . . . . .
Multiplexing Facility of the STREAMS . . . . . . . . . . . . . . . . . . .
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NPI Components
The Building of a NPI Stream . . . . . . . . . . . . . . . . . . . . . . . .
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Structure of the npiserver.c Program
Structure of the npiclient.c Program . . . . . . . . . . . . . . . . . . . .
DLPI Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Structure of the dlpiserver.c Program . . . . . . . . . . . . . . . . . . .
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Structure of the dlpiclient.c Program
COMIO Emulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test Configuration for TCP/IP . . . . . . . . . . . . . . . . . . . . . . . .
Scenario for an SNA Connection Using X.25 . . . . . . . . . . . . . . .
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Generic AIX SNA Server/6000 Profiles for HCON
AIX SNA Server/6000 Configuration Process . . . . . . . . . . . . . . .
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X.25 AIX SNA Server/6000 Profiles for HCON
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xii
RS/0000 X.25 Cookbook
Establishing a Switched Virtual Circuit
. . . . . . .
Call Packet Structure . . . . . . . . . . . . . . . . . .
Call Cleared by the DCE . . . . . . . . . . . . . . . .
Call Cleared by the Remote DTE . . . . . . . . . . .
. . . . . . . . . . .
Call Cleared by the Calling DTE
AIX SNA Services/6000 Main Profiles . . . . . . . .
. . . . . . . . . . . . . . . .
Co-Processor Adapters
. . . . . . . . . . . . . . . . . .
X.21 Interface Cable
. . . . . . . . . . . . .
X.21bis/V.24 Interface Cable
. . . . . . . . . . . . .
X.21bis/V.35 Interface Cable
. . . . . . . . . . . . . . . . . . . . .
D-37 Wrap Plug
. . . . . . . . . . . . . . . . . . . . .
D-15 Wrap Plug
. . . . . . . . . . . . . . . . . . . . .
D-25 Wrap Plug
M/34 Wrap Plug . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . .
Portmaster and Multiport
. . . . . . . . . . . . . . . . . .
X.21 Interface Cable
. . . . . . . . . . . . .
X.21bis/V.24 Interface Cable
. . . . . . . . . . . . .
X.21bis/V.35 Interface Cable
. . . . . . . . . . . . . . . . . . . . .
D-15 Wrap Plug
. . . . . . . . . . . . . . . . . . . . .
D-25 Wrap Plug
M/34 Wrap Plug . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .
D-25 Wrap Plug
. . . . . . . . . . . . . . . . . . . . .
D-25 Wrap Plug
. . . . . . . . . . . . . . . . . . . . .
D-37 Wrap Plug
. . . . . . . . . . . . . . . . . .
D-78 X.21 Wrap Plug
. . . . . . . . . . . . . . . . . . . .
D-100 Wrap Plug
. . . . . . . . . . . . . . . . .
D-100 V.24 Wrap Plug
. . . . . . . . . . . . . .
D-100 V.36/V.35 Wrap Plug
. . . . . . . . . . . . . . . . . . . .
Facilities Format
Facility Code Format . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .
Packet Size Selection
Window Size Selection . . . . . . . . . . . . . . . . .
Throughput Class . . . . . . . . . . . . . . . . . . . .
. . .
Closed User Group Selection (Basic Format)
Closed User Group Selection (Extended Format) .
CUG with Outgoing Access (Basic Format) . . . . .
. .
CUG with Outgoing Access (Extended Format)
. . . . . . .
Bilateral Closed User Group Selection
Reverse Charging and Fast Select . . . . . . . . . .
Network User Identification . . . . . . . . . . . . . .
. . . . . . . . . . . .
Charging Information Request
Charging (Monetary Unit) . . . . . . . . . . . . . . .
. . . . . . . . . . . . . .
Charging (Segment Count)
Charging (Call Duration) . . . . . . . . . . . . . . . .
. . . . . . . . . . .
RPOA Selection (Basic Format)
. . . . . . . . .
RPOA Selection (Extended Format)
. . . . .
Called Line Address Modified Notification
Called Line Address Modified Notification (CLAMN)
. . . . . . . . . . . . .
Call Redirection Notification
. . . . . . .
Transit Delay Selection and Indication
Calling Address Extension . . . . . . . . . . . . . . .
Called Address Extension . . . . . . . . . . . . . . .
Minimum Throughput Class . . . . . . . . . . . . . .
End-to-End Transmit Delay Facility . . . . . . . . . .
Expedited Data Negotiation . . . . . . . . . . . . . .
. . . . . . . . . . . .
. . . . . . . . . . . .
. . . . . . . . . . . .
. . . . . . . . . . . .
. . . . . . . . . . . .
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187
188
190
190
190
234
247
253
254
255
255
256
256
256
257
261
261
262
262
263
263
263
264
264
265
266
267
268
275
276
277
277
278
278
278
279
279
279
279
280
280
281
281
281
282
282
282
283
283
284
284
285
285
286
286
Tables
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
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25.
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27.
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35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
 Copyright IBM Corp. 1996
X.25 Optional Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Throughput of the X.25 Adapters . . . . . . . . . . . . . . . . . . . . . . .
Differences Between AIX Version 3.2.5, AIXLink Ver. 1.1 and AIXLink
Ver. 1.1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Value of Important Parameters . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .
NUAs Used for Back-to-Back Scenario
. . . . . . . . . . . . . . . . . . . . . . .
Interrupt Level Switch Positions
X.25 Adapter: Switch Block 1 . . . . . . . . . . . . . . . . . . . . . . . . .
X.28 Facility Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clearing Codes
. . . . . . . . . . . . .
Parameter Settings for Predefined PAD Profiles
Parameter Settings for Default PAD Profiles . . . . . . . . . . . . . . . .
SNA Host Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
SNA Problem Checklist
. . . . . . . . .
Information to Gather for Specific Problem Categories
Trace Reports and Associated Hook IDs . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
X.25 Problem Checklist
. . . . . . . . . . . . . . .
SMIT Menus for the Base X.25 Configuration
. . . . . . . . . . . . . . . . .
SMIT Menus for the TCP/IP Configuration
SMIT Menus for the SNA Configuration . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .
X.25 Supported Adapters
Functional Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMIT Fastpaths Differences . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
Differences Between xmonitor and x25mon
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SMIT Attribute Names
. . . . . . . . . . . . . . . . . .
Default Values of Important Parameters
X.25 Co-Processor 37-Pin Connector Pin Assignment . . . . . . . . . .
Pin Assignment of V.11 Type of Interface Circuits to 15-Pin Connectors
V.24/X.21bis Pin Assignment to 25-Pin Connector (Speeds up to 20
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kbps)
V.35/X.21bis Pin Assignment to 34-Pin Connector (Speeds above 20
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
kbps)
. . . . . . . . . . . . . . . . .
V.36 Pin Assignment to 37-Pin Connector
Portmaster and Multiport: V.35 . . . . . . . . . . . . . . . . . . . . . . . .
Portmaster and Multiport: V.24 . . . . . . . . . . . . . . . . . . . . . . . .
Portmaster and Multiport: X.21 . . . . . . . . . . . . . . . . . . . . . . . .
List of CCITT Clear Causes . . . . . . . . . . . . . . . . . . . . . . . . . .
List of CCITT Reset Causes . . . . . . . . . . . . . . . . . . . . . . . . . .
List of CCITT Diagnostic Codes . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .
List of Product-Specific Diagnostic Codes
List of ISO 8208 Diagnostic Codes . . . . . . . . . . . . . . . . . . . . . .
List of SNA Diagnostic Codes . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .
List of xtalk Diagnostic Codes
Index of Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . .
User-Customizable PAD Parameters Defined in X.3
. . . . . . . .
Detailed Descriptions of PAD Parameters Defined in X.3
. . . . . . . . . .
Commands that can be Issued from the PAD Prompt
Service Signals Sent from the X.3 PAD to the X.28 Terminal . . . . . .
Default Parameters for the Various Networks . . . . . . . . . . . . . . .
.
.
17
40
40
60
. 62
. 65
. 66
. 99
100
101
102
160
195
197
201
210
227
231
235
239
240
243
244
244
246
248
249
.
.
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253
257
259
260
269
269
269
271
271
271
274
276
287
289
290
292
295
xiii
xiv
RS/0000 X.25 Cookbook
Preface
This document is intended for users of AIXLink/X.25 V1.1.3 Licensed Program
Product.
The AIX/V3 X.25 Communication Cookbook , GG24-3692-01, is still available and is
intended for users of the AIX X.25 product shippped with the AIX 3.2 base
operating system.
This document describes the set up and testing of X.25 communications on the
RISC System/6000. It explains, step-by-step, how to install hardware and
software, customize the X.25 support, test the connection to the network, and
establish a virtual call between two systems. The use of the APIs available and
the setup of the included PAD of TCP/IP and SNA 3270 emulator in an X.25
environment are also described. Descriptions of the X.25 concepts, components,
and protocols are also included.
This document is intended for customers and system engineers who plan to
install X.25 Licensed Program Product (LPP) communications on the RISC
System/6000. A knowledge of AIX/6000 is assumed.
How This Redbook Is Organized
This redbook contains 313 pages. It is organized as follows:
•
Chapter 1, “An Introduction to the X.25 Protocol”
This chapter is an overview of the X.25 protocol and terminology.
•
Chapter 2, “RISC System/6000 X.25 Support”
This chapter briefly describes all the features included in the X.25 LPP on the
RISC System/6000.
•
Chapter 3, “X.25 LPP Installation and Setup”
This chapter describes the hardware and software installation of the X.25
LPP on the RISC System/6000, the modem setup and the minimal
customization of the X.25 LPP for switched virtual circuits.
•
Chapter 4, “Tools”
This chapter describes the use of the three main tools available in the X.25
LPP and describes briefly each command specific to the X.25 LPP.
•
Chapter 5, “Packet Assembler Disassembler (PAD)”
This chapter reviews the PAD protocols (CCITT X.3, X.28, X.29), also called
Triple X, and describes the customization and use of the PAD included in the
X.25 LPP.
•
Chapter 6, “APIs: COMIO, NPI and DLPI”
This chapter presents the APIs available in the X.25 LPP. Before the
presentation of the APIs, a review of the STREAMS mechanism is included,
since these APIs are based on the Portable STREAMS Environment
•
 Copyright IBM Corp. 1996
Chapter 7, “TCP/IP Setup”
xv
This chapter shows how to set up and test TCP/IP communications over an
X.25 network. It also explains the setup of SNMP to use the X.25 MIB
available with the X.25 LPP.
•
Chapter 8, “Accessing an SNA Network with X.25”
This chapter describes how to set up and test SNA communications over an
X.25 network. The end of the chapter describes the use of 3270 Host
Connection Program/6000, which allows the RISC System/6000 to
communicate with System/390 computer systems.
•
Chapter 9, “X.25 Problem Determination”
This chapter provides information that is intended to be helpful in problem
determination.
•
Chapter 10, “Performance and Tuning”
This chapter discusses performance considerations on the RISC System/6000
X.25 adapters and on the main applications (PAD, TCP/IP, SNA) over an X.25
link.
The Team That Wrote This Redbook
This redbook was produced by a team of specialists from around the world
working at the International Technical Support Organization, Austin Center.
Al Mitchell is a Senior SE Support Representative at the International Technical
Support Organization, Austin Center. He writes extensively and teaches IBM
classes worldwide on all areas of AIX communications. Before joining the ITSO
two years ago, he worked in USM&S as an Senior AIX Marketing Support
Specialist.
Sue Foulds is an AIX Systems Support Specialist in the UK. She has five years
of experience in the AIX Networking field. Her areas of expertise include X.25
and SNA She has written extensively on these subjects.
Praben Primasaputra is an AIX Country Support Systems Engineer in Jakarta,
Indonesia. He has been with IBM for six years, and has five years of experience
in AIX, with the last two years specializing in Networking. He holds a degree in
Telecommunication Engineering from Sepuluh November Institute of Technology,
Surabaya, Indonesia. His areas of expertise include, HACMP/6000, SNA Server,
X.25, AIX Performance Tuning, and TME 10 (Tivoli). He has written extensively
on AIX System Management for IBM Indonesia operation.
Eduard Spiess is a AIX Support Professinal in Germany He has 10 years of
experience in AIX communication field and has worked at IBM for 27 years. His
areas of expertise include SNA, X25, OSI/6000 and AS/400 communications. He
has written extensively on AIXLink/X.25.
Paul Gunther is a Software Service Specialist in Australia. He has 11 years of
experience in the UNIX/AIX field and has worked at IBM for eight years. He
holds a degree in Computer Science from the Queensland University of
Technology. His areas of expertise include kernel, graphics, and
internetworking. He has written extensively on problem-determination
techniques and Internet exploitation via the World Wide Web.
Thanks to the following people for their invaluable contributions to this project:
xvi
RS/0000 X.25 Cookbook
Mark Grosch
AIX WAN Software Development
Marissa Borrego
AIX WAN Software Development
Jackie Wilson
AIX WAN Software Development
Will Faveash
AIX WAN Software Development
Cindy Young
AIX System Center
Comments Welcome
We want our redbooks to be as helpful as possible. Should you have any
comments about this or other redbooks, please send us a note at the following
address:
[email protected]
Your comments are important to us!
Preface
xvii
xviii
RS/0000 X.25 Cookbook
Chapter 1. An Introduction to the X.25 Protocol
This chapter is an introduction to the X.25 network protocol. It is intended to
provide an understanding of X.25 for users of the AIX X.25 products. Along with
descriptions of the components and layers of X.25, sections are included to
explain the advantages and limitations of the protocol.
The following subjects are discussed in this chapter:
•
Network communications with X.25
•
Advantages and disadvantages of X.25
•
DSEs, DTEs and DCEs
•
The three levels of X.25
•
Network user address (NUA)
•
Logical channels and virtual circuits
•
X.25 packet types
•
X.25 network subscription
•
A summary of IBM support experiences
1.1 Network Communications with X.25
X.25 networks provide wide area communications capabilities in heterogeneous
environments.
1.1.1 Description
X.25 is a set of recommendations from the International Telegraph and
Telephone Consultative Committee (CCITT) that defines a standard network
access protocol for attaching diverse types of computer equipment to a
Packet-Switched Data Network (PSDN). The CCITT consists of representatives
from the Post Telegraph and Telephone authorities from nations around the
world, nearly all of which offer X.25 networking services.
Although some corporations have created private networks, most companies
subscribe to a public PSDN. A PSDN is an interconnecting set of intelligent
switching nodes that enables subscribers to exchange data using a standard
protocol and packet-switching technology. Such a network carries messages,
divided into parts called packets, over circuits that are shared by many network
users. A single physical line into an office can handle many concurrent
connections, each called a virtual circuit. A packet consists of a sequence of
data and control elements in a special format that is always transmitted as a
whole. The network packet size is commonly 128 bytes (octets in X.25
terminology); however, this value can vary from 16 to 4096 bytes.
You can use X.25 communications to provide a network service for higher level
protocols, such as SNA or TCP/IP. You can also use an X.25 network directly,
either by using the xtalk command or by developing applications using one of
the provided X.25 Application Program Interfaces (APIs).
Because several users simultaneously share the same circuits, a protocol is
necessary to ensure that the network correctly routes data to its destination.
 Copyright IBM Corp. 1996
1
1.1.2 Standardization
In 1976, a protocol for attaching user equipment to a PSDN was defined by CCITT
in CCITT Recommendation X.25 (commonly called the “Orange Book”). The
CCITT had full sessions every four years, with proceedings published after each.
Note: CCITT is now ITU-T, International Telegraph and Telephone Union Telecommunications Sector, and it will publish recommendations as they
are adopted, not at 4-year intervals.
Between 1976 and 1980, there were radical changes to the X.25
recommendations. The 1980 session produced the Yellow Book. This gave firm
specifications for many aspects that were previously open to different
interpretation. Subsequently, the 1984 Red Book and 1988 Blue Book contained
comparatively minor enhancements.
The main changes from 1976 to the present in the basic standard and associated
facilities are:
1976
•
First X.25 Recommendation issued
•
Call barring: Incoming and Outgoing
•
Closed User Groups
•
Default packet and window size
•
LAP (Link Access Procedure) only at Data Link Level
•
Reverse charging
•
X.75 first defined
•
Closed User Group facilities enhanced
•
D-bit
•
Datagrams
•
Fast Select
•
Interrupt
•
LAPB at Data Link Level introduced
•
PVCs made essential
•
Reset
•
Throughput Class negotiation
•
Call Redirection
•
Datagrams dropped
•
Expedited data negotiation
•
Facility field length extended to 109 octets
•
Hunt group
•
Multilink procedure
(1978)
1980
1984
2
RS/0000 X.25 Cookbook
•
NUI
•
Online facilities registration
•
OSI Address Extension
•
OSI Quality of Service Facilities
•
X.3 Parameters: four added
•
X.32 Recommendation
•
Call Deflection facility added
•
Long address format for Call Request and Call Clearing packets
1988
The International Organization for Standardization (ISO) also published the X.25
recommendations as ISO 8208 and ISO 7776.
1.2 Advantages and Disadvantages of X.25
Figure 1 shows the advantages and disadvantages of X.25 networking.
┌───────────────────────────────────────────────────────────────────────┐
│
Advantages
Disadvantages
│
├───────────────────────────────────────────────────────────────────────┤
│ Basis of OSI
Unpredictable performance
│
│
│
│ Worldwide network
│
│
│
│ Vendor independence
│
│
│
│ Access to public databases
│
│
│
│ Multiple logical connections
│
│ over a single physical link
│
│
│
│ Network options for security
│
│
│
│ Cost effectiveness
Expensive if traffic is very
│
│
high or very low
│
│
│
│ High data integrity
Overhead with higher-level
│
│
protocols
│
│
│
│ Network is responsibility
User has no control over
│
│ of network vendor
network
│
└───────────────────────────────────────────────────────────────────────┘
Figure 1. Advantages and Disadvantages of X.25 Compared to Dial-up Transmission
1.2.1 Advantages
X.25 can be a cost-effective means of networking systems in a wide geographical
area, compared to traditional dial-up (circuit switched) connections or
remote-bridged Local Area Networks (LANs) connected by leased lines up to
1.33 Mbps (nearly T1). It provides worldwide interconnection for international
corporations. Typically, PSDN suppliers charge a one-time connection fee, a
Chapter 1. An Introduction to the X.25 Protocol
3
monthly subscription charge, and a usage fee based on the number of packets
transmitted across the network during that month.
Organizations use X.25 for many reasons:
•
International Standards: The X.25 recommendations are open standards for
Wide Area Networking (WAN) that form the basis of the Open Systems
Interconnection (OSI) protocols, standards set by the International
Organization for Standardization (ISO).
•
Worldwide Network: Users can communicate with other systems around the
world.
•
Vendor Independence: Every major computer manufacturer supports X.25.
•
High Level of Data Integrity: X.25 provides built-in error detection and data
correction features.
•
Security: X.25 offers built-in security features. For example, Closed User
Groups allow a limited set of addresses that can communicate with each
other to be defined, while refusing access to outside parties. Also, system
administrators can block outgoing calls to stop people from using the
network and running up network costs.
•
Network Responsibility: For smaller organizations, this is perhaps the most
important feature. The network supplier, whether a Post Telegraph and
Telephone (PTT) authority or an independent company, takes full
responsibility for running and managing the network.
•
Access to Information: X.25 is a popular access method for public
databases.
•
Multiple Logical Connections over a Single Physical Link: With one physical
connection, users can multiplex several connections simultaneously.
1.2.2 Disadvantages
Although most of these features are benefits, some users may find them to be
drawbacks. While vendor responsibility for network operations is an advantage
for small to medium sized companies, very large organizations might consider
vendor reliance a serious disadvantage. If something goes wrong, users have
no control unless they are accessing their own private network.
Also, organizations using higher-level protocols, such as Systems Network
Architecture (SNA) or Transmission Control Protocol/Internet Protocol (TCP/IP),
will find that running these higher level protocols over X.25 networks results in
higher overhead costs. X.25 is a fairly high-level protocol with built-in facilities
like flow-control mechanisms. Since network costs reflect per-packet usage,
other protocols that also provide error detection/correction (TCP/IP and SNA)
produce added overhead with extra packets.
Perhaps the biggest disadvantage to AIX users accustomed to the speed of LANs
is the performance of X.25 networks. X.25 usually operates on transmission
media that are slower than LANs. In addition, the response time is not
predictable. The inconsistency of response time is most evident with interactive
applications such as the TCP/IP telnet command. For more information on
performance see Chapter 10, “Performance and Tuning” on page 219.
4
RS/0000 X.25 Cookbook
1.3 Components of a PSDN: DSEs, DTEs and DCEs
The terms DTE, DCE and DSE are used here as X.25 functional concepts.
Unfortunately, the modem world also uses this terminology with a slightly
different meaning, which sometimes causes confusion. We will be using the
CCITT-defined X.25 terminology.
The CCITT has defined the following terminology:
•
A switching node in a packet-switched data network is called Data-Switching
Equipment (DSE)
•
A computer that uses the network for communications is called
Data-Terminal Equipment (DTE)
•
A device at the point of access to the network is called Data
Circuit-terminating Equipment (DCE)
Every DTE must have an associated DCE.
Note: As DTE and DCE are functional definitions, they need not correspond to
specific items of equipment. For example, a single device may be a DSE
and may also provide multiple DCE interfaces.
While X.25 is a standard network-access protocol, it is not a complete end-to-end
protocol. The CCITT Recommendation X.25 defines a standard protocol for
information exchange in packet mode between a DTE and a DCE (that is,
between an individual user′s equipment, such as a RISC System/6000, and the
network provider′s equipment). X.25 does not define the network; the network is
often drawn as a cloud because the exact configuration and internetworking vary
from network to network. They are implementation dependent.
The network is composed of DCEs and DSEs that route the packets of data
through the network to the intended destination. The path that a user′s data will
take through the cloud might vary with every packet. All the user knows is that
the data goes from their DTE into the DCE, and that it arrives at the other end in
the correct order.
Operation and maintenance of DCEs and DSEs is the responsibility of the
network provider. If a link between two DSEs goes down, the provider must
reroute traffic. X.25 does not define the route through the network or the
protocols employed within it.
Figure 2 on page 6 shows the elements of a packet-switched data network.
Chapter 1. An Introduction to the X.25 Protocol
5
Figure 2. An X.25 Network
1.4 The Three Levels of X.25
The Open System Interconnection (OSI) reference model of the International
Standards Organization (ISO) defines a 7-layer model to specify how networks
work.
Levels one to three are network specific and differ depending on the physical
network used. Levels four to seven are network independent. These are the
higher-level functions. The X.25 protocol corresponds to the three
network-specific layers.
6
RS/0000 X.25 Cookbook
Figure 3. OSI, X.25 Layers
1.4.1 Physical Level
The physical layer is responsible for the transmission of raw bits of data across
some physical medium. In the X.25 protocol, the physical level activates,
maintains, and deactivates the physical circuit between a DTE and a DCE. The
AIX X.25 LPP implements the physical level as a STREAMS driver; the physical
layer performs the following functions:
•
Maintains line characteristics of the selectable interface
•
Indicates faulty incoming HDLC frames, such as frames with the wrong
length
•
Allows configuration of auto call units (ACU) for systems with dial-up X.25
connections
The physical level is defined in CCITT Recommendation X.21 and in CCITT
Recommendations X.21 and X.21bis . CCITT Recommendation X.21bis defines the
V.24 or V.35 interface between a DTE and a DCE.
The physical characteristics are divided into four distinct categories: physical,
electrical, functional, and procedural. The terms used for each kind of interface
in the LPP are V.24, V.35 and X.21:
V.24
stands for V.24 + V.28 + ISO 2110
V.35
stands for V.24 + V.35 + ISO 2593
X.21
stands for X.21 + V.11 + ISO 4903
V.24 (X.21bis) and X.21 are functional recommendations which define the use of
each pin. For instance, in the V.24 recommendation, the Clear To Send (CTS) is
the number 106, pin 5.
V.28, V.35 and V.11 are electrical recommendations which specify the electrical
levels. For instance, in V.28 recommendations, the logical state of each signal is
represented by a voltage transition in either the positive or negative
direction:+3V < binary 0 < +15V and -3V > binary 1 > -15V.
Chapter 1. An Introduction to the X.25 Protocol
7
ISO 2110, ISO 2593 and ISO 4903 are the physical recommendations which
describe the mechanical aspects of the connectors. ISO 2110 is a DB-25
connector, ISO 2593 is a DB-34 connector and ISO 4903 is a DB-15 connector.
1.4.2 Link Level
The X.25 frame level is equivalent to the OSI Data Link Level.
1.4.2.1 Purpose of this Layer
The packet layer produces X.25 packets to establish calls and transfer data. All
these packets are then passed to the frame layer for transmission to the local
DCE.
The X.25 recommendation for link level or frame layer describes the procedures
for data interchange between a DTE and a DCE. The procedures are regrouped
into three categories: link initialization/disconnection, error control and flow
control. The aim is to ensure an orderly and reliable exchange of information
under any of the variety of conditions that can affect a link.
The link level uses a link access procedure to ensure that data and control
information are accurately exchanged over the physical circuit between the DTE
and DCE. Its provides recovery procedures and is based on a subset of the
high-level data-link control (HDLC) called LAP_B. This procedure is synchronous
and full-duplex. Once a link is started, either station can transfer information on
its own initiative without waiting for permission from the other.
In HDLC, all commands, responses and data are transmitted in frames . Each
frame has a header containing address and control information, as well as a
trailer containing a frame-check sequence.
1.4.2.2 Types of Frames
There are three types of frames:
•
I (information) frames transfer user data. I_frames are numbered
sequentially. All X.25 packets are transferred within I_frames.
•
S (supervisory) frames supervise the link performing such functions as:
−
Acknowledging I_frames
−
Requesting retransmission of I_frames
−
Requesting temporary suspension of transmission of I_frames
S frames are numbered sequentially.
•
U (unnumbered) frames describe the mode of operation, for example, Set
Asynchronous Balanced Mode (SABM).
1.4.2.3 More about the Frames
Frames are made up of several fields:
Frame address: X.25 uses HDLC only in point-to-point mode, so the address
field is used only to separate link commands from responses. The field address
is set to 01 to identify frames containing commands from a DTE to a DCE and
responses to these commands from a DCE to a DTE. The field address is set to
03 to identify frames containing commands from a DCE to a DTE and responses
from a DTE to a DCE.
8
RS/0000 X.25 Cookbook
Poll/Final bit (P/F bit): The Poll bit (P) is used by the sender to insist on an
immediate response. This same bit becomes the receiver′s Final bit (F). The
receiver always turns the Final bit on in its response to a command from the
sender with the Poll bit set. The P/F bit may be used when either end becomes
unsure about proper frame sequencing, perhaps from a missing
acknowledgement, and wants to re-establish a point of reference.
Send and Receive Counters: I_frames are assigned independent pairs of
sequence numbers that operate in both send and receive directions to ensure
that no frames are lost or interpreted out of order. The N(S) counter is
incremented each time a frame is sent, and the N(R) counter is incremented
each time a frame is received. These counters are ranged from 0 to 7 (modulo 8)
or 0 to 127 (modulo 128).
Figure 4. HDLC Frame Structures
For more information on frame control fields, see 4.2, “The x25mon Tool” on
page 79.
1.4.3 Packet Level
The X.25 packet layer is equivalent to the ISO network level.
1.4.3.1 Role of the Packet Layer
The packet layer is the most complex layer of the three layers which compose
the X.25 protocol. This complexity is a result of the designed-in flexibility and the
reliable nature of the packet layer protocol. As the X.25 protocol is
connection-oriented, the primary function of this layer is to give users access to
the network by establishment of a connection, in the form of virtual circuit.
The packet level protocol specifies how virtual circuits between DTEs are
established, maintained and cleared. This level defines how a single physical
channel (the access link) can be treated as a set of multiple logical channels,
each providing a virtual circuit. It also defines the structure of data packets and
Chapter 1. An Introduction to the X.25 Protocol
9
control packets used to establish and manage a virtual circuit between two DTEs
in a PSDN.
The recommendations for the packet level are not as specific as those for the
physical and link levels, and they allow network providers some freedom in
implementing the packet functions. For example, some networks do not support
the Diagnostic Code field in the Reset and Clear Indication packets.
The X.25 packet level includes the following functions:
Multiplexing
Supports multiple concurrent connections
Data Transfer
Sends and receives data
Interrupt Transfer
Sends and receives a small amount of information independent of the
data stream
Error Control
Detects packet level errors
Reset and Restart
Reinitializes communication paths if packet level errors occur
1.4.3.2 X.25 Packet Types
Different types of packets are used for such purposes as making a call,
accepting a call, transferring data and terminating a call. The X.25
communications software does most of the work involved in creating the
packets. You do not have to know the detailed content of each packet; you only
have to supply the information that is needed to create the packet.
In some circumstances, the contents of the packet when it reaches the called
DTE are different from when it left the calling DTE. This is because some
information is different for each DTE (for example, logical channel number), or
only applicable to one DTE, or it is information inserted by the network.
Packets are grouped into the following categories:
•
Call establishment and clearing
CALL_REQUEST
INCOMING_CALL
CALL_ACCEPTED
CALL_CONNECTED
CLEAR_INDICATION
CLEAR_REQUEST
CLEAR_CONFIRMATION
•
Data and interrupt
DATA
INTERRUPT
INTERRUPT_CONFIRMATION
•
Flow control and reset
RESET_REQUEST
RESET_INDICATION
RESET_CONFIRMATION
10
RS/0000 X.25 Cookbook
RECEIVE_READY
RECEIVE_NOT_READY
•
Restart
RESTART_REQUEST
RESTART_INDICATION
RESTART_CONFIRMATION
DIAGNOSTICS
Some of the most common control packet exchanges are:
┌──────┐ Call Request
┌──┬────────────┬──┐ Incoming Call
┌─────┐
│
1├───────────────────│ D│
│D ├─────────────────│2
│
│ DTE │
│ C│
PSDN
│C │
│ DTE│
│
4│───────────────────┤ E│
│E │─────────────────┤3
│
└──────┘ Call Connected └──┴────────────┴──┘ Call Accepted └─────┘
Figure 5. Establishing a Switched Virtual Circuit
┌──────┐ Clear Request
┌──┬────────────┬──┐
┌─────┐
│
1├───────────────────│ D│
│D │ Clear
│
│
│ DTE 2│───────────────────┤ C│
PSDN
│C │ Indication
│ DTE│
│
│ Clear
│ E│
│E ├─────────────────│3
│
│
│ Confirmation
│ │
│ │─────────────────┤4
│
└──────┘
└──┴────────────┴──┘ Clear
└─────┘
Confirmation
Figure 6. Clearing a Switched Virtual Circuit
┌──────┐
Reset Request
┌──┬────────────┬──┐
│
1├─────────────────────────│ D│
│D │
│ DTE │
│ C│
PSDN
│C │
│
2│─────────────────────────┤ E│
│E │
└──────┘
Reset Confirmation └──┴────────────┴──┘
Figure 7. DTE Initiated Reset
┌──────┐
Reset Indication
┌──┬────────────┬──┐
│
1│─────────────────────────┤ D│
│D │
│ DTE │
│ C│
PSDN
│C │
│
2├─────────────────────────│ E│
│E │
└──────┘
Reset Confirmation
└──┴────────────┴──┘
Figure 8. DCE Initiated Reset
1.4.3.3 More Details on the Packets
Packets are made up of several control fields and user data.
More-bit (M bit): Data sent during a call is divided into units. The size of these
units is the packet size . Packet size applies to the size of the data packets, not
all packets. The default packet size is 128 bytes. When one unit of data that is
greater than the packet size needs to be sent, a number of packets is sent. The
M bit is set to 1 to inform the destination DTE that more data will follow in the
next packet. Thus, packets can be logically chained together to convey a large
block of related information. Packets with the M bit set are always full. The last
packet in the chain has the M bit set to 0, indicating that the series is completed.
Chapter 1. An Introduction to the X.25 Protocol
11
The M bit can also be used to match unequal packet sizes at the DTE/DCE
interface on either side of the network.
Delivery-bit (D bit): The D bit is normally set to 0 to indicate that the packet
layer acknowledgments have only local significance between one DTE and DCE.
When set to 1 in a call setup or data packet, the D bit indicates that
acknowledgments have end-to-end significance between source and destination
DTE. The D bit may be turned on and off selectively on a per-packet basis.
The use of the D bit increases overall network traffic.
Qualifier bit (Q bit): The data qualifier bit indicates the kind of data carried by
the packet. A Q bit set to 0 means that the packet carries conventional user data.
A Q bit set to 1 means that the packet carries control information and the packet
should be interpreted differently by the called DTE. The use of this bit is only
standardized with X.29 control packets used by the asynchronous PADs.
User Data (UD): The final field of a packet is the user data field. The use and
length of this field is determined by the Packet Type Identifier.
Counters: The packet layer has its own send and receive counters, P(S) and
P(R), that operate independently of the Data Link Level counters, N(R) and N(R).
These counters are used for level 3 window control.
Figure 9. Packet Format
For more information on packet format, see 4.2, “The x25mon Tool” on page 79.
1.5 Network User Address (NUA)
On an X.25 network, each system (DTE) is identified by an address supplied by
the network provider. This address is called network user address (NUA). To
ensure unique DTE addressing worldwide, X.121 defines an international
numbering scheme. Most public networks use the X.121 addressing standard to
create NUAs.
Under the X.121 addressing standard, the network user address is built by:
•
12
RS/0000 X.25 Cookbook
Data Network Identification Code (DNIC), which is four digits long:
−
Data Country Codes (DCC)
- First digit to identify a world geographic zone
- Second and third digits to identify a specific country
−
Fourth digit for specific Public Data Network
The number of PDNs within the U.S. exceeded the limit of 10, so the CCITT
has granted the U.S. the use of the last two digits of the DNIC as the PDN
identifier.
•
National Terminal Number (NTN): Following the DNIC are 10 digits assigned
by the PDN. When a communication is made within a given network, the NTN
is often used as the NUA. The DNIC is usually used when the remote system
is on a different network from the calling system. There is no rule of how
NTNs should be built. However, most PDNs leave the last 2 digits as an
optional subaddress to allow the X.25 subscriber to manipulate these two
digits for their own applications. This subaddress is not processed by the
PDN and can be used to identify a finer granularity of address on the remote
system.
The following figure shows the structure of the network user address (NUA),
leaving two digits for the subaddress.
┌─────────────────┬──────────────────────┬─────────────────────┐
│ Data Network │
National Terminal │ Optional Subaddress │
│ Identification │
Number
│
│
├─────────────────┼──────────────────────┼─────────────────────┤
│
1234
│
56789012
│
34
│
└─────────────────┴──────────────────────┴─────────────────────┘
Figure 10. Network User Address (NUA) Structure
The X.121 addressing standard also defines a one-digit optional prefix for use on
international calls:
•
If a call is beyond PDN boundaries, a 0 or 1 is added at the beginning of the
NUA.
•
If a call is within PDN boundaries, no prefix is added to it.
The maximum length of an NUA is 15 digits.
1.6 Logical Channels and Virtual Circuits
Communications in X.25 networks are via logical channels and virtual
connections.
1.6.1 Definition
An AIX X.25 adapter provides one or more physical connections to the network.
Each physical connection supports multiple, concurrent logical connections
( virtual circuits ) to other DTEs on the network. A virtual circuit is a data circuit
between the local and remote system, which may have its route switched within
the network. Logical channels are the conversation paths between a DTE and its
DCE.
Chapter 1. An Introduction to the X.25 Protocol
13
1.6.2 Logical Channel
The number of concurrent connections possible depends on the number of
logical channels the network provider defines and the capabilities of the DTE
hardware and software. To have 15 simultaneous connections across a network,
the network supplier must provide 15 logical channels. Valid logical channel
numbers range from 1 to 4095 (logical channel number 0 typically is reserved for
diagnostics). The network provider assigns the specific logical channel
numbers, and each number must match between the DTE and its DCE; a DTE
using logical channels 51-58, for example, could not communicate with a DCE
using logical channels 3002-3009. However, when a DTE talks with another DTE
across a PSDN network, the DTE logical channel numbers do not have to match.
The logical channel is not end-to-end in the network; it must only match between
each DTE/DCE pair, as shown in Figure 11.
1.6.3 Virtual Circuit
When a user application initiates a conversation with another DTE on the
network, a virtual circuit is established from one DTE to the other via the DCEs
on the network. This virtual circuit only exists for the duration of the call. When
the conversation is over, the virtual circuit is closed. The logical channel is then
free to be allocated to another application. Each application running between
two hosts requires a virtual circuit.
1.6.4 Multiplexing
With AIX, once the virtual circuit has been established between two machines for
TCP/IP, all TCP/IP traffic between those two machines will flow on this single
virtual circuit. The same is true for SNA on the RISC System/6000. This
multiplexing of traffic helps lower the number of logical channels users need,
reducing networking costs.
Figure 11. Logical Channels and Virtual Circuits
14
RS/0000 X.25 Cookbook
1.6.5 Types of Virtual Circuits
X.25 defines two basic types of virtual circuits: Permanent Virtual Circuits (PVCs)
and Switched Virtual Circuits (SVCs). PSDN networks allow users to establish a
PVC between two DTE addresses to save time in establishing calls. It is like
having a leased line, a permanent telephone call connected, just in case you
want to say something. PVCs are much less flexible than SVCs because they tie
up a logical channel permanently, cost more and cannot (according to the
CCITT) span different PSDN networks. This means, for example, users could not
establish a PVC outside their own country. For these reasons, SVCs are much
more common.
SVCs need three distinct phases for the connection establishment: call setup,
data transfer and call clearing; while PVCs require only the data transfer phase.
SVCs are virtual circuits that exist only for the duration of the call, acting like a
connection over the normal telephone network. For SVCs, there are three types
of logical channels:
•
Incoming: The DTE can only receive calls on this channel
•
Outgoing: The DTE can only initiate calls on this channel
•
Two-Way: The DTE can both receive and make calls on this channel
These channel types are used only for call initiation. Once a virtual circuit has
been established, it is always for two-way communication. Typically, one or two
types of SVCs are used, depending on security requirements. However, if more
than one type is used, in order to minimize call collisions, the CCITT states that
the logical channel numbers must be assigned within the following hierarchy,
from the lowest logical channel number to the highest:
•
•
•
•
PVC
Incoming SVCs
Two-way SVCs
Outgoing SVCs
Two-way SVCs are the most common types of virtual circuits, as they offer the
greatest flexibility and
least administration by allowing both incoming and outgoing calls. One-way
incoming SVCs may be used for security reasons.
1.7 Facilities
Facilities allow the subscriber greater control of the X.25 environment. Their
availibilty is optional and determined by the network provider.
1.7.1 Definition
In order to offer flexibility, X.25 recommendations define a rich set of optional
user facilities. These facilities allow a network planner to fine-tune the network′ s
handling of such major areas as security, accounting, routing and performance.
The X.2 recommendations define more than 30 International User Services and
Facilities in Public Data Networks. The X.25 recommendations define only the
facilities related to packet-switched Public Data Networks. So at each call setup
time, users may request special network services beyond normal default
offerings by using the optional user facilities.
Chapter 1. An Introduction to the X.25 Protocol
15
Some facilities are standard; other, optional facilities must be subscribed to by
the users as a part of their contract with the network provider. The ability to
negotiate the packet size, for example, is a standard facility on almost all the
networks, while reverse charging acceptance is optional and must be allowed in
the network subscription.
Some optional facilities, when included in the user subscription, are valid for all
virtual calls. The reverse charging acceptance is an example of such a facility
and is in effect for all incoming calls. Other facilities, such as reverse charging ,
must be specifically requested for the duration of a call.
The facilities and their coding are defined in the CCITT Recommendation X.25
sections 6 and 7. The ones you can actually use are defined in your X.25
subscription.
1.7.2 Use of Facilities
Call time facilities: To use a facility valid for the duration of a virtual call, a
facility request specifying the nature of the facility and the corresponding
parameters must be inserted in the call packet. The X.25 application on the RISC
System/6000 (DTE) can insert a facility request either in the call request (calling
DTE) or call accepted (called DTE) packet. Coding of the facilities is the
responsibility of the application developer and not the device driver or X.25
microcode.
The network (DCE) can also notify the DTE of the use and parameters of a
facility. In this case, the DCE inserts a facility indication either in the incoming
call or call connected packet. Figure 12 shows the name of the different call
packets.
┌───────────┐
┌──────────────────┐
┌───────────┐
│
│
│
│
│
│
│
│ Call request
│
│
Incoming call
│
│
│
├──────────────────────│
├────────────────────────│
│
│
│ Facility request
│ X.25 Network │ Facility indication │
│
│
│
│
│
│
│
│ Calling │
│
Called
│
│
│
│
DTE
│
│
DCE
│
│
DTE
│
│
│
│
│
│
│
│
│ Call connected
│
│
Call accepted
│
│
│
│──────────────────────┤
│────────────────────────┤
│
│
│ Facility indication │
│
Facility request
│
│
│
│
│
│
│
│
└───────────┘
└──────────────────┘
└───────────┘
Figure 12. Facilities and Call Packets
Coding and decoding facilities: Figure 13 on page 17 shows the structure of a
call packet. Call request, incoming call, call accepted and call connected packets
all have the same structure.
16
RS/0000 X.25 Cookbook
Figure 13. Call Packet Formats
The facility requests or facility indications are inserted between the address
block and the CUD (Customer User Data) and are prefixed by an octet containing
the total length of the facilities. Appendix E, “Facilities” on page 275 explains
how to code or decode facilities.
1.7.3 Types of Facilities
The following table lists the main facilities that may be requested for the duration
of a call either by the DTE or DCE.
See Appendix E, “Facilities” on page 275 for an exhaustive list of the facilities
available with X.25.
Table 1. X.25 Optional Facilities
Optional facilities
1980
Req
Ind
Throughput class selection
y
y
y
Flow-control parameters selection
y
y
y
CUG selection
*
y
Reverse charging
y
y
y
Fast select
y
y
y
Recognized Private Operating Agency (RPOA) selection
y
y
Network user identification (NUI)
y
Call redirection notification
y
Charging requesting service
Note:
y
* Basic CUG only in CCITT 1980.
Throughput class negotiation The throughput class negotiation, when it is
subscribed to, allows you to change your default throughput class
(measuring the transmission speed within the network) to a lower
value. This does not affect the DTE-to-DCE speed, only the speed at
which a packet traverses the switching nodes in the network. If both
the calling DTE and the called DTE have subscribed to this facility, the
Chapter 1. An Introduction to the X.25 Protocol
17
mechanism to select the throughput class that will be used during a
virtual call is the following:
1. The calling DTE requests a throughput class for both directions of
traffic with a throughput class facility request in the call request
packet, or it implicitly chooses the default values. The requested
value must be lower than the default.
2. The DCE will indicate to the called DTE in the incoming call
packet the throughput class which will be the lowest value among:
a. The default throughput class, subscribed to by the calling DTE
b. The throughput class requested by the calling DTE
c. The default throughput class subscribed to by the called DTE
3. The called DTE may accept the proposed value if it is lower than
its default or may request, with a facility in the call accepted
packet, a throughput class that is lower than the value from the
incoming call.
4. Finally, the value chosen for the throughput class is indicated to
the calling DTE in the call connected packet.
Flow-control parameter negotiation The flow-control parameter negotiation is the
determination of the packet size and packet window size that will be
agreed upon by the DTE and the DCE for a given call. When two
DTEs are communicating through an X.25 network, the flow-control
parameters on the side of the calling DTE and on the side of the
called DTE are completely independent. For example a DTE A can
use a packet size of 256 and a window size of 4 and communicate
successfully with a DTE B operating with a packet size of 1024 and a
window size of 2.
When the network supports flow-control parameter negotiation, the
incoming call packet will contain the packet size and the window size
from which the negotiation will start.
By default (that is, if you do not change the default parameters) the
packet size used for the call will be determined as follows:
•
If the size proposed in the incoming call is within the limits of the
maximum and minimum packet size, it is accepted.
•
If the size proposed is larger than the maximum size defined in
the DTE, there will be a negotiation, and the DTE will send a
facility request in the call accepted packet accepting a packet size
equal to the maximum.
The window size determination is done the same way as the packet
size. If the value proposed in the incoming call packet is acceptable
to the DTE, it is used. If it is not, the DTE negotiates an acceptable
value by using a window negotiation facility request in the call
accepted packet.
Closed User Group (CUG) A closed user group (CUG) is a facility that allows a
user to collect a number of DTEs into a single logical group. Access
to the group may be restricted to receiving incoming calls from
and/or making outgoing calls to the unrestricted open portion of the
network. So a member of one subgroup may be allowed to
communicate only with other members of the same subgroup. A
public network supports up to 99 CUGs for a single DTE; an extended
18
RS/0000 X.25 Cookbook
CUG format allows up to 10,000 CUGs. The CUG selection facility
allows the DTE to specify what CUG it will be working with. It appears
in the incoming call packet to identify to the called DTE which CUG
has been selected.
Reverse charging option Reverse charging allows a DTE to request that the cost
of a call it makes be charged to the called DTE.
Fast select option Fast select means the user has 128 bytes of call user data
instead of the ordinary 16. Also, 128 bytes may be sent in the call
accepted packet. Fast select must be enabled at subscription time for
that particular DTE. With it, you can make applications that depend
entirely on the virtual call protocol, clearing virtual circuits as soon as
calls come in.
RPOA selection With the RPOA selection facility, you can select one or several
specific transit networks to carry your virtual circuit. RPOA stands for
Recognized Private Operating Agency, the CCITT′s term for a
gateway carrier between PDNs. When making internetwork or
international calls, RPOA Selection in the call request packet allows
the DTE to specify a particular transit network (gateway), when more
than one exists. No attempt at alternate routing is made if the call
cannot be successfully routed through the transit-network gateway.
An extended version of this facility permits the selection of more than
one RPOA transit network.
Network user identification Network User Identification (NUI) allows the
requesting DTE to provide billing, security or management information
on a per-call basis to the DCE.
Call redirection notification The call redirection notification informs the caller that
the call has been redirected to another DTE.
Charging requesting service Charging requesting service specifies that charging
information (segment count data, monetary unit data or call duration
data) is required.
1.8 X.25 Network Subscription
The network supplier must give some information about the connection before
the users can connect to the network. The network provider assigns the DTE
address (NUA), the logical channel numbers and the types of virtual circuits.
There are many more attributes that must match between the DTE and the
network′s DCE.
The network supplier provides the X.25 attachment attributes that must be used
for DTE configuration in the network subscription. Suppliers create subscriptions
based on their network conventions, DCE hardware and customers′
requirements (performance, number of concurrent connections, security needs
and so on). The network attachment speed and the DCE hardware will
determine the modem cable interface, so customers should check with the
network provider before ordering cables.
To configure an AIX DTE, the network provider should be told that the X.25
device driver expects the following attachment characteristics:
•
Full-duplex, synchronous transmission
•
Leased-line attachment or dial-up capability through X.32
Chapter 1. An Introduction to the X.25 Protocol
19
•
Network or modem-provided clocking
AIXlink/X.25 Version 1.1.3 supports CCITT up to 1988.
One RISC System/6000 may have several X.25 physical connections or ARTIC
Portmaster/A, and each connection requires a network subscription. The network
supplier may provide automatic call rerouting (when a port is busy) as part of
the subscription.
1.9 Summary of IBM Support Experiences
Users with experience in X.25 networking find that configuring the X.25 network
attachment on AIX hosts is familiar and easy. The following comments will be
helpful to users who have no previous experience with X.25.
The IBM country support centers have been involved in hundreds of X.25
installations around the world since the general availability of AIX Version 3.1 in
July 1990. While each situation has been unique, some similarities have been
observed.
Compared to the traditional modem and LAN connectivity methods, X.25
problems often take weeks rather than days to resolve. Lack of knowledge and
inexperience with X.25 has been the cause of problems in the majority of cases,
thus creating a misconception of the project. AIX systems administrators tend to
assume X.25 is like a token-ring or Ethernet LAN, when it is more analogous to
SNA, VTAM or NCP. This misconception is understandable. Most AIX systems
administrators work with LANs every day and have developed great skill in
software, hardware and troubleshooting.
X.25 is more complex than LAN. On the RISC System/6000, there are roughly 100
parameters that users or systems administrators can configure (or misconfigure)
with the system management interface tool (SMIT). Sometimes, a single
attribute can make the difference between success and failure.
1.9.1 Planning Considerations
Organizations considering using X.25 can take the following steps to ensure as
smooth an installation as possible. Understanding the scope of the task,
planning appropriately and setting the proper expectations can make all the
difference.
•
Learn about X.25 Ask questions and, if possible, get some hands-on
self-education.
•
Plan Define applications and select them carefully. Make sure everybody
understands the interdependencies.
•
Set realistic installation time expectations Allow plenty of time to correct
errors.
•
Subscribe to a network Find a contact at the network provider and get them
involved in the planning process.
•
Take the installation in stages Get each stage working before moving to the
next. When finished, make a backup of the parameters that work.
Subscribing to a real PSDN network is key to a successful X.25 installation.
While the back-to-back method (described in Chapter 3, “X.25 LPP Installation
20
RS/0000 X.25 Cookbook
and Setup” on page 43) is useful for early testing, it fails to provide an ongoing
production solution. The link startup procedure would be cumbersome, and X.25
packets would add overhead, thereby reducing data throughput.
It is unrealistic for the X.25 novice to expect to set up any X.25 connection in one
day. The X.25 attributes set in the SMIT menus are critical to success, and
working out mismatches with the network can take some time. Good planning
and communication between all parties can reduce installation time dramatically.
It is helpful to establish a contact who can speak for the DCE configuration early
in the planning cycle. Only the network provider can advise users on the
parameters that must be set in the SMIT menus.
The installation should be done in stages. Using the x25mon command, users can
isolate frame- and packet-level problems. However, the display rate must keep
up with the rate of data received. For an ASCII terminal, users should redirect
x25mon output to a file.
Once successfully connected to the network, users should save a copy of the
X.25 SMIT configuration. To assure complete recovery from a failure, users must
also note any changes to xroute and the applications they are using.
1.9.2 Application Selection
Many AIX systems administrators want to view X.25 WANs as giant LANs. It is
unrealistic to expect LAN performance from X.25 networks. Yet performance is
usually sufficient for all but interactive or high-throughput applications. X.25
networking is best for batch applications. Mail exchange and order inquiry are
good examples. X.3, X.28 and X.29 (collectively called Triple X ) also provide very
practical solutions. For example, corporations with retail stores and branch
offices use Triple X to make casual inquiries to the central site. Triple X allows
them to put low-cost terminals and printers, or PCs and workstations running an
asynchronous terminal emulation program, at outlying locations. To the users
performing casual order entry, queries or mail, the attachment appears to be
permanent. In reality, the network is accessed only as needed. At the central
site host, the data is processed as if the terminal were attached to a local serial
port.
X.25 networking does not suit highly interactive or time-critical applications, or
those that involve extremely high volumes of data. Examples of these
applications include transfer of large graphics files, network installation, Network
File System (NFS), X-Windows and extensive use of telnet. With X.25, users are
charged for the number of packets sent. The cost of transmitting the AIX
operating system across the network in chunks of 128 bytes would be prohibitive,
and the transfer would be slow. With telnet, packets often contain a single
character, so the cost of editing a file across the network would be considerable.
It would be better to use ftp to transfer the file to the local system, edit it and
then use ftp to return the new copy. For these types of applications, users
should bridge the LAN with a product like IBM′s Token-Ring Remote Bridge.
Leased lines can connect sites at speeds up to 1.33 Mbps, giving AIX users the
needed bandwidth.
Finally, it is important to consider the number of concurrent users needing
support over X.25 (as this will be the number of logical channels needed in the
network subscription) and what they will be doing once they log in. Would the
machine you intend to use support them if they were locally attached?
Chapter 1. An Introduction to the X.25 Protocol
21
Interactive applications use CPU resources heavily. Please refer to 10.5,
“Applications” on page 221.
22
RS/0000 X.25 Cookbook
Chapter 2. RISC System/6000 X.25 Support
In this chapter, we will describe the functions provided by and AIXLink/X.25
Version 1.1.3 licensed program products.
2.1 RISC System/6000 Functions Summary
AIXLink/X.25 Version 1.1.3 is supported on AIX Version 4.1.4 and Version 4.2.
Other X.25 products are available from IBM for earlier versions of AIX.
Summary of the X.25 LPP support on the RS/6000
 Copyright IBM Corp. 1996
•
Complies with the CCITT 1988 X.25 Recommendations
•
Supports up to 8 X.25 adapters per system
•
Supports Micro Channel and ISA bus adapters
•
Provides X.3, X.28 and X.29 Packet Assembler/Disassambler (PAD) supp
ort
•
Supports PAD printing
•
Provides SNMP support for data items from the MIBs for the packet and
frame layers
•
Provides the NPI packet layer programming interface
•
Provides the DLPI frame layer programming interface
•
Provides a compatible API for applications written to the X.25
support included in AIX Version 3
•
Provides dedicated or switched (X.32, V.25 bis) network access
•
Allows automatic or user-defined point-to-point DTE/DCE configuration
•
Provides applications for messaging, file transfer, link status and line
monitoring
•
Supports TCP/IP
•
Supports SNA LU 0, 1, 2, 3 and 6.2
•
Supports up to 512 logical channels per line
•
Physical interface can be V.24, V.35, V.36 or X.21
•
Supports speeds up to 2 Mbps, depending on the physical link
•
Supports several IBM communications adapters
•
Priced by number of virtual circuits, not processor group
.
23
Supported Adapters
•
•
ARTIC Portmaster Adapter/A (FC 7006/7008)
−
Micro Channel
−
1MB - FC 7006
−
2MB - FC 7008 (supported, but no longer available)
−
8 Ports - V.24 interface
−
6 Ports - V.35 or X.21 Interface
ARTIC Mulitport Model II (PS/2 FC 6590/5306*)
Note: *PS/2 FC 5306 is used when ordering in EMEA.
•
•
•
−
ISA
−
8 Ports - V.24 interface
−
6 Ports - V.35 or X.21 Interface
X.25 Interface Co-Processor/2 - FC 2960
−
Single Port V.24/V.35/X.21
−
Micro Channel
X.25 Interface Co-Processor - FC 6753
−
Supported by AIXLink X.25 for AIX Version 4.x ONLY
−
Single Port V.24/V.35/X.21
−
ISA
ARTIC960 Adapter - FC 2929/2935/2938
−
Supported by AIXLink X.25 V1.1.3 or higher
−
Micro Channel
−
8 port - V/24 (128 Kbps)
−
6 port - V.36 (2 Mbps)
−
6 port - V.35 (64Kbps)
−
8 port - X.21 (2Mbps)
Note: The IBM X.25 Interface Co-Processor and X.25 Interface
Co-Processor/2 provide equivalent function on RISC/6000 models
with different I/O bus architectures. These adapters have identical
pin assignments and attach with identical cables.
AIXLink/X.25 Version 1.1.3 is available and priced by number of virtual circuits:
Virtual Circuit Ordering Option
24
RS/0000 X.25 Cookbook
•
AIXLink/X.25 Entry Level Capacity (Up to 4 Virtual Circuits)
•
AIXLink/X.25 Basic Capacity (Up to 16 Virtual Circuits)
•
AIXLink/X.25 Extended Capacity (17 to 64 Virtual Circuits)
•
AIXLink/X.25 Advanced Capacity (65 to 256 Virtual Circuits)
•
AIXLink/X.25 Unlimited Capacity (257 Virtual Circuits and above)
On a system running AIX V 4.x, the X.25 LPP requires the virtual circuit license
information (see 3.3, “Software Customization” on page 52).
2.1.1 Number of Virtual Circuits Supported
The maximum number of virtual circuits supported is 512 per port. The realistic
number of virtual circuits will be determined by several factors:
•
Number of adapters per system
Note: Maximum number of adapters is determined by supported hardware
configurations.
•
Number of ports per adapter, 1 - 8
•
Licensing option, AIXLink/X.25 for AIX 4.x
•
Packets per second per adapter, 200 128byte packets/sec/adapter
•
Acceptable performance, see Chapter 10, “Performance and Tuning” on
page 219
•
Recommended Number of Virtual Circuits is 1024 per adapter
2.2 RISC System/6000 X.25 Components
To participate in an X.25 network, the RISC System/6000 requires a number of
components.
2.2.1 IBM X.25 Interface Co-Processor and Co-Processor/2
As stated before, the two adapters are functionally equivalent with different I/O
bus interfaces.
The X.25 adapter design conforms to the ISO 8208 standard which is compatible
with the CCITT 1980, CCITT 1984 and CCITT 1988 recommendations.
The IBM X.25 Interface Co-Processor(/2) provides support for attaching a RISC
System/6000 unit to an X.25 network. The adapter provides a single port that will
accommodate three selectable interfaces: X.21, EIA-232D/V.24 and V.35. The port
has a 37-pin female D-shell connector.
The X.25 Interface Co-Processor(/2) features the following:
•
•
•
Full-duplex, synchronous protocol
Support for the following interfaces:
− X.21 interface at up to 64 Kbps
− EIA-232D/V.24 interface at up to 19.2 Kbps
− V.35 interface at up 56 Kbps
Wrap plug for 37-pin connector supplied for testing
Feature codes for the X.25 Co-Processors are:
•
For Micro Channel: Feature Code #2960
•
For ISA Bus: Feature Code #6753
Chapter 2. RISC System/6000 X.25 Support
25
X.25 Co-Processor FC #6753
The Co-Processor for ISA bus has switches to set the adapter interrupt level.
Refer to the adapter and system unit reference manuals to determine a valid
level for your installation.
Realtime Control Microcode (RCM)
The Realtime Control Microcode is now delivered as part of the X.25 LPP and
is no longer a separate installation. The RCM diskette is no longer needed.
The following figure illustrates the different configurations of the IBM X.25
Interface Co-Processors with each kind of cable:
Figure 14. IBM X.25 Interface Co-Processors
2.2.2 IBM ARTIC Portmaster Adapter/A
The IBM Realtime Interface Co-Processor Portmaster Adapter/A, with 1MB
(#7006) or 2MB (#7008) of memory can be used to connect a RISC System/6000
unit to an X.25 network. The ARTIC Portmaster Adapter/A must be used with an
Electronic Interface Board (EIB) with the appropriate device interface cable
(fanout box).
Note: Feature code 7008 is supported but no longer available.
The IBM ARTIC Portmaster Adapter/A has the following characteristics:
26
•
Micro Channel.
•
12.5 MHz Intel 80186 microprocessor.
RS/0000 X.25 Cookbook
•
Adapter-to-adapter and adapter-to-system Micro Channel bus master
support.
•
Up to eight serial I/O ports (asynchronous or synchronous) available through
a family of interface boards and cables.
•
Performance up to 64 Kbps full duplex for each of eight ports running
concurrently.
•
Performance of up to 2.048 Mbps full duplex for single port. This throughput
is a maximum that the card is capable of achieving and is not supported by
AIXLink/X/25/.
•
Dynamically managed adapter storage.
Depending on the interface you are using to attach your system to the X.25
network, select one of the following interface boards and cables:
•
V.24 Interface:
−
−
−
•
V.35 Interface:
−
−
•
8-Port RS-232-D/CCITT V.24 Interface Board/A (#7042)
8-Port Cable (#7108)
FC 2939 can be used instead of the two above
6-Port V.35 Interface Board/A (#7046)
6-Port V.35 Cable (#7106)
X.21 Interface:
−
−
6-Port X.21 Interface Board/A (#7048)
6-Port X.21 Cable (#7110)
The following figure illustrates the different configurations of the IBM ARTIC
Portmaster Adapter/A with each kind of EIB, device interface and cable:
Chapter 2. RISC System/6000 X.25 Support
27
Figure 15. IBM ARTIC Portmaster Adapter/A Configurations
Note: The 4-port Multiprotocol Adapter is NOT supported for X.25
communications.
The Portmaster and Multiport adapters are functionally equivalent, and the EIBs
and cables are interchangeable.
2.2.3 IBM ISA Multiport Model II Adapter
This base adapter provides an ISA bus equivalent to the Portmaster/A Micro
Channel adapter solution supported in the original AIX X.25 LPP. In both cases,
the adapter consists of a base adapter with at least 1MB of memory and one of
the three daughter cards (Electronic Interface Boards or EIBs). The daughter
cards and corresponding interface cables are interchangeable between the
Micro Channel and ISA base adapters.
•
8 port V.24 (EIA 232)
•
6 port X.21
•
6 port V.35 connection
For V.24, the AIXLink V1.1.3 software supports speeds of up to 19.2 Kbps. For
X.21 and V.35, the connections are supported up to 64 Kbps. The Multiport
Model II (ISA) base adapter is NOT available using a RS/6000 order number.
Therefore, it can NOT be ordered through the normal RS/6000 channels and can
NOT be specified via the RS/6000 configurator. This base adapter MUST be
ordered through normal PC channels using the PS/2 order number, feature
28
RS/0000 X.25 Cookbook
#6590 for USA, Asia Pacific and Latin America, feature #5306 for EMEA. The
daughter cards and corresponding interface cables (fanouts) are interchangeable
between the Micro Channel and ISA base adapters. Daughter cards and fanouts
may be ordered under the RS/6000 or PS/2 feature codes. Modem cables, which
attach between the fanout and the modem or DSU/CSU, are also available
through either channel.
The IBM Realtime Interface Co-Processor Multiport Adapter Model II can be used
to connect a RISC System/6000 unit to an X.25 network. The ARTIC Multiport
Adapter Model II must be used with an Electronic Interface Board (EIB) with the
appropriate device interface cable (fanout box).
The adapter has the following characteristics:
•
ISA bus.
•
12.5 MHz Intel 80186 microprocessor.
•
Adapter-to-adapter and adapter-to-system Micro Channel bus master
support.
•
Up to eight serial I/O ports (asynchronous or synchronous) available through
a family of interface boards and cables.
•
Performance up to 64 Kbps full duplex for each of eight ports running
concurrently.
•
Performance of up to 2.048 Mbps full duplex for single port. This throughput
is a maximum that the card is capable of achieving and is not supported by
AIXLink/X.25.
•
Dynamically managed adapter storage.
Depending on the interface you are using to attach your system to the X.25
network, select one of the following interface boards and cables:
•
V.24 Interface:
−
−
•
V.35 Interface:
−
−
•
8-Port RS-232-D/CCITT V.24 Interface Board/A (PS/2 #6362 or RS/6000
#7042)
8-Port Cable (PS/2 #6366 orRS/6000 #7108)
6-Port V.35 Interface Board/A (PS/2 #1210 or RS/6000 #7046)
6-Port V.35 Cable (PS/2 # 1210 or RS/6000 #7106)
X.21 Interface:
−
−
6-Port X.21 Interface Board/A (PS/2 #1170 or RS/6000 #7048)
6-Port X.21 Cable (PS/2 #2028 or RS/6000 #7110)
Note: This adapter has switches to set the adapter interrupt level. Refer to the
adapter and system unit reference manuals to determine a valid interrupt
level for your installation.
The following figure illustrates the different configurations of the Multiport Model
II Adapter with each kind of EIB, device interface and cable:
Chapter 2. RISC System/6000 X.25 Support
29
Figure 16. IBM ARTIC Multiport Adapter Model II Configurations
Note: The electronic interface boards, interface cables and modem cables used
with the IBM ARTIC Portmaster Adapter/A, Figure 15 on page 28, may be
substituted for the PS/2 components.
2.2.4 IBM ARTIC960 Adapter
The IBM Realtime Interface Co-Processor ARTIC960 Adapter can be used to
connect a RISC System/6000 unit to an X.25 network.
Each Interface Co-Processor ARTIC960 Adapter is equipped with 4MB of memory
and an electronic interface board. Feature codes 2929, 2935 and 2938 will order
the adapter, 4M memory and V.24, V.36 or X.21 EIB, respectively. The ARTIC960
Adapter must be used with the appropriate device interface cable (octopus or
fanout box).
The IBM ARTIC960 Adapter has the following characteristics:
30
•
25 MHz Intel 80C960 microprocessor.
•
Adapter-to-adapter and adapter-to-system Micro Channel bus master
support.
•
Up to eight serial I/O ports (asynchronous or synchronous) available through
a family of interface boards and cables.
RS/0000 X.25 Cookbook
•
Performance up to 64 Kbps full duplex for each of eight ports running
concurrently on FC 2929.
•
Performance of up to 2.048 Mbps full duplex for all ports with FC 2935 and FC
2938. This throughput is a maximum that the card is capable of achieving
and maybe reduced by the restrictions of the X.25 network.
•
Dynamically managed adapter storage.
Depending on the interface you are using to attach your system to the X.25
network, select one of the following interface boards and cables:
•
V.24 Interface:
−
−
•
V.35 Interface:
−
−
•
6-Port V.36 (#2935)
6-Port V.35 Cable (#7106)
V.36 Interface:
−
−
•
8-Port RS-232-E/CCITT V.24 (#2929)
8-Port Cable (#7108 or 2939)
6-Port V.36 (#2935)
6-Port V.36 Cable (#2941)
X.21 Interface:
−
−
8-Port X.21 (#2938)
8-Port X.21 Cable (#2942)
The following figure illustrates the different configurations of the IBM ARTIC960
Adapter with each kind of EIB, device interface and cable:
Chapter 2. RISC System/6000 X.25 Support
31
Figure 17. IBM ARTIC960 Adapter Configurations
This adapter provides an increased number of WAN ports at T1/E1 speeds and
allows offloading of WAN protocols or applications onto the adapter. A powerful
processor and 4MB of memory provide a platform capable of offloading WAN
protocols or applications onto the adapter, freeing the host from these
computer-intensive tasks. This product is four to six times faster than previously
released ARTIC Portmaster family adapters and supports WAN link speeds of 2
Mbps. The adapter consists of a base adapter and one of the three
protocol-specific daughter cards (Application Interface Boards or AIBs). The
daughter cards offer:
•
8 port EIA 232 - (feature #2929, cable #2939)
•
6 port V.36 - (feature #2935, cable #2941)
•
8 port X.21 - (feature #2938, cable #2942)
With the new generation of adapters comes a new design in interface cables.
Whereas the Portmaster fanout box requires separate modem cables for modem
connection, the new ″octopus″ or fanout cable design combines the single
adapter connector with six or eight modem cables.
V.36 offers, essentially, a new generation of V.35 connection. One visible
difference is that V.36 uses a 37-pin D-shell connector while V.35 defines a
32
RS/0000 X.25 Cookbook
rectangular 34-pin connector. V.35 modem (or DSU/CSU) users may utilize the
new ARTIC960 V.36 adapter and the Portmaster′s V.35 fanout box and modem
cables. This V.35 configuration is supported for port speeds up to 64 Kbps. The
ARTIC960 EIA 232E/V.24 adapter users can also utilize the fanout box and cables
that were used in the 8-port Portmaster/A configuration.
ARTIC960 users must install the IBM ARTIC960 AIX Support Program for
RS/6000. This software is shipped with the adapter on diskette. This software
must be at V1.1.3 or later. Please ensure that the software on the diskette is
saved. To check that the software has been installed and is at the correct level
use the lslpp -l command. The output should be:
devices.artic960.rte
1.1.3.0
If the software is installed in the wrong order, you will need to follow the
recovery procedure included in the Hardware Installation section of the
AIXLink/X.25 1.1 for AIX Guide and Reference.
2.2.5 X.25 Device Driver and X.25 Ports
As the new X.25 LPP supports multiport adapters, more than one X.25 port can
be associated with a given adapter. The X.25 device driver handles the
communication between the ports and the communication adapter. Only one
device driver can be associated with each adapter. The X.25 ports are
associated with the individual communication ports supported by the adapter,
which can vary from one to eight.
Figure 18 on page 34 illustrates the relationship between driver instances:
apm0-n
An X.25 Portmaster device.
ampx0-n
An X.25 Co-Processor(/2) device.
ricio-n
An ARTIC960 device.
ddricio-n
IBM ARTIC960 Device Driver.
twd0-n
The device driver associated with the adapter. Each adapter supports
only ONE device driver.
sx25a0-n
A port associated with the device driver. Only one port is used for the
X.25 interface Co-Processor(/2) adapter and up to eight ports for the
Portmaster Adapter/A.
x25s0-n
An X.25 interface for COMIO emulation.
xs2
The X.25 TCP/IP interface configured on the X.25 port sx25a3.
Chapter 2. RISC System/6000 X.25 Support
33
Figure 18. Adapter, Device Driver, Port, Interface
2.2.6 X.25 Commands
The X.25 commands enable you to make use of the X.25 network without doing
any application programming yourself.
•
The X.25 commands are:
xroute
Manages COMIO X.25 routing table
xtalk
Communicates with other people, manages address lists for
outgoing calls
x25mon
Monitors the activity on an X.25 port at the frame or packet level
x25status Returns the state of X.25 ports
For more details on these tools see Chapter 4, “Tools” on page 73.
•
•
There are some AIX commands related to the setup and management of X.25
communications:
chsx25
Re-initializes the attributes of an X.25 port
lspvc
Lists the non-default PVC attributes for an X.25 port
lsx25
Lists the configuration of the X.25 support on the system
mkpvc
Creates or modifies a non-default PVC on an X.25 port
mksx25
Adds an X.25 port
rmsx25
Removes an X.25 port
chdev
Allows modification of the X.25 adapter attributes
lsattr
Shows the X.25 adapter and port attributes
Other X.25 commands related to high-level networking like TCP/IP, SNA, PAD
support include:
x25ip
34
RS/0000 X.25 Cookbook
Manages a translation table from IP addresses into X.25 network
user addresses (NUAs)
mksnaobj, chsnaobj, rmsnaobj, qrysnaobj
Creates, changes, removes and retrieves an SNA profile
xspad
Starts a terminal PAD session
x29d
Starts the x29 daemon
2.2.7 PAD Support
The new X.25 LPP supports X.3, X.28 and X.29 protocols. When the PAD support
is enabled, the X.29 daemon, x29d, supports all the configured X.25 ports and
services all remote terminals using the PAD. When the system is being used as
a terminal PAD, each terminal has its own X.3/X.28 session. To start an X.3/X.28
session, run the xspad command. The use of PAD is described in 5.1, “Using a
PAD” on page 91.
2.2.8 NPI Programming Interface
The Network Provider Interface (NPI) enables application access to the packet
layer of the protocol stack. It provides a connection-oriented programming
interface based on the UNIX International Standard NPI V2.0. A subset of the
standard has been implemented with enhancements to better suit it to an X.25
environment.
The NPI consists of a set of primitives defined as STREAMS messages that
provides access to the network layer services. For more details, see 6.3, “NPI
API” on page 123 and AIXLink/X.25 Version 1.1 for AIX: Guide and Reference
manual.
2.2.9 DLPI Programming Interface
The Data Link Provider Interface (DLPI) enables application access to the frame
or LAP-B layer of the protocol stack. To access the frame layer directly on a
port, the port′s configuration must be set to allow it. For more details, see 6.4,
“DLPI API” on page 128 and AIXLink/X.25 Version 1.1 for AIX: Guide and
Reference manual.
2.2.10 COMIO Emulation
COMIO Emulation provides application compatibility with applications developed
to the interface supported with AIX Version 3 X.25 support, (SNA, xtalk, etc.).
Applications developed for X.25 API provided with AIX Version 3 can use this
emulation without recompilation. For more details on the use of the COMIO API,
see 6.5, “COMIO API” on page 132 and AIXLink/X.25 Version 1.1 for AIX: Guide
and Reference manual.
2.2.11 SNMP
The AIX X.25 LPPs now support Simple Network Management Protocol.
2.2.11.1 What is SNMP?
The Simple Network Management Protocol (SNMP) is a protocol used by network
hosts to exchange information used in the management of networks. SNMP is
defined in several TCP/IP Requests for Comments (RFCs).
SNMP network management is based on the familiar client-server model that is
widely used in TCP/IP-based network applications. Each host that is to be
managed runs an agent, which is a server process that maintains the MIB
Chapter 2. RISC System/6000 X.25 Support
35
database for the host. Hosts involved in network management decisions may run
a process called a monitor. A monitor is a client application that generates
requests for MIB information and processes responses. In addition, a monitor
may send requests to agent servers to modify MIB information.
The Management Information Base (MIB) is a database containing the
information pertinent to network management. The database is conceptually
organized as a tree. The internal nodes of the tree represent subdivision by
organization or function. MIB variable values are stored in the leaves of this
tree.
2.2.11.2 X.25 and SNMP
The X.25 LPP SNMP support allows statistical data related to the X.25 interfaces
to be gathered and transferred to an SNMP agent for analysis. The items of data
gathered form a subset of the Management Information Base for X.25 specified
in RFCs 1381 and 1382:
RFC 1381 Defines MIB variables for X.25 frame layer
RFC 1382 Defines the MIB variables for X.25 packet layer
For the list of supported objects, see AIXLink/X.25 Version 1.1 for AIX: Guide and
Reference . For the use of the X.25 SNMP see 7.5, “Configuring SNMP” on
page 147.
2.2.12 SMP machines and X.25
AIXLink/X.25 V1.1.2 and higher will run on the SMP RS/6000 machines. The
AIXLink/X.25 LPP, however, is NOT SMP enabled. Nevertheless, the device
drivers for the X.25 cards run in what is termed as FUNNELED mode. This
means that the device drivers will run solely on the master processor and do not
take advantage of the other processors.
2.2.13 X.32
The X.32 protocol defines the way you can access a Packet Switched Public Data
Network (PSPDN) through a Public Switched Telephone Network (PSTN) or an
Integrated Services Digital Network (ISDN) or a Circuit Switched Public Data
Network (CSPDN).
The main advantages of using the X.32 protocol over dial-up lines are:
•
Better link efficiency due to less protocol overhead
•
The ability to run multiple sessions over a single dial-up link
•
Error control using LAPB
The X.32 recommendation provides four distinct methods for DTE identification.
These methods are:
•
Identification provided by the public switched network
•
Identification by means of a link layer Exchange Identification (XID)
procedure
•
Identification by means of a packet layer registration procedure
•
Identification by means of the NUI selection facility in call setup packets
The X.25 LPP provides X.32 support, allowing you the usage of XID procedure.
36
RS/0000 X.25 Cookbook
2.3 X.25 Power Management
2.3.1 General Power Management and X.25
The AIXLink/X.25 1.1 for AIX drivers have been updated to provide Power
Management Support. Power Management is a technique that enables hardware
and software to minimize system power consumption. This technique tends to be
emphasized only on low-end models and systems operating on battery. When
Power Management is enabled, the system enters a power-saving mode under a
number of conditions. Power Management state transitions include:
•
enable
•
standby
•
suspend
•
hibernation
•
shutdown
Each transitions implies further decreasing the power supplied to various system
components. Only suspend, hibernation and shutdown states have an impact on
X.25 connections. Drivers with NO Power Management awareness can prevent
Power Management capable systems from going into power-saving transitions.
The enhancement to AIXLink/X.25 V1.1.3 allows customers connected via X.25 to
packet switched data networks who want to utilize the suspend or hibernate
states to do so. This support is currently available to X.25 users running either
the Multiport 2 or X.25 Interface Co-Processor adapters in Power
Management-enabled ISA bus systems. When Power Management is configured
and enabled, the entire system goes into hibernate mode after a user-configured
period of inactivity from the keyboard. From an X.25 perspective, it is as though
the X.25 adapter cable has been unplugged from the NTU (modem or DSU/CSU).
All ports remain ″Available″ and applications continue to run although the
physical connection is broken.
Keyboard activity keeps systems in full-on state. X.25 link activity will neither
keep a system in full-on mode, nor reactivate it during hibernations. Therefore,
remote users will not be able to access AIX systems that are in either suspend
or hibernation mode. For this reason, Power Management is not recommended
for X.25 attached hosts running as unattended data servers.
2.3.2 Impact to Network Provider
As Power Management from a X.25 perspective is a loss of power to the
adapters, all network connections are lost. Since all signals are dropped at the
physical layer, there is no opportunity for the local DTE packet layer to send out
clear requests to the DCE. Also, the frame layer does not go through the usual
DISC/UA sequence prior to the link going down. Once power is restored, all X.25
connections which were physically connected will be restored. Two exceptions
are dial-up connections and those ports controlled directly by DLPI applications.
Restoring an X.25 connection refers to bringing up the physical, frame and
packet layers between the local DTE and DCE. Switched Virtual Circuits that
were active before the power loss will have been cleared. Permanent Virtual
Circuits will be reset. It is therefore up to the corresponding applications to
Chapter 2. RISC System/6000 X.25 Support
37
re-establish Switched Virtual Circuits and to properly resynchronize the
Permanent Virtual Circuits.
2.3.3 Impact to Local Applications
System shutdown impacts X.25 applications differently than suspend or
hibernation. Shutdown causes ALL user applications to be terminated. When
system shutdown is issued, no attempt is made to preserve the current user
state before power off and all X.25 user applications need to be restarted after
power-on. When suspend or hibernation states are entered, there is an attempt
to preserve as much of the current system state as possible. This is to make the
off-on cycle as transparent as possible to user applications. All user applications
remain active. In the case of X.25 applications there is a direct impact as the
network physical connections are lost. This makes the power-off and power-on
cycles not completely transparent.
The following briefly highlights how each of the interfaces behave during the
suspend or hibernation power-off/on cycles.
DLPI
It is up to the DLPI application to handle the indication when a
DL_DISCONNECT is received. The port is not active until a new
DL_CONNECT is received by the application.
TCP/IP
This interface is highly robust and transparent. In most cases, the
application does not even know that the underlying circuit was reset
or cleared.
NPI
When the suspend or hibernation states are entered a
N_DISCON_INDs is received by all SVCs and a N_RESET_INDs on all
configured and bound PVCs. The applictaion needs to be able to
handle these calls. All N_BIND_REQs are maintained as long as the
application does not issues an unbind. This implies that all PVCs
remain active, but SVCs need to be re-established.
COMIO Emulation In the case of a base X.25 API application running through
COMIO, all active SVCs are cleared and all PVCs are reset. Before
any of the sessions can be re-established, the application must
ensure that the sessions are properly aborted.
PAD
All active PAD connections are cleared when the suspend or
hibernation state is entered.
2.3.4 Power Management Limitation Warnings
The following is a list of things that it is NOT recommended to do while the
system is in a Power Management state.
•
Change the configuration during suspend/hibernation
Changing the configuration of devices or ports while the system is in
suspend/hibernation states can cause unpredictable results. It can cause
loss of data, filesystem corruption, a system crash or failure to resume from
the transition state.
•
Non-PM-aware device drivers
If a device driver is installed that is not Power Management aware, then the
suspend and hibernation state must NEVER be used as the results are
unpredictable.
•
38
RS/0000 X.25 Cookbook
Booting from CD-ROM or other media after hibernation
Accessing the rootvg from maintenance mode, such as a CD-ROM boot when
a valid hibernation image exists, can result in loss of data and filesystem
corruption.
•
Maintenance modes after hibernation
To avoid filesystem corruption and loss of data, only use maintenance modes
after a NORMAL system shutdown.
•
Network connections during suspend/hibernation
As network connections are disconnected during suspend/hibernation states,
it is recommended that these states are NOT used for machines running
following network interfaces.
X.25
TCP/IP
NFS
AFS
DCE
SNA
OSI
NetBIOS
•
Power Button Behavior
When Power Management is enabled, the power button is software
controlled. If there is a system problem, it should always be possible to turn
off the power by pressing the power button three times quickly. This
overrides whatever state transition was selected for for the power switch and
requires a full boot.
2.4 Hardware Requirements
AIXLink/X.25 Version 1.1 can be used on all systems that support AIX Version 4.x
with X.25 Interface Co-Processor/2 (FC 2960) or/and ARTIC Portmaster Adapter/A
(FC 7006/7008) or/and ARTIC960 Adapter (FC 2929, 2935, 2938) or X.25 Interface
Co-Processor (FC 6753). The X.25 Interface Co-Processor is available on models
supporting ISA I/O bus architecture only and requires AIX Version 4.x.
AIX X.25 Version 1.1 is supported on all systems that support AIX Version 3.2.5
for RISC System/6000 and the X.25 Interface Co-Processor/2 or/and ARTIC
Portmaster Adapter/A.
AIXLink/X25 Version 1.1 and AIX X.25 Version 1.1 require a minimum of 1 MB of
memory and 8 MB of free space in the /usr file system.
The maximum number of adapters per system is determined by the system
model.
Chapter 2. RISC System/6000 X.25 Support
39
Table 2. Throughput of the X.25 Adapters
Adapter
Software Support
Packets per second
Number Logical
Channels
X.25 Co-Processor/2
AIX V3 BOS
35
64 per adapter
X.25 Co-Processor/2
AIXLink LPP
100
512 per adapter
Portmaster/A
AIXLink LPP
200
512/port, 1024/adapter
ARTIC960
AIXLink V1.1.3
1,000
512/port, 1024/adapter
X.25 Co-Processor
AIXLink LPP
100
512 per adapter
Multiport Model II
AIXLink V1.1.3
200
512/port, 1024/adapter
MicroChannel bus:
ISA bus:
The above assumes 128-byte packets, measured at the packet layer API.
AIX V3 BOS assumes basic X.25 support which was included in the AIX V3 Base
Operating System.
2.5 Differences Between X.25 Support on AIX Versions
The following table shows the main characteristics and differences between X.25
support on AIX Version 3.2.x, AIXLink/X.25 versions 1.1 and 1.1.3. AIXL/X.25
Version 1.1.3 is supported on AIX Versions 4.1.4 and 4.2. For more information
about the differences between the X.25 support on AIX V3 and the X.25 LPP see
Appendix B, “Differences Between X.25 LPP and AIX V3 Base X.25 Support” on
page 239.
Table 3 (Page 1 of 2). Differences Between AIX Version 3.2.5, AIXLink Ver. 1.1 and AIXLink Ver. 1.1.3
Description
AIX Version 3.2.x
AIXLink/X.25 Version 1.1
AIXLink/X.25 Version 1.1.3
Applications:
TCP/IP
x
x
AIX Version 3 X.25 API
x
COMIO emulation
COMIO emulation
NPI and DLPI
-
x
x
SNA
x
x
x
PAD support
3rd Party
comes with the LPP
comes with the LPP
PAD printing
3rd Party
3rd p a r t y
comes with the LPP
-
x
x
xcomms
x
-
-
xroute
x
COMIO emulation
COMIO emulation
xmanage
x
-
-
x25status
-
-
x
xmonitor
x
-
-
x25mon
-
x
x
xtalk
x
COMIO emulation
COMIO emulation
Install separately
Installed with LPP
Installed with LPP except
ARTIC960
SNMP
IBM-Written commands:
Software Configuration:
Microcode Installation
separately
40
RS/0000 X.25 Cookbook
Table 3 (Page 2 of 2). Differences Between AIX Version 3.2.5, AIXLink Ver. 1.1 and AIXLink Ver. 1.1.3
Description
AIX Version 3.2.x
AIXLink/X.25 Version 1.1
AIXLink/X.25 Version 1.1.3
Hardware:
Adapter
IBM X.25 Co-Processor or Co-Processor/2
Max. Adapter per system
Max. Virtual circuits per
Adapter
4 / 8 •.•
-•
-•
64 •
512
512
Adapter
Portmaster Adapter
Max. Adapter per system
Max. Virtual circuits per
Adapter
-•,•
-•
-•
-•
1024 •
1024 •
Adapter
Multiport Model 2
Max. Adapter per system
-
-
-•
Max. Virtual circuits per
Adapter
-
-
1024 •
Adapter
ARTIC960 Adapter
Max. Adapter per system
-•
-•
-•
Max. Virtual circuits per
Adapter
-•
-
1024 •
X.25 Co-Processor, Co-Processor/2, Portmaster/A and Multiport Mod 2 - MODEM Cable / Maximum speeds:
X.21 (15-pin)
64 Kbps
64 Kbps
64 Kbps
V.24 (25-pin)
19.2 Kbps
19.2 Kbps
19.2 Kbps
V.35 (34-pin)
64 Kbps •
64 Kbps •
64 Kbps •
X.25 ARTIC960 - MODEM Cable / Maximum speeds:
X.21 (15-pin)
-
-
2 Mbps
V.24 (25-pin)
-
-
19.2 Kbps
V.35 (34-pin)
-
-
64 Kbps •
V.36 (37-pin)
-
-
2Mbps.
Note:
•Up to eight adapters are supported on systems with dual Micro Channel. Each Micro Channel supports 4 adapters.
•The number of adapters is limited to the number supported in each RISC System/6000.
•The ARTIC Portmaster adapter was not supported for X.25 communications on AIX V3.x without the X.25 LPP.
•1024 is the recommended maximum number of VCs. 512 VCs are supported for each port.
•The V.35 specification actually defines 56 Kbps as the maximum line speed. In the case of the RISC System/6000, we
exceed the specification.
The X.25 Co-Processor is supported on systems with ISA bus only.
2.5.1 Adapter Speeds
Although the IBM adapters support line speeds up to 2Mbps, it is unlikely
running at these speeds will be successful unless connected to superior
networks. A high-quality line and external clocking are required.
Chapter 2. RISC System/6000 X.25 Support
41
42
RS/0000 X.25 Cookbook
Chapter 3. X.25 LPP Installation and Setup
In this chapter you will find a step-by-step description of the installation process
for supported adapters, the modem setup and the minimal customization of the
X.25 support for switched virtual circuits.
Two scenarios will be described: the first is a real-life configuration with two
RISC System/6000s connected through a public packet switching data network,
and the second is a test configuration with two systems connected back-to-back
through a synchronous modem eliminator.
3.1 Overview and Fast Path
This section overviews the hardware and software configuration of an X.25
connection. This will be an overview of two connection scenarios. Detailed steps
will be covered in following sections of this chapter.
3.1.1 Scenario 1: Two RISC System/6000s Connected to a PSDN
Figure 19. RISC System/6000s Connected to the TYMNET PSDN
 Copyright IBM Corp. 1996
43
Setup for the Connection to a PSDN
•
Hardware preparation:
1. Install the X.25 adapter.
2. For ARTIC960 only, install the ARTIC960 AIX Support Program for
RISC/6000 for AIX Version 4.
3. Connect the system to the NTU (modem or DSU/CSU).
•
Software configuration:
1. Install the X.25 LPP.
2. Configure the X.25 device driver.
3. Configure the X.25 port.
4. With smit x25str_mp_csp_g_sel, configure the NUA, the number of
logical channels and the virtual circuit types to match your PSDN
network subscription.
Virtual circuits can now be defined during X.25 port configuration.
Note: ARTIC960 is supported only by AIXLink/X.25 Ver. 1.1.3 on AIX Ver. 4.
If you install the ARTIC960 adapter after AIXLinkX.25, you may encounter
a method error. If this occurs, run the
/usr/lpp/sx25/inst_root/sx25.ret.config script.
3.1.2 Scenario 2: Two RISC System/6000s Connected by a Modem Eliminator
Figure 20. RISC System/6000s Connected Back-to-Back
44
RS/0000 X.25 Cookbook
Setup for Two RISC System/6000s Back-to-Back
•
Hardware preparation:
1. Install the X.25 adapter in any appropriate slot.
2. Connect the system to the synchronous modem eliminator.
Note: Synchronous modems with 4-wire transmit/receive
connections can be used if a modem eliminator is not
available.
•
Software configuration:
1. Install X.25 LPP.
2. Configure X.25 device driver.
3. Configure X.25 port.
4. Configure one system as DTE and the other as DCE or set the Allow
automatic DTE/DCE detection parameter to yes-automatic. This is the
default setting.
5. With smit x25str_mp_csp_g_sel, configure the number of logical
channels and virtual circuit types to match your PSDN network
subscription.
Virtual circuits can now be defined during X.25 port configuration.
3.2 Hardware Installation
This section provides descriptions of the installation and configuration of the
supported IBM X.25 adapters and related cables.
3.2.1 Installing the Adapter
The X.25 Co-Processor/2, ARTIC Portmaster Adapter/A or ARTIC960 adapter may
be installed in any available Micro Channel slot. The X.25 Co-Processor or
Multiport Model 2 adapter may be installed in any available ISA slot.
Note: It is good practice to execute the diag -a command before installing any
adapters.
3.2.1.1 Installation of the X.25 Co-Processor(/2)
The X.25 Interface Co-Processor/2 may be installed in any of the available Micro
Channel slots in the RISC System/6000.
The X.25 Interface Co-Processor may be installed in any of the available ISA
slots in the RISC System/6000.
See 3.6, “Configuring ISA X.25 Adapters” on page 65 for information on ISA
adapter interrupt switches.
Use SMIT to configure the adapter.
Once installed, check the adapter with:
lsdev -C -H -t articmpx
If you get an output like:
Chapter 3. X.25 LPP Installation and Setup
45
name status
location description
ampx0 Available 00-05
X.25 Co-Processor/2 Adapter
Then the adapter is installed correctly.
But if you get an output like:
name status
ampx1 Defined
location description
00-03
X.25 Co-Processor/2 or Multiport/2 Adapter
then the adapter was once installed in the machine, but now it is removed or
must be configured using SMIT.
Note: The X.25 Co-Processor for ISA bus interrupt level is set using switches.
Refer to the adapter and system unit documentation to determine a
proper interrupt level.
3.2.1.2 Installation of the Portmaster or Multiport 2 Adapter
The portmaster Adapter may be installed in any of the available Micro Channel
slots in the RISC System/6000.
The Multiport Model 2 adapter may be installed in any ISA slot.
Use SMIT to configure the adapter. Once installed, check the adapter with:
# lsdev -C -H -t portmaster
If you get an output like:
name status
location description
apm0 Available 00-01
6-Port Portmaster Adapter/A V.35
apm1 Available 00-02
6-Port Multiport Model 2 V.35
then the adapter is installed correctly.
But if you get an output like:
name status
apm0 Defined
location description
00-01
6-Port Portmaster Adapter/A V.35
then the adapter was once installed in the machine, but now it is removed or
must be configured using SMIT.
3.2.1.3 Installation of the ARTIC960 Adapter
You must install the ARTIC960 AIX Support Program for RISC/6000 sofware for
AIX Version 4 to use the ARTIC960 Adapter. The support program is shipped on
a diskette packaged with the adapter. The support program should be installed
before installing the adapter. If you install the support program after the adapter
is installed, run the /usr/lpp/sx25/inst_root/sx25.rte.config script.
The ARTIC960 Adapter may be installed in any of the available Micro Channel
slots in the RISC System/6000.
Use SMIT to configure the adapter. Once installed, check the adapter with:
# lsdev -C | grep 960
If you get an output like:
46
RS/0000 X.25 Cookbook
name
status
location
ricio0
Available 00-05
ddricio0 Available 00-05-00
description
IBM ARTIC960 Adapter
IBM ARTIC960 Device Driver
then the adapter is installed correctly.
But if you get an output like:
name
ricio0
status location
Defined 00-05-00
description
IBM ARTIC960 Adapter
then the adapter was once installed in the machine, but now it is removed or
must be configured using SMIT.
3.2.2 Physical Connections to the Network
The IBM X.25 adapters support three different line driver circuits to
accommodate three different types of connections: X.21, X.21bis/V.24 and
X.21bis/V.35. These three circuits are all connected to the X.25 Co-processor′ s
37-pin connector or to the Portmaster Adapter′s Electrical Interface Board (fanout
connector).
3.2.2.1 X.25 Co-Processor(/2) V.24, V.35 and X.21 Cables
Both IBM single port X.25 Co-Processors use the same cables.
Table 26 on page 248 shows which pins are attributed to which circuit. Using
two cable identification pins, ID0 and ID1, the adapter can determine which cable
is attached and activate the appropriate line driver.
X.21 Connection: The CCITT-defined X.21 attachment as the digital interface
originally planned for an X.25 public network. In practice, very few countries are
offering this capability yet. The X.21 cable is terminated by a 15-pin D-shell
connector and is described in C.1.3.1, “X.21 Interface Cable” on page 253. The
IBM references for the X.21 cable are:
#2965 PN 07F3151 for the 3-meter X.21 cable
#2976 PN 53F3926 for the 6-meter X.21 cable
When necessary, use the description given in C.1.3.1, “X.21 Interface Cable” on
page 253 to make an X.21 cable.
.
X.21bis Connections: V.24 and V.35: As an interim measure before the
generalization of X.21, the CCITT has issued the X.21 bis recommendation
defining the use of the popular V-series modems for X.25 networks. Normal
synchronous V.24 modems can be used for speeds up to 19200 bps or V.35
modems for greater speeds. Modem pin assignments and cable descriptions
are given in C.1.2.2, “V.24/X.21bis Pin Assignment” on page 251 and in C.1.2.3,
“V.35/X.21bis Pin Assignment” on page 252.
The IBM feature and part numbers for the V.24 and V.35 cables are:
#2966 PN 07F3161 for the 3-meter V.24 cable
#2977 PN 53F3927 for the 6-meter V.24 cable
#2978 PN 53F3928 for the 6-meter V.35 cable
#2967 PN 07F3171 for the 3-meter V.35 cable
Chapter 3. X.25 LPP Installation and Setup
47
Note: In France, a V.35 pin adapter, Feature Code #2703, is required with
the V.35 cables
If necessary, use the description given in C.1.3.2, “X.21bis/V.24 Interface Cable”
on page 254 and C.1.3.3, “X.21bis/V.35 Interface Cable” on page 255 to make a
cable.
3.2.2.2 Portmaster Adapter V.24, V.35 and X.21 Cables
C.2, “IBM Portmaster Adapter/2 and Multiport Model 2” on page 257 shows
which pins are assigned to which circuit.
As we saw in the previous chapter, the Interface cables for the three interfaces
are:
V.24 interface: FC 7108 or FC 2939 (See Figure 17 on page 32.)
V.35 interface: FC 7106
X.21 interface: FC 7110
IBM cables available for NTU(modem) connection to these are:
V.24 interface: FC 2706 (P/N 71F0165)
V.35 interface: FC 7107 (P/N 11H4958)
X.21 interface: FC 7111 (P/N 11H4957)
If necessary, use the description given in Appendix C, “X.25 Cables and
Connectors” on page 247 to make the cables yourself.
3.2.2.3 Multiport Model 2 V.24, V.35 and X.21 Cables
C.2, “IBM Portmaster Adapter/2 and Multiport Model 2” on page 257 shows
which pins are assigned to which circuit.
As we saw in the previous chapter, the Interface cables for the three interfaces
are:
V.24 interface: PS/2 FC 6366
V.35 interface: PS/2 FC 1211
X.21 interface: PS/2 FC 2028
IBM cables available for NTU(modem) connection to these are:
V.24 interface: FC 2706 (P/N 71F0165)
V.35 interface: FC 7107 (P/N 11H4958)
X.21 interface: FC 7111 (P/N 11H4957)
If necessary, use the description given in Appendix C, “X.25 Cables and
Connectors” on page 247 to make the cables yourself.
3.2.2.4 ARTIC960 V.24, V.35, V.36 and X.21 Cables
C.2, “IBM Portmaster Adapter/2 and Multiport Model 2” on page 257 shows
which pins are assigned to which circuit.
As we saw in the previous chapter, the Interface cables for the four interfaces
are:
V.24 interface: FC 2939
48
RS/0000 X.25 Cookbook
V.35 interface: FC 7106
V.36 interface: FC 2941
X.21 interface: FC 2942
IBM cables available for NTU(modem) connection to these are:
V.35 interface: FC not available yet (P/N 11H4958)
If necessary, use the description given in Appendix C, “X.25 Cables and
Connectors” on page 247 to make the cables yourself.
3.2.3 X.25 Connection Test Scenarios
To test the X.25 connection between two RISC System/6000s, the best solution is
to have two RISC System/6000s connected to a public X.25 packet-switched data
network. If you don′t have these resources, you can still perform some tests
with an X.25 network simulator or with two RISC System/6000s connected
back-to-back. It is even possible, in some cases, to use only one RISC
System/6000. In the following paragraphs we will describe the feasible test
configurations.
3.2.3.1 Two RISC System/6000s Connected to a Real X.25 Network
Each system must have a subscription to a PSDN. Each RISC System/6000 is
connected to the network through a modem, DSU/CSU, provided by the network
supplier called an NTU (Network Terminating Unit) whose settings you are not
allowed to alter. Each RISC System/6000 is configured as a DTE and has its own
NUA (Network User Address) assigned by the network provider. Figure 21 shows
such a configuration.
Figure 21. Two RISC System/6000s Connected to an X.25 Network
3.2.3.2 Single RISC System/6000 Connected to a Real X.25
Network
Most applications will allow you to call yourself through the X.25 network. We
have tested this scenario with xtalk (see 4.1, “The xtalk Tool” on page 73). You
cannot use this configuration to test TCP/IP or SNA over an X.25 network
because those protocols determine that the host you are calling is the local host
and that it doesn′t need to go through the X.25 network to reach it.
Chapter 3. X.25 LPP Installation and Setup
49
Figure 22. One RISC System/6000 Connected to an X.25 Network
Warning: Some X.25 networks may not allow this call loopback capability.
3.2.3.3 Two RISC System/6000s Connected to an X.25 Network
Simulator
An X.25 network simulator is a commercially available device simulating an X.25
network to which X.25 DTEs can be attached, either remotely through a pair of
modems or locally with a modem eliminator. The X.25 functions that can be
tested depend on the capabilities of the simulator.
Figure 23. Two RISC System/6000s Connected to an X.25 Network Simulator
3.2.3.4 Two RISC System/6000s Connected Back-to-Back
In this point-to-point configuration, the two systems may be side-by-side,
connected by a synchronous modem eliminator, or one may be remotely
connected by a four-wire line through a pair of synchronous modems.
This configuration allows you to test communications with PVCs or SVCs but
doesn′t have the same customizing problems you will experience on a real
50
RS/0000 X.25 Cookbook
network. We don′t encourage using this configuration in production
environments; this is just for test purposes.
Figure 24. Two RISC System/6000s Connected Back-to-Back
3.2.3.5 One RISC System/6000 and No X.25 Network
Yes, it works. ... You can you can use two ports belonging to the same
Portmaster Adapter, or you can use two adapters. (Each adapter can be a
Portmaster Adapter or an X.25 Co-Processor Adapter.) One port must be
configured as a DTE and the other as a DCE, or you must define the Allow
automatic DTE/DCE detection parameter as yes-automatic. This configuration has
the same limitations as the previous one. In addition, it is not suitable to test
TCP/IP or SNA for the reasons given in the case of one machine connected to a
network.
Figure 25. One RISC System/6000 with Two X.25 Co-Processors
Chapter 3. X.25 LPP Installation and Setup
51
3.2.4 Modem Considerations
If you are connected to a public X.25 network, you will probably have no
problems with the modems because they are provided and configured by the
network supplier. You are not allowed to change the configuration.
In other cases, you will have to select and set up the modems (or modem
eliminator). You may, for example, choose a V.24 synchronous full-duplex
modem for leased line, a limited distance synchronous modem or a V.24
synchronous modem eliminator. You can choose any speed between 1200 and
19200 bps, the faster, the better. There will be no need to specify this speed in
the RISC System/6000 customization because the X.25 adapters will use the
clock signal generated by the modem.
If your modem can be customized, verify the following settings:
1. The transmit (114) and receive (115) clock signals must be provided by the
mo d e m
2. The DSR signal may be either forced on (108-1) or controlled by the DTR
(108-2)
3. The CTS signal (106) may be either forced on or controlled by the RTS
4. The RTS to CTS delay can be anything
The diagnosis of modem-related problems will be easier if you can get a V.24
breakout box to monitor the status of each V.24 line.
3.3 Software Customization
This section is a step-by-step description of the installation and customization of
the X.25 LPP for both AIX 4.1.4 and AIX 4.2.
3.3.1 Installing the X.25 LPP Software
The first step on the software customization process is the X.25 LPP installation.
To check if the X.25 is already installed, try:
# lslpp -h “sx25*”
If your system is running AIX Version 3.2.5, you get:
Name
------------------Fix Id Release
Status
Action
Date
Time
User Nam
--------- ---------- -------- ------- --------- --------- ------------Path: /usr/lib/objrepos
sx25.x25.obj
01.01.0000.0000 COMPLETE APPLY
09/20/94 21:03:35 root
Or if your system is running AIX Version 4.x, you get the following output from
lslpp -l sx25*
Fileset
Level State
Description
---------------------------------------------------------------------------Path: /usr/lib/objrepos
sx25.adt.comio
1.1.3.0 COMMITTED AIXlink/X.25 Application
Development Toolkit - COMIO
Support
52
RS/0000 X.25 Cookbook
sx25.adt.npi
sx25.adt.rte
sx25.comio
sx25.info.en_US.usr_gd
sx25.msg.De_DE.rte
sx25.msg.En_US.rte
sx25.msg.Es_ES.rte
sx25.msg.Fr_FR.rte
sx25.msg.It_IT.rte
sx25.msg.Ja_JP.rte
sx25.msg.Nl_BE.rte
sx25.msg.de_DE.rte
sx25.msg.en_US.rte
sx25.msg.es_ES.rte
sx25.msg.fr_FR.rte
sx25.msg.it_IT.rte
sx25.msg.ja_JP.rte
sx25.msg.nl_BE.rte
sx25.msg.zh_TW.rte
sx25.npi
sx25.pad
sx25.rte
sx25.server
sx25.tcpip
Path: /etc/objrepos
sx25.comio
sx25.rte
sx25.tcpip
1.1.3.0 COMMITTED AIXlink/X.25 Application
Development Toolkit - NPI/DLPI
1.1.3.0 COMMITTED AIXlink/X.25 Application
Development Toolkit - Runtime
Env.
1.1.3.0 COMMITTED AIXlink/X.25 COMIO
Compatibility Support and
Applications
4.2.0.0 COMMITTED X.25 User Guides - U.S.
English
1.1.1.0 COMMITTED AIXlink/X.25 Messages - German
IBM-850
1.1.1.0 COMMITTED AIXlink/X.25 Messages - U.S.
English IBM-850
1.1.1.0 COMMITTED AIXlink/X.25 Messages Spanish IBM-850
1.1.1.0 COMMITTED AIXlink/X.25 Messages - French
IBM-850
1.1.1.0 COMMITTED AIXlink/X.25 Messages Italian IBM-850
1.1.1.0 COMMITTED AIXlink/X.25 Messages Japanese
1.1.1.0 COMMITTED AIXlink/X.25 Messages Belgian Dutch IBM-850
1.1.1.0 COMMITTED AIXlink/X.25 Messages - German
1.1.1.0 COMMITTED AIXlink/X.25 Messages - U.S.
English
1.1.1.0 COMMITTED AIXlink/X.25 Messages Spanish
1.1.1.0 COMMITTED AIXlink/X.25 Messages - French
1.1.1.0 COMMITTED AIXlink/X.25 Messages Italian
1.1.1.0 COMMITTED AIXlink/X.25 Messages Japanese IBM-eucJP
1.1.1.0 COMMITTED AIXlink/X.25 Messages Belgian Dutch
1.1.1.0 COMMITTED AIXlink/X.25 Messages Traditional Chinese
1.1.3.0 COMMITTED AIXlink/X.25 NPI and DLPI
Support
1.1.3.0 COMMITTED AIXlink/X.25 Triple-X Packet
Assembler/Disassembler (PAD)
1.1.3.0 COMMITTED AIXlink/X.25 Runtime
Environment
1.1.3.0 COMMITTED AIXlink/X.25 Server Support
1.1.3.0 COMMITTED AIXlink/X.25 TCP/IP Support
1.1.3.0 COMMITTED AIXlink/X.25 COMIO
Compatibility Support and
Applications
1.1.3.0 COMMITTED AIXlink/X.25 Runtime
Environment
1.1.3.0 COMMITTED AIXlink/X.25 TCP/IP Support
The X.25 LPP has already been installed in your system.
Chapter 3. X.25 LPP Installation and Setup
53
3.3.1.1
AIX V4.x X.25 LPP Installation
To retain a copy of the SMIT menus and commands used during X.25
customization, delete or rename smit.log and capture the image of each SMIT
menu. This can be retained for future reference.
Note: After successfully customizing, save your X.25 environment using the
/usr/lpp/sx25/bin/backupx25 command.
Use the following SMIT sequence to install the X.25 LPP on AIX Version 4.1:
Software Installation and Maintenance
→
Install and Update Software
→
Install/Update Selectable Software (Custom Install)
→
Install Software Products at Latest Level
→
Install New Software Products at Latest Level
Or use the fastpath:
smit install_latest
Select your input device, and then you′ll get:
Install New Software Products at Latest Level
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* INPUT device / directory for software
* SOFTWARE to install
PREVIEW only? (install operation will NOT occur)
COMMIT software updates?
SAVE replaced files?
ALTERNATE save directory
AUTOMATICALLY install requisite software?
EXTEND file systems if space needed?
OVERWRITE same or newer versions?
VERIFY install and check file sizes?
Include corresponding LANGUAGE filesets?
DETAILED output?
[Entry Fields]
/dev/rmt0.1
[1.1.3.0 sx25
no
yes
no
[]
yes
yes
no
no
yes
no
Use F4 or key in the SOFTWARE to install.
The software is:
1.1.3.0 sx25 ALL sx25 1.1.3.0.all
Or you can press F4 and then select this option. Use the following SMIT
sequence to install the X.25 LPP on AIX Version 4.
Software Installation and Maintenance
→
Install and Update Software
→
Install and Update from LATEST Available Software
Select your input device, and then you will get:
54
RS/0000 X.25 Cookbook
> +
+
+
+
+
+
+
+
+
+
Install and Update from LATEST Available Software
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* INPUT device / directory for software
* SOFTWARE to install
PREVIEW only? (install operation will NOT occur)
COMMIT software updates?
SAVE replaced files?
AUTOMATICALLY install requisite software?
EXTEND file systems if space needed?
OVERWRITE same or newer versions?
VERIFY install and check file sizes?
Include corresponding LANGUAGE filesets?
DETAILED output?
[Entry Fields]
/dev/rmt0.1
[]
no
yes
no
yes
yes
no
no
yes
no
+
+
+
+
+
+
+
Choose SOFTWARE to install by pressing F4.
3.3.1.2 X.25 Virtual License Information
If the AIXLink/X.25 product is installed on a system running AIX Version 4.1, the
X.25 LPP requires the virtual circuit license information. This information does
not need to be supplied if the AIXLink/X.25 product is installed on a system
running AIX Version 3.2.5 or if the AIXLink/X.25 entry level capacity product is
installed.
To enter the X.25 license level, use the SMIT sequence:
Software License Management
→
Manage X.25 Server License Database
From the Change/Show Number of X.25 Virtual Circuits menu, select one of the
following license levels depending on the X.25 virtual circuit license ordered:
Entry (>5)
Basic (<17)
Extended (<65)
Advanced (<257)
Unrestricted
3.3.2 Configuring the X.25 Device Driver
After installing the X.25 LPP, you must configure the X.25 LPP device driver. The
following steps are the same for AIX 4.1.4 and 4.2. From the SMIT main menu,
select the following:
Devices
→
Communication
→
(choose your adapter type)
→
Adapter
→
Manage Device Drivers for (adapter)
→
Manage X.25 LPP Device Driver
→
Add a Device Driver
Or you can use the appropriate fast path as follows:
Chapter 3. X.25 LPP Installation and Setup
55
Adapter Type
Fastpath
----------------------------------------------------------------X.25 Co-Processor/2 or Multiport/2 Adapter cx25str_dd
Portmaster Adapter/A
x25str_dd
IBM ARTIC960 Adapter
ax25str_dd
X.25 Co-Processor/1 Adapter
cx25str_dd
Multiport Model 2 Adapter
x25str_isa_dd
Select the X.25 adapter:
Parent Adapter
Move cursor to desired item and press Enter.
ampx0 Available 00-05 X.25 Co-Processor/2 Adapter
apm0 Available 00-01 8-Port Portmaster Adapter/A RS-232
apm0 Available 00-01 6-Port Portmaster Adapter/A X.21
apm0 Available 00-01 6-Port Portmaster Adapter/A V.35
ricio0 Available 00-07 IBM ARTIC960 Adapter
ampx0 Available 01-02 X.25 Co-Processor/1 Adapter
apm0 Available 01-02 6-Port Multiport Model 2 Adapter (V.35)
apm0 Available 01-02 8-Port Multiport Model 2 Adapter (RS-232)
apm0 Available 01-02 6-Port Multiport Model 2 Adapter/A (X.21)
F1=Help
F8=Image
/=Find
F2=Refresh
F10=Exit
n=Find Next
F3=Cancel
Enter=Do
3.3.3 Configuring an X.25 LPP Port
Once the device driver is available, you must configure an X.25 LPP port. You
must know the Network User Address and Network Identifier of your network
subscription. To add a port, select the following starting from the SMIT main
menu:
Devices
→
Communication
→
(select one of the following adapter)
X.25 Co-Processor/2 or Multiport/2 Adapter
Portmaster Adapter/A
IBM ARTIC960 Adapter
X.25 Co-Processor/1 Adapter
Multiport Model 2 Adapter
→
Adapter
→
Manage Device Drivers for (your adapter type)
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
Or use the SMIT fastpath:
Adapter Type
Fastpath
----------------------------------------------------------------X.25 Co-Processor/2 or Multiport/2 Adapter
cx25str_mp
Portmaster Adapter/A
px25str_mp
IBM ARTIC960 Adapter
ax25str_mp
X.25 Co-Processor/1 Adapter
cx25str_mp
Multiport Model 2 Adapter
px25str_mp
Now, select the next menu:
56
RS/0000 X.25 Cookbook
→Add Port
Select the Adapter Driver that contains the port you want to configure, and fill in
your network subscription data:
Add an X.25 Port
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Parent adapter driver
* PORT number
* Local network user address (NUA)
* Network identifier
Country prefix
PVC - lowest logical channel number
PVC - number of logical channels
Incoming SVC - lowest logical channel number
Incoming SVC - number of logical channels
Two-way SVC - lowest logical channel number
Two-way SVC - number of logical channels
Outgoing SVC - lowest logical channel number
Outgoing SVC - number of logical channels
[Entry Fields]
twd0
[0]
[3106010761]
[other public]
[]
[0]
[0]
[0]
[0]
[1]
[1]
[0]
[0]
+
#
#
#
+
+
+
+
+
+
+
+
Note: The above menu is the same for each of the adapters you choose.
The AIX-generated command is:
mksx25 -c port -s star -t stx25 -p ′ twd0′ -w ′ 0 ′ -a local_nua=′3106010761′ -a
network_id=′ 5 ′ -a by_vc_start=′ 1 ′ -a bi_vc_num=′ 1 ′
The contents of these fields are as follows:
•
PORT number:
−
If you are using any of the following adapters, the port number must be
zero.
- X.25 Co-Processor/2
- Co-Processor/1 Adapter
−
If you are using any of the following adapters, select the number of the
port you are configuring.
- Portmaster Adapter/A
- IBM ARTIC960 Adapter
- Multiport Model 2 Adapter
•
•
Network User Address (NUA):
−
If you are connected to a public network, your subscription information
will contain your network user address, (NUA). Use the international
format with the country code in the first three positions.
−
If you are connected to a private network, your network administrator will
provide you with an address.
Network Identifier:
This is a multiple-choice question. Press F4 and the following list will be
displayed:
Chapter 3. X.25 LPP Installation and Setup
57
Datex-P
Datapac
Telenet
DDN
other public
other private
Extended PSS-1
Transpac
−
If your network name is listed above, select it.
−
If it is not listed and you are connected to a public network that allocates
NUAs in accordance with the CCITT X.121 standard, select other public.
In this case, the country code will be sufficient to identify the network and
select the appropriate parameters.
−
If you are connected to a test environment, or to any other private
network where the NUAs do not have a country code, use other private.
•
Local Network User Address: Must match you network subscription.
•
Country prefix: Used to set default country code in NUA.
3.3.4 Updating the Number of Virtual Channels
This step modifies the definitions done as part of port configuration.
In your X.25 subscription, look for the number of logical channels you have
subscribed to and for the number of the first channel. Then use SMIT to modify
these values on the RISC System/6000:
Devices
→
Communication
→
(your adapter type)
→
Adapter
→
Manage Device Drivers for (your adapter type)
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Change / Show Characteristics of Port
→
Change / Show General Parameters
Or use the fastpath: smit x25str_mp_csp_g_sel
Since our network subscription was for 64 bidirectional SVCs starting at logical
channel 1, the setting is:
58
RS/0000 X.25 Cookbook
Change / Show X.25 General Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
Port name
Local network user address (NUA)
Calling address in call request/accept packet
Enable DLPI interface ONLY
PVC - lowest logical channel number
PVC - Number of logical channels
Incoming SVC - lowest logical channel number
Incoming SVC - number of logical channels
Two-way SVC - lowest logical channel number
Two-way SVC - number of logical channels
Outgoing SVC - lowest logical channel number
Outgoing SVC - number of logical channels
[Entry Fields]
sx25a0
[3106010760]
[allow]
[no]
[0]
[0]
[0]
[0]
[1]
[64]
[0]
[0]
#
+
+
+#
+#
+#
+#
+#
+#
+#
+#
X.32 Configuration
[MORE...14]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
SMIT checks for VC hierarchy and overlapping SVC and PVC ranges, see 1.6.5,
“Types of Virtual Circuits” on page 15. For instance, if you try to configure two
PVCs with lowest logical channel number one and 62 SVCs with lowest logical
channel 2, you′ll get this error:
COMMAND STATUS
Command: failed
stdout: no
stderr: yes
Before command completion, additional instructions may appear below.
Method error (/etc/methods/chgsx25):
0514-018 The values specified for the following attributes
are not valid:
chgsx25: Invalid two-way SVC lowest channel number
bi_vc_start
Lowest logical channel number for a two-way SVC
F1=Help
F8=Image
F2=Refresh
F9=Shell
F3=Cancel
F10=Exit
F6=Command
Chapter 3. X.25 LPP Installation and Setup
59
Notes:
•
A maximum of 512 virtual circuits is supported per line.
•
The information concerning the number of virtual circuits must be correct;
any larger or smaller number will cause problems.
•
We assume that you have subscribed to bidirectional switched virtual
circuits, but other possibilities are incoming SVCs, outgoing SVCs and PVCs.
An incoming SVC can only receive calls, not make them. An outgoing SVC
can only be used to make calls, not to receive them. Once the sessions are
established, communications are two-way on the virtual circuit.
3.3.5 Modifying Other Parameters
Considering the number of parameters involved, the customization of a RISC
System/6000 connected to an X.25 network may seem difficult. Actually, only a
few parameters are essential, and they have CCITT-defined default values. In
addition, the configuration process uses the country code of the NUA and the
network type information entered at the beginning of the configuration to set
default values that are unique to a country network.
The following parameter default values are CCITT standards that can be changed
only as a subscription option. Check your subscription to see if any of the
following parameters is mentioned with non-standard values:
Table 4. Standard Value of Important Parameters
Parameter
Default
SMIT Fast Path
Frame window size
7
x25str_mp_csp_f_sel
Frame modulo
8
x25str_mp_csp_f_sel
Packet modulo
8
x25str_mp_csp_p_sel
CCITT support
1988
x25str_mp_csp_p_sel
Default receive packet size
128
x25str_mp_csp_p_sel
Default transmit packet size
128
x25str_mp_csp_p_sel
Default receive packet window
3
x25str_mp_csp_p_sel
Default transmit packet window
3
x25str_mp_csp_p_sel
Default receive throughput class
64000
x25str_mp_csp_p_sel
Default transmit throughput class
64000
x25str_mp_csp_p_sel
Notes:
•
None of these parameters can be defined arbitrarily by the user. You must
use actual values defined on your network. Using the packet level
negotiation facilities, you will be able to modify these values for each virtual
call; you cannot do this by changing the defaults.
•
If a default parameter, the packet size for example, is associated with
parameters giving its maximum and/or minimum value, you must take care
to modify them so that the default value falls between the maximum and the
minimum.
In our case, we requested a non-standard default value of 1024 octets for the
packet size (rather unusual). From the SMIT menu, we selected:
60
RS/0000 X.25 Cookbook
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/2
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Change / Show Characteristics of Port
→
Change / Show Packet Parameters
Or use the fastpath: smit x25str_mp_csp_p_sel
Change / Show X.25 Packet Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
Port name
CCITT support
Packet modulo
Type of line
Packet layer DTE/DCE line alteration policy
Disconnect on inactivity
Registration
A-bit
Network intermediate data unit (nidu) size
Default Attributes for SVCs
**********
Default receive packet size
Default transmit packet size
[MORE...37]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
[Entry Fields]
sx25a0
[1984]
[8]
[DTE]
[per OSI 8208 procedure]
[no]
[no]
[off]
[200]
+#
+#
+
+
+
+
+
+#
[1024]
[1024]
+#
+#
F4=List
F8=Image
The maximum packet size would also have to be increased from the default of
256 to avoid errors in this example.
You have now set up all necessary X.25 parameters for a test environment. To
have a convenient list of the X.25 parameters on your system that will help you if
any problem occurs during the connection tests, type:
# lsattr -E -H -l sx25a0 | grep -v pvc
The output includes:
..
.
network_id
local_nua
in_svc
num_in_svcs
in_out_svc
num_in_out_svc
5
3106010760
0
0
1
20
Network identifier
Network User Address
Lowest logical channel number for an incoming SVC
Number of logical channels for incoming SVCs
Lowest logical channel number for an two-way SVC
Number of logical channels for two-way SVCs
.
Chapter 3. X.25 LPP Installation and Setup
61
..
The grep filter is used to eliminate the PVC parameters from the list by
suppressing all the lines containing the string “pvc.”
3.3.6 Customization for the Back-to-Back Scenario
Figure 26. Two RISC System/6000s Connected Back-to-Back
If you are connecting two systems back-to-back, you can benefit from the
automatic DTE/DCE detection feature. If this feature has been disabled, you must
define one system as DTE and the other as DCE.
Because we will use switched virtual circuits (SVCs), we will have to assign X.25
addresses (NUAs) to our two hosts, fili and kili. NUAs should be assigned by a
network provider.
In this instance, you are providing your network.
Note: Since this is a TEST environment, NUAs may be arbitrarily selected. In
any production environment, NUAs must be obtained from the network
provider.
The DNIC (first four digits of the NUA) of TYMNET being 3106, we have assigned
the following NUA values for fili and kili:
Table 5. NUAs Used for Back-to-Back Scenario
Machine Name
NUA
kili
3106000001
fili
3106000002
3.3.6.1 X.25 Adapter Initialization
Once the hardware has been prepared, we can continue by defining the device
driver and then assigning a NUA to each machine. From the first menu of the
SMIT interface, select:
62
RS/0000 X.25 Cookbook
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/2 A da
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Add a Port
Or use the SMIT fastpath cx25str_mp (with X.25 Co-Processor/2) or px25str_mp
(with a Portmaster Adapter).
kili
fili
Add an X.25 Port
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Add an X.25 Port
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
twd0
[0]
[3106000001]
[other public]
[]
Parent adapter driver
* PORT number
* Local network user address (NUA)
* Network identifier
Country prefix
+
#
+
#
Parent adapter driver
* PORT number
* Local network user address (NUA)
* Network identifier
Country prefix
[Entry Fields]
twd0
[0]
[3106000002]
[other public]
[]
+
#
+
#
The AIX-generated commands are:
#mksx25 -c port -s star -t stx25 -p ′ twd0′ -w ′ 0 ′
-a local_nua=′3106000001′ -a network_id=′ 5
#mksx25 -c port -s star -t stx25 -p ′ twd0′ -w ′ 0 ′
-a local_nua=′3106000002′ -a network_id=′ 5
Notes:
•
Network User Address (NUA): This is required to initialize the X.25 adapter.
Don′t start the NUA with three zeroes.
•
Field Network Identifier: Use other public if your NUA adheres to CCITT X.212
standards or other private if your NUA is purely arbitrary.
•
Again, please be sure to configure the primary machine as DTE (the calling
one) and the secondary machine as DTE (the listening one).
You have now set up all necessary X.25 parameters for a test environment. To
have a convenient list of the X.25 parameters of your system that will help you if
any problem occurs during the connection tests, type:
# lsattr -E -H -l sx25a0 | grep -v pvc
The output includes:
..
.
network_id
local_nua
in_svc
num_in_svcs
in_out_svc
num_in_out_svc
5
3106000001
0
0
1
20
Network identifier
Network User Address
Lowest logical channel number for an incoming SVC
Number of logical channels for incoming SVCs
Lowest logical channel number for an two-way SVC
Number of logical channels for two-way SVCs
..
.
The grep filter is used to eliminate the PVC parameters from the list by
suppressing all the lines containing the string “pvc.”
Chapter 3. X.25 LPP Installation and Setup
63
3.4 Returning to the Default Configuration Parameters
If it is necessary to start again, delete the X.25 port definition from AIX using the
following commands:
If you are using COMIO, then first delete it using:
rmdev -l ′ x25s0′
Then you may remove the X.25 port using the following command:
rmdev -d -l sx25a0
If you use COMIO and try to delete the sx25a0 directly, you will get the following
error message:
Method error (/usr/lib/methods/ucfgsx25):
0514-029 Cannot perform the requested function because a
child device of the specified device is not in a correct state
3.5 Configuring V.25bis Dialing
If you are going to use V.25bis, you must:
1. Configure the Connection Type as V25bis.
2. Configure the Call Establishment Method as Addressed or Direct.
When addressed is specified on outgoing calls, the number must be supplied.
On incoming calls, V.25bis commands are used to notify the DTE.
When direct is specified on outgoing calls, the number is stored in the
modem. On incoming calls, the calling indicator is used to notify the DTE.
3. If you are using the Addressed V25bis Call Establishment Method, then you
must fill the Phone Number or Address to Call attribute.
4. Set the Maximum Connection Delay attribute to be long enough for modems to
perform handshaking/training operations.
5. Set the Enable/Disable DSR polling attribute to Enable.
For example, if you want to configure V.25bis with the addressed call
establishment method and phone number 2291992, select from SMIT for the
Co-Processor/2 adapter:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/2
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Change / Show Characteristics of Port
→
Change / Show General Parameters
64
RS/0000 X.25 Cookbook
Change / Show General Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[MORE...14]
******************
Use X.32 XID Exchange
X.32 XID Identity
X.32 XID signature
[Entry Fields]
[no]
[]
[]
Dial-Up Configuration
********************
Connection Type
V25bis Call Establishment Method
Phone Number or Address to Call
Maximum Connection Delay
Enable/Disable DSR Polling
DSR polling timeout
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
+
[V25bis]
[Addressed]
[2291992]
[30]
[enable]
[30]
F3=Cancel
F7=Edit
Enter=Do
+
+
#
+
#
F4=List
F8=Image
3.6 Configuring ISA X.25 Adapters
In this section, we will provide some information on how to set up an X.25 ISA
adapter. In our test, we use RISC Systems/6000 Model 40P with AIX 4.1.4. For
more information, please refer to Managing AIX V4 on PCI-Based RISC
System/6000 Workstations (40P/43P) SG24-2581-00. We used IBM Realtime
Interface Co-Processor Multiport Adapter Model 2. Detail information about this
card could be found in the Guide to Operations which comes with it.
The IBM X.25 Co-Processor Multiport Adapter/2 is equipped with switches to set
the operating system parameters. The procedure that is described in this section
shows you how to set the operating system parameters at hardware level and at
AIX level.
3.6.1 Configuring ISA X.25 Adapters at the Hardware Level
Before you install the ISA X.25 Co-Processor/2 adapter in your computer, first
you need to configure the switches on the card. Please keep in mind that some
parameters are set at the hardware and AIX level and they must match. Record
every setting that you make.
The first three switches are used to configure interrupt level. For more detailed
information on the other switches, please refer to the adapter manual. It also
depends on the positions of the adapter, whether it is the first, second or third
ISA adapter in your computer. The following explanation is only a guide.
Table 6 (Page 1 of 2). Interrupt Level Switch Positions
Dip Switch 1
Dip Switch 2
Dip Switch 3
Interrupt Level
down
down
down
3
up
down
down
4
Chapter 3. X.25 LPP Installation and Setup
65
Table 6 (Page 2 of 2). Interrupt Level Switch Positions
Dip Switch 1
Dip Switch 2
Dip Switch 3
Interrupt Level
down
up
down
7
up
up
down
2 or 9
down
down
up
10
up
down
up
11
down
up
up
12
up
up
up
15
Table 7. X.25 Adapter: Switch Block 1
Dip Switch #
First Adapter
Second Adapter
Third Adapter
4
down
down
down
5
down
up
down
6
down
down
up
7
down
down
down
8
down
down
down
9
down
down
down
10
down
down
down
Notes:
•
We use up and down instead of off and on respectively.
•
Dip switch 4 is factory set to indicate the size of RAM installed on the
adapter. Verify that the position of this switch is down to reflect a RAM size
of 512 KB.
•
Dip switch 9 indicates whether a one-edge (62-pin) or a two-edge (62-pin and
36-pin) connector is used to hold your adapter.
•
Dip switch 10 sets the bus width and should generally be set to 8-bit.
down=8-bit / up=16-bit
1. Install your ISA X.25 adapter in the computer.
2. Insert the SMS (System Management Services) diskette into the diskette
drive and turn the computer on.
3. As soon as the first screen appears, press the F4 key.
4. Use the Up and Down arrow keys to select Test the Computer and press
Enter. A list similar to the following will appear:
66
RS/0000 X.25 Cookbook
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
[]Test
All Sybsystems
System Board
Memory
Keyboard
Mouse
SCSI Adapter
Diskette
Serial Port
Parallel Port
Performance Video
Token-Ring Adapter 1
Ethernet Adapter I/O 0x240
Ethernet Adapter I/O 0x300
X.25 Adapter I/O Addr 0x2A0
X.25 Adapter I/O Addr 0x6A0
5. Use the spacebar to select or deselect the device.
6. Press F6 to run the test.
If the test is successful, continue with Configuring ISA X.25 Adapters at AIX
Level.
3.6.2 Configuring ISA X.25 Adapters at the Software Level
After successfully configuring the ISA X.25 Adapter at the hardware level, you
will need to configure those parameters to the AIX.
1. Log in as root.
2. Use SMIT to add your adapter:
smit c1xmpxa
→
Add an X.25 Adapter
Select the appropriate bus and fill in the following SMIT panel:
Add an X.25 CoProcessor/1 Adapter
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
Description
Parent Adapter
* ISA Virtual Connection
ISA Interrupt Level
Interrupt Priority
BUS IO Address
BUS Memory Address
Window Size
F1=Help
F5=Reset
F9=Shell
bus1
[0]
[11]
2
[0x2A0]
[0xE0000]
0x2000
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
3. Verify whether the X.25 adapter is available:
lsdev -Ccadapter -s isa
If the adapter has been successfully configured, the system will display
device information similar to the following:
ampx0 Available 00-1X
N/A
Chapter 3. X.25 LPP Installation and Setup
67
4. Verify that the attributes are customized for the adapter. For example, for the
device ampx0 enter:
lsattr -l ampx0 -E
A list similar to the following will appear:
bus_intr_lvl
intr_priority
bus_io_addr
bus_mem_addr
window_size
11
2
0x2A0
0xE0000
0x20000
Bus Interrupt Level
Interrupt Priority
Bus IO address
Bus memory address
Bus memory window size
True
False
True
True
False
5. Now, you have to configure the X.25 device driver. Use the following SMIT
sequence:
smit cx25str_dd
→
Add a Device Driver
Select the parent adapter, and press Enter.
Enter the following command to verify the availability of the driver:
lsdev -Cl twd0
A line similar to the follwing should appear:
twd0 Available 00-1X-00 ARTIC Adapter Driver
6. After the driver has become available, you can configure the X.25 LPP port.
For this task, you will need to obtain the details about your X.25 network
subscription. Contact your X.25 network provider or your X.25 network
administrator.
To start the X.25 port configuration, enter:
smit cx25str_mp
→
Add Port
Select the parent adapter driver, and provide the required information in the
SMIT panel.
7. Enter the following command to verify whether the X.25 port has become
available:
lsdev -C -t stx25 -H
The system will dispaly information similar to the following:
name
status
location
description
sx25a0 Available 00-1X-00-00 X.25 Port
3.7 X.25 Facilities
In this section, we will provide some details about the function and use of the
main X.25 facilities. For more information on facilities, see: 1.7.1, “Definition” on
page 15 and Appendix E, “Facilities” on page 275.
3.7.1 Facilities Requested by the DTE
Only X.25 facilities included in the network subscription may be used. Facilities
are coded in the layers above the packet layer. The IBM-provided applications
xtalk, TCP/IP, and SNA Server allow the user to optionally define a facility
request that will be inserted in the call packet.
68
RS/0000 X.25 Cookbook
X.25 facilities are configured using SMIT.
3.7.1.1 Configuring Fast Select Mode
Fast Select is an optional service of X.25 that, if configured on both DTEs, allows
the transfer of up to 128 octets of user data within the call request. Configuration
options for the Fast Select facility are:
•
Allow
•
Allow only incoming calls
•
Allow only outgoing calls
•
Allow only if not billed
•
Forbid
The default is allow, but depending on your network subscription, you can
change it. For example, if you want to change Fast Select mode to forbid, select
from SMIT for the Co-Processor/2 adapter:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-rocessor/2 or Multiport/2
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Change / Show Characteristics of Port
→
Change / Show Packet Parameters
Or use the fastpath: smit x25str_mp_csp_p_sel
Change / Show Packet Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[MORE...37]
R20 retransmission
R22 retransmission
R23 retransmission
R25 retransmission
R27 retransmission
R28 retransmission
[Entry Fields]
count
count
count
count
count
count
restart timer
reset timer
clear timer
window rotation timer
reject timer
registration timer
Packet-Level Features
**********
Fast select mode
D-bit
Reverse charging
Maximum facility field length
Interrupt data size
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
[3]
[3]
[3]
[0]
[0]
[1]
+#
+#
+#
+#
+#
+#
[forbid]
[allow]
[allow]
[109]
[32]
+
+
+
+#
+#
F4=List
F8=Image
The AIX-generated command is:
chdev -l ′ sx25a0′ -a fs_mode=′ 0 ′
Chapter 3. X.25 LPP Installation and Setup
69
3.7.1.2 Configuring Reverse Charging
Coming or outgoing calls can have a facility requesting that the receiving party
pays for the call. Configuration options for the Reverse Charging facility are:
•
Allow
•
Allow only if not billed
•
Forbid
The default is allow, but depending on your network subscription you can
change it. For example, if we want to change Reverse Charging to forbid, we
would select from SMIT main menu for a Co-Processor/2 adapter:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/2
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Change / Show Characteristics of Port
→
Change / Show Packet Parameters
Or use the fastpath: smit x25str_mp_csp_p_sel
Change / Show Packet Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[MORE...37]
R20 retransmission
R22 retransmission
R23 retransmission
R25 retransmission
R27 retransmission
R28 retransmission
[Entry Fields]
count
count
count
count
count
count
restart timer
reset timer
clear timer
window rotation timer
reject timer
registration timer
Packet-Level Features
**********
Fast select mode
D-bit
Reverse charging
Maximum facility field length
Interrupt data size
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
The AIX generated command is:
chdev -l ′ sx25a0′ -a rev_charge=′ 0 ′
70
RS/0000 X.25 Cookbook
F3=Cancel
F7=Edit
Enter=Do
[3]
[3]
[3]
[0]
[0]
[1]
+#
+#
+#
+#
+#
+#
[allow]
[allow]
[forbid]
[109]
[32]
+
+
+
+#
+#
F4=List
F8=Image
3.7.1.3 Configuring Maximum Facility Field Length
You can configure the maximum facility field size in call and clear registration
packets. For compliance with CCITT 1984 and later, the facility field length should
be set to 109. Use a value of 63 for networks of prior to CCITT 1984. For
example, if we want to change the maximum facility size, we select from SMIT
for a coprocessor adapter:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/2
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
Change / Show Characteristics of Port
→
Change / Show Packet Parameters
Or use the fastpath: smit x25str_mp_csp_p_sel
Change / Show Packet Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[MORE...37]
R20 retransmission
R22 retransmission
R23 retransmission
R25 retransmission
R27 retransmission
R28 retransmission
[Entry Fields]
count
count
count
count
count
count
restart timer
reset timer
clear timer
window rotation timer
reject timer
registration timer
Packet-Level Features
**********
Fast select mode
D-bit
Reverse charging
Maximum facility field length
Interrupt data size
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
[3]
[3]
[3]
[0]
[0]
[1]
+#
+#
+#
+#
+#
+#
[allow]
[allow]
[allow]
[63]
[32]
+
+
+
+#
+#
F4=List
F8=Image
The AIX generated command is:
chdev -l ′ sx25a0′ -a fac_length=′ 6 3 ′
3.7.2 More on Configuring Facilities
There are examples of defining facilities for TCP/IP and SNA in 7.3, “Requesting
the Use of a Facility with TCP/IP” on page 145 and 8.3.6.4, “Defining X.25
Optional Facilities Profile” on page 168. Facilities formats can be found in
Appendix E, “Facilities” on page 275.
Chapter 3. X.25 LPP Installation and Setup
71
72
RS/0000 X.25 Cookbook
Chapter 4. Tools
In this chapter, we will present the tools:
•
xtalk
•
x25mon
•
x25status
•
xroute
More details are available in AIXLink/X.25 Version 1.1 for AIX: Guide and
Reference manual.
4.1 The xtalk Tool
Xtalk can be used as a tool or as a simple application.
4.1.1 Description
The xtalk tool enables you to initiate or receive calls over SVCs and
communicate with remote hosts by exchanging messages and files. Xtalk is a
tool that can be used as a sample application to verify a connection across an
X.25 network. The xtalk tool can also be used to test an X.25 network before
application programs such as TCP/IP, SNA/X.25, a terminal emulator or a PAD
are configured.
Note: The xtalk tool is implemented over COMIO emulation and so can be used
only over ports that have COMIO emulation configured.
4.1.2 Overview and Fast Path
In our test, we will use xtalk to:
•
Start xtalk
•
Define a remote host
•
Establish a connection over an SVC
•
Exchange messages
Figure 27. xtalk Test
 Copyright IBM Corp. 1996
73
Testing an SVC Communication with xtalk
1. On fili, load xtalk to listen to the IBMXTALK entry in the routing table:
# xtalk -s -l IBMXTALK
2. On kili:
•
Load xtalk:
# xtalk -s -l IBMXTALK
•
Use the ADD function to create an entry in the address list for fili;
enter its NUA.
•
Use the TALK function to call fili.
3. On fili, accept the incoming call, and then press F2.
4. On kili, press F2 and enter a message. It is transmitted on the network
and then displayed on fili.
Notes:
•
If you have only one system, open two windows (or two sessions). In the
first, start one copy of xtalk that will correspond to the called machine and
will listen for incoming calls whose characteristics are defined in the routing
table entry IBMXTALK:
# xtalk -s -l IBMXTALK
In the other window, start xtalk without a routing parameter:
# xtalk -s
Ignore the warning message: You cannot receive incoming calls... by
pressing Esc. You can now proceed from this window the same way as
explained for the system kili.
•
Xtalk cannot be used to test PVCs. Use the sample programs instead. (See
Chapter 6, “APIs: COMIO, NPI and DLPI” on page 117.)
4.1.3 The xtalk Command
The xtalk command provides a panel-driven environment where you can make
or receive a virtual call and then either talk to another person by typing
messages on a panel, or send and receive files. You can store the details of the
systems you want to communicate with under a symbolic name in an address
list. The xtalk command allows you to view, change, add or delete entries of
this list.
Syntax:
xtalk [ -n ] [ -l EntryName &] [ -q | -s ]
Flags:
74
-n
Runs the xtalk process in the background to listen for incoming calls.
-l
Listens for calls for the routing list entry specified by EntryName .
-q
Displays the title panel for two seconds.
-s
Does not display the title panel.
RS/0000 X.25 Cookbook
Related files:
/etc/xtalk.names
Contains the systemwide xtalk address list, which can
be used by all users on the system to route outgoing
calls.
$HOME/xtalk.names
Contains the individual user′s xtalk address list used to
route outgoing calls.
/etc/xrt.names
Contains the X.25 routing list, used to route incoming
calls with the COMIO interface.
/OtherDTEname.log
Names the message logging file. OtherDTEname
specifies the address list name of the DTE with whom
messages were exchanged, or the last eight digits of its
network user address.
Introducing the xtalk Command
The xtalk command has several features that are analogous to using a
telephone. To have a conversation or transfer files, one party must first make a
call and the other party must receive and accept the call. Either party can end
the call at any time. With xtalk you can:
•
•
•
•
•
•
Listen for calls
Make a call
Receive a call
Have a conversation
Transfer files
End a call
You can run the xtalk command in the background to listen for calls and notify
you when they arrive. When a call arrives, you can start xtalk again in the
foreground and then choose whether to accept or reject the call.
To have a conversation, each party types messages; both your messages and
the other party′s messages appear on your display. You can use a log file to
record the messages you exchange during a conversation.
4.1.4 Testing Communication with xtalk
You can use the xtalk command to test X.25 communications; this test only
applies for communicating RISC System/6000s.
4.1.4.1 Start xtalk on fili
First, start xtalk on fili to listen to the incoming call from kili.
# xtalk -s -l IBMXTALK
IBMXTALK is the identification of a record in the routing table giving the
characteristics of the incoming calls that must be routed to the xtalk application.
This name and the corresponding routing table entry are already defined in the
system, and you do not have to worry about them. The function of the routing
table and the way to customize it are defined in this chapter when we describe
the use of the xroute tool.
After a while, this is what is displayed:
Chapter 4. Tools
75
┌──────────────────────────────────────────────────────────────────────────────┐ │X.25 Communications XTALK
│
├──────────────────────────────────────────────────────────────────────────────┤
│
TALK
ADD
BROWSE
CHANGE
DELETE
QUIT
│
├──────────────────────────────────────────────────────────────────────────────┤
│You can make and receive calls
│
├──────────────────────────────────────────────────────────────────────────────┤
│ Name
Port
NUA
Extension
│
│
│
4.1.4.2
Start xtalk on kili
Start xtalk on kili the same way as on fili:
# xtalk -s -l IBMXTALK
Create an Entry for fili in kili′ s address list:: Each user you can talk to over an
X.25 network has a network user address (similar to a telephone number). The
xtalk command maintains a system address list that is available to all users, so
users can make calls without knowing another user′s network address. Each
user can also choose to keep a local address list containing modifications and
additions to the system address list. An entry for a user in your local address list
overrides the entry for the same user in the system address list.
The following screen dialogs show how to add an entry for fili in kili′s system
address list, which you will use later to call it. This is like maintaining a phone
directory for valid NUAs that a machine can dial to or can be dialed from.
The xtalk command will display a dialog screen, from which you can choose the
ADD option to create a new entry in the address list:
┌──────────────────────────────────────────────────────────────────────────────┐ │X.25 Communications XTALK
│
├──────────────────────────────────────────────────────────────────────────────┤
│
TALK
ADD
BROWSE
CHANGE
DELETE
QUIT
│
├──────────────────────────────────────────────────────────────────────────────┤
│You can make and receive calls
│
├──────────────────────────────────────────────────────────────────────────────┤
│ Name
Port
NUA
Extension
│
│
┌──────────────────────────────────────────────────────────────────────────────┐ │X.25 Communications XTALK
ADD │
├──────────────────────────────────────────────────────────────────────────────┤
│ Name
==>FILI
│
│ Port
==>x25s0
│
│ Address
==>3106010761
│
│ Extended Address
==>
│
│ Facilities
==>
│
├───────────────────────────────────────────────────────────────┬──────────────┤
│ Press Enter when finished
│ Esc = Cancel │
└───────────────────────────────────────────────────────────────┴──────────────┘
In the same manner, you will add the kili entry to fili′s address list so that the
NUA in incoming calls from kili will be translated into the name kili and listed on
the screen when a call occurs.
76
RS/0000 X.25 Cookbook
Calling fili:: You are now ready to make a call. By moving the highlighted zone
with the vertical cursor movement keys, select the system you want to call.
From the menu screen, select TALK:
┌──────────────────────────────────────────────────────────────────────────────┐ │X.25 Communications XTALK
│
├──────────────────────────────────────────────────────────────────────────────┤
│
TALK
ADD
BROWSE
CHANGE
DELETE
QUIT
│
├──────────────────────────────────────────────────────────────────────────────┤
│You can make and receive calls
│
├──────────────────────────────────────────────────────────────────────────────┤
│ Name
Port
NUA
Extension
│
│
│
│ Your address list:
│
│
│
│
│
│
│
│
│
│
│
│
│
│ System Address List:
│
│
│
│FILIx25s03106010761
│
│
│
│
├──────────────────────────────────────────────────────────────────────────────┤
│
F1 = Help
F3 = Shell
│
└──────────────────────────────────────────────────────────────────────────────┘
Then press Enter to select fili:
┌──────────────────────────────────────────────────────────────────────────────┐ │X.25 Communications XTALK
TALK │
├──────────────────────────────────────────────────────────────────────────────┤
│ Name/NUA
==>FILI
│
│ Port
==>x25s0
│
├───────────────────────────────────────────────────────────────┬──────────────┤
│ Press Enter when finished
│ Esc = Cancel │
├───────────────────────────────────────────────────────────────┴──────────────┤
Then press Enter again to make the call.
4.1.4.3
Exchanging Messages between kili and fili
On kili, the next screen shows that a call is in progress while on fili, a message
shows that there is an incoming call.
kili
fili
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
WAIT │
├──────────────────────────────────────────────────────────────────────────────┤
│ Making call to FILI ( 3106010761 on x25s0)
│
│ Press Esc to cancel the call
│
├───────────────────────────────────────────────────────────────┬──────────────┤
│
│
│
│
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
INFORMATION │
├──────────────────────────────────────────────────────────────────────────────┤
│Incoming call from KILI (3106010760 on x25s0)
│
│
│
│
ACCEPT
REJECT
│
│
│
├──────────────────────────────────────────────────────────────────────────────┤
Choose the ACCEPT option from the menu on fili to start a conversation between
the two machines. Once the call has been accepted, a menu screen appears
that allows you to send and receive messages and files.
Chapter 4. Tools
77
kili
fili
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
Message logging is OFF │
├──────────────────────────────────────────────────────────────────────────────┤
│ Connected to FILI (3106010761 on x25s0)
│
├──────────────────────────────────────────────────────────────────────────────┤
│
│
│ TRANSFER FILE
│
│
│
│ BEGIN LOGGING
│
│
│
│ END LOGGING
│
│
│
│ CHANGE LOG FILENAME
│
│
│
│ QUIT CALL
│
│
│
│
│
│
│
│
│
│
│
│
│
├──────────────────────────────────────────────────────────────────────────────┤
│
F1 = Help
F2 = Messages
F3 = Shell
│
└──────────────────────────────────────────────────────────────────────────────┘
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
Message logging is OFF │
├──────────────────────────────────────────────────────────────────────────────┤
│ Connected to KILI (3106010760 on x25s0)
│
├──────────────────────────────────────────────────────────────────────────────┤
│
│
│ TRANSFER FILE
│
│
│
│ BEGIN LOGGING
│
│
│
│ END LOGGING
│
│
│
│ CHANGE LOG FILENAME
│
│
│
│ QUIT CALL
│
│
│
│
│
│
│
│
│
│
│
│
│
├──────────────────────────────────────────────────────────────────────────────┤
│
F1 = Help
F2 = Messages
F3 = Shell
│
└──────────────────────────────────────────────────────────────────────────────┘
The F2 key is a toggle key between a dialog screen to enter and receive
messages, and the menu shown above. We press F2 on kili to send the Hello
world message to fili. After having been transported on the X.25 network, the
message is displayed on fili:
kili
fili
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
Message logging is OFF │
├──────────────────────────────────────────────────────────────────────────────┤
│ Connected to FILI (3106010761 on x25s0)
│
├──────────────────────────────────────────────────────────────────────────────┤
│
│
│ Hello World!
│
│
│
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
Message logging is OFF │
├──────────────────────────────────────────────────────────────────────────────┤
│ Connected to KILI (3106010760 on x25s0)
│
├──────────────────────────────────────────────────────────────────────────────┤
│
│
│ Hello World!
│
│
│
│
│
If you have not successfully completed this test, go to Chapter 9, “X.25 Problem
Determination” on page 181.
Transferring Files: To transfer a file with xtalk, one user sends the file, and the
other can choose to accept or reject it. If a file of the same name already exists
on the recipient′s system, the recipient can choose to append or overwrite the
existing file, or save the transferred file under a new name.
4.1.5 Requesting the Use of a Facility with xtalk
In the following example, we will explain how to reverse the charges during a
virtual call made by using xtalk. (We assume that the called number has
subscribed to the reverse charging acceptance facility.)
First, we look at E.1, “Supported Facilities for X.25 Communications” on
page 275, which explains how to code a facility request. The code for reversing
the charges is:
Value
Description
0x01
Reverse charging or fast select
0x01
Reverse charging requested
Then, after having started xtalk, use the CHANGE panel to add this facility
request in the definition of the X.25 host fili:
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RS/0000 X.25 Cookbook
┌──────────────────────────────────────────────────────────────────────────────┐ │ X.25 Communications XTALK
CHANGE │
├──────────────────────────────────────────────────────────────────────────────┤
│ Name
==>FILI
│
│ Port
==>x25s0
│
│ Address
==>3106010761
│
│ Extended Address
==>
│
│ Facilities
==>0101
│
├──────────────────────────────────────────────────────────────┬───────────────┤
│ Press Enter when finished.
│ Esc = Cancel │
└──────────────────────────────────────────────────────────────┴───────────────┘
Now, start x25mon -p -n sx25a0 in another window and make a call to fili using
the call function of xtalk; here is what we will see on the trace:
sx25a0 PS 0x0014 CALL
dN la:10 lf:2
ld:1 AA31060107613106010760020101FD
If we compare this to the trace without the facility request:
sx25a0 PS 0x0014 CALL
dN la:10 lf:0
ld:1 AA3106010761310601076000FD
we can see that xtalk has generated a facility length of 02 and has inserted it
with the facility request 0180 between the NUA block and the CUD.
4.2 The x25mon Tool
The x25mon command replaces the xmonitor command used in previous AIX X.25
products.
4.2.1 Description
The x25mon tool traces the frame or packet traffic of an X.25 port, and the report
is sent to stdout .
When using the x25mon application, the display that is used to show the data
must keep up with the rate of data being received. If running on a slow display,
such as an ASCII terminal, the x25mon output should be directed to a file. This
keeps system resources from being depleted and terminating the data transfer.
With AIXLink/X.25 Version 1.1.3, two new x25mon flags, -i and -d, are offered and
the length of data is indicated via an l: in the trace for both packet and frame
layers.
4.2.2 Using the x25mon Tool
Running an X.25 line trace via x25mon on a system with heavy X.25 traffic can
negatively impact X.25 throughput due to additional processing overhead and
adapter memory resource constraints. Thus, tracing is recommended for
problem isolation activity rather than as a matter of routine.
Prior to the X.25 Version 1.1.3 enhancement, all packet and frame data was
saved in the x25mon trace information and trace packets were discarded, when
necessary, to keep up with the incoming traffic. When this happened, the trace
output was flagged with:
PK_LMS_IND
1:0 missed: xx
where xx is the number of packets missed.
Chapter 4. Tools
79
With X.25 Version 1.1.3, users can lessen the trace burden by saving only a
portion of the contents of the data packets. Two new flags, -i and -d, allow
users to specify the maximum number of frame and packet level data bytes to
save in the trace. In addition, all trace data will be captured, regardless of
network load. That is, the X.25 device driver will no longer sacrifice trace data in
order to service incoming traffic.
The -i flag indicates the info frame trace size. Valid value ranges are from 0 to
5003. If this flag is not specified, 512 bytes is assumed. The -d flag sets the data
packet trace size. Valid value ranges are from 0 to 4096. If not specified, all data
is captured in the trace.
The following command will trace the packet and frame layers of the sx25a0 port,
showing the first 5 bytes of data in the packet layer and the first 10 bytes of data
within the frame layer. The user will know that the trace shows only a portion of
the actual content because bytes beyond the number specified will be annotated
with: ″..″.
x25mon -p -d 5 -f -i 10 -n sx25a0
Limiting the number of bytes saved in the trace is extremely important, as it
affects both performance and memory resource utilization. It is highly
recommended that frame traces be limited to less than 512 bytes. Running with
larger traces may result in severe adapter memory constraints.
Generally, the x25mon tool is issued as:
x25mon -p -f -n <portname>
This will trace both the frame and packet levels. We will show x25mon as separate
frame and packet traces to better identify the flags.
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RS/0000 X.25 Cookbook
4.2.2.1 Packet Level
First, open a new window or a new session and start x25mon at the packet level
with: x25mon -p -n sx25a0. You should normally get the following:
X.25 Monitor sx25a0
10:33:55 sx25a0 PR
310601076200
10:33:55 sx25a0 PS
10:33:55 sx25a0 PR
10:33:55 sx25a0 PR
049
10:33:55 sx25a0 PS
10:33:55 sx25a0 PR
10:33:55 sx25a0 PS
1
2
0x0004 CALL
dY la:10 lf:0 ld:0 AA3106010760
0x0004 CF CALL
0x0004 DATA
0x0004 DATA
dN
pr:0 ps:0 dN mN qN l:8 544556454 4E4543
pr:0 ps:1 dY mN qN l:10 534352415649472
0x0004 RR
0x0004 CLEAR
0x0004 CF CLEAR
pr:2
c:0 d:0
3
4
5
6
7
The keys to understand this trace are the following:
•
Column one:
−
•
Column two:
−
•
•
PS
Data packet type sent
PR
Data packet type received
Column four:
Indicates the logical channel number
Column five:
−
•
X.25 port traced
Column three:
−
•
Time stamp
Specifies the type of X.25 packet
Column six:
−
Specifies the different flags of the packet level:
- d : D bit set to Yes or No
- q : Q bit set to Yes or No
- m : M bit set to Yes or No
- l : Specifies the lengths, given in number of bytes they take up :
•
•
la : length of the NUAs
•
lf : length of the facilities
•
ld : length of the call user data
•
l : length of data in the data packet
Column seven:
−
Specifies the data portion of the packet.
Chapter 4. Tools
81
4.2.2.2 Frame Level
First, open a new window or a new session and start x25mon at the frame level
with: x25mon -f -n sx25a0. You should normally get the following:
X.25 Monitor sx25a0
10:34:26 sx25a0 FR
10:34:26 sx25a0 FS
10:34:26 sx25a0 FR
10:34:26 sx25a0 FR
10:34:26 sx25a0 FS
10:34:26 sx25a0 FR
10:34:26 sx25a0 FS
10:34:27 sx25a0 FR
1
2
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
INFO
INFO
INFO
INFO
INFO
INFO
INFO
RR
4
5
3
a:1
a:3
a:1
a:1
a:3
a:1
a:3
a:3
p:0
p:0
p:0
p:0
p:0
p:0
p:0
p:0
ns:6
ns:0
ns:7
ns:0
ns:1
ns:1
ns:2
nr:3
nr:0
nr:7
nr:1
nr:1
nr:1
nr:2
nr:2
50040BAA31060107603106010
10040F
100400544556454E4E4543
5004025343524156494720494
100441
1004130000
100417
6
7
The keys to understand this trace are the following:
•
Column one:
−
•
Column two:
−
•
•
FS
Data frame type sent
FR
Data frame type received
Column four:
Indicates the logical channel number
Column five:
−
•
X.25 port traced
Column three:
−
•
Time stamp
Specifies the frame type
Column six:
−
Specifies the different flags of the frame level:
- a : Gives the frame address DCE(3) or DTE(1)
- p : Gives the setting of the poll/final bit
- n : Gives the settings of the send and receive counters
•
Column seven:
−
Information field of the frame level
4.3 The xroute Tool
The xroute tool is used to manage the COMIO routing table.
4.3.1 The Routing Table
All incoming calls made over COMIO emulation are routed to the applications by
the X.25 device driver using the X.25 routing table. If the incoming call matches
the criteria defined in this table for a specific application, the call will be routed
to that application. A routing table is not needed if you are using only PVCs. The
applications not based on COMIO but on the NPI API get their routing with the
STREAMS implementation (N_BIND_REQ primitive).
82
RS/0000 X.25 Cookbook
An application listening for an incoming call is associated with an entry name in
the routing table. This entry specifies the criteria that must be satisfied for the
application program to receive an incoming call.
The call user data (CUD) field of the call packet is generally used for routing but
other conditions may also be tested, such as:
•
The network address of the caller
•
A subaddress in the called DTE address
•
The attachment that has received the call
The xroute tool is used to manage the COMIO X.25 routing table so it is usable
only for xtalk, SNA based applications and all applications written over the
previous X.25 API library or over the previous X.25 device driver supported in
AIX V3. For applications that do not use the COMIO emulation interface, like
TCP/IP and NPI, the xroute tool is unnecessary. So the xroute tool works with
X.25 ports that have COMIO emulation configured.
4.3.2 Updating the X.25 Routing Table with the xroute Tool
The routing table is stored in the /etc/xrt.names file. A d
provided that may be updated with the xroute command.
efault file is
To use xroute, log on as root and type:
# xroute -s
You will get the X.25 Communications XROUTE menu:
┌──────────────────────────────────────────────────────────────────────────────┐ │ X.25 Communications XROUTE
│
├──────────────────────────────────────────────────────────────────────────────┤
│
ADD
BROWSE
CHANGE
DELETE
QUIT
│
├──────────────────────────────────────────────────────────────────────────────┤
│ Entry name Port
Called Subaddress
CUD
│
│
│
│ IBMELLC
*
*
C6
│
│ IBMELLC
*
*
CE
│
│ IBMPSH
*
*
C2
│
│ IBMPSH
*
*
CA
│
│ IBMQLLC
*
*
C3
│
│ IBMQLLC
*
*
CB
│
│ IBMSAMP
*
*
*
│
│ IBMTCP0
x25s0
*
CC
│
│ IBMXTALK
x25s0
*
FC
│
│ IBMXTALK
*
*
FD
│
│
│
│
│
│
│
│
│
├──────────────────────────────────────────────────────────────────────────────┤
│
F1 = Help
F3 = Shell
│
└──────────────────────────────────────────────────────────────────────────────┘
This is the default routing table with predefined entries for SNA, TCP/IP, the
sample program and xtalk. The first six entries correspond to X.25/SNA
protocols:
Chapter 4. Tools
83
•
IBMELLC identifies the SNA-Enhanced logical link control used for
peer-to-peer
•
IBMPSH identifies the physical services header LLC used with the IBM-5793
network interface adapter (NIA)
•
IBMQLLC identifies the SNA-qualified logical link control
The two CUDs associated with each of these protocols identify their version, 1980
or 1984/88.
To change a routing list entry, move the cursor to the entry name you would like
to change and type c for change.
The following screen will appear:
┌──────────────────────────────────────────────────────────────────────────────┐ │ X.25 Communications XROUTE
CHANGE │
├──────────────────────────────────────────────────────────────────────────────┤
│ Entry name
==>IBMXTALK
│
│ User name
==>*
│
│ X.25 port
==>*
│
│ Calling Address
==>*
│
│ Called Subaddress
==>*
│
│ Calling Address Ext ==>*
│
│ Called Address Ext ==>*
│
│ Call User Data
==>FD
│
│
==>
│
│
==>
│
│
==>
│
│ Priority (1-3)
==>1
│
│ Action (R,F)
==>R
│
├──────────────────────────────────────────────────────────────┬───────────────┤
│ Press Enter when finished.
│ Esc = Cancel │
└──────────────────────────────────────────────────────────────┴───────────────┘
│
│
│
│
├──────────────────────────────────────────────────────────────────────────────┤
│
F1 = Help
F3 = Shell
│
└──────────────────────────────────────────────────────────────────────────────┘
The fields are:
Entry Name
Name of the entry that will be used by the listening
program to refer to this set of criteria.
Call User Data
This is a part of the data received in an incoming call
packet. It can be used for any purpose, but it often
specifies the protocol. Only the first 64 bytes of the CUD
can be used by xroute.
User Name
This is the login name of the user who is allowed to start
applications listening for incoming calls associated with
this entry. An * means that any user can listen for calls
using this entry. A user whose login name does not match
this entry is not allowed to listen for calls corresponding to
it.
For example, your routing list entry contains the user
name marcel :
84
RS/0000 X.25 Cookbook
┌──────────────────────────────────────────────────────────────────────────────┐
│ X.25 Communications XROUTE
CHANGE │
├──────────────────────────────────────────────────────────────────────────────┤
│ Entry name
==>IBMXTALK
│
│ User name
==>marcel
│
If you try to start the command xtalk -l IBMXTALK as the
user root, you will get an error message such as:
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
ERROR 121 │
├──────────────────────────────────────────────────────────────────────────────┤
│ CIO Status 79 - X25_AUTH_LISTEN
│
│ You cannot listen to this name, because the routing list entry has
│
│ a userid which excludes the user running the application.
│
│
│
├─────────────────────────────────────────────────────────────┬────────────────┤
X.25 Port
The name of the X.25 port associated with the application
for which the call is intended. This can be set to * to
indicate any port.
Calling Address
The application will receive incoming calls only from this
calling address. An * at the end of this entry indicates that
any digits are acceptable in the remainder of the address.
Another NUA trying to call this application will be rejected.
Called Subaddress
You can add additional digits to the end of an NUA up to
the 15-digit limit. This subaddress can be used to route a
call internally within a node. For example, calling
310601076101 may be routed to fili with a subaddress of 01.
This parameter can be set to * to indicate any subaddress.
Calling Address Ext
In X.25 (1984), it is possible to specify up to 40 additional
digits of address. This can be set to * for any address
extension.
Called Address Ext
See calling address extension.
Priority (1-3)
If two applications need to listen to the same routing
information, the priority field specifies who should receive
the call if both are listening. For example, IBMSAMP is
defined as listening to any condition * in all fields but with
the lowest priority (3). Thus, a background daemon could
be written that listened to IBMSAMP and logged any
incoming call that is not received by another application.
Action (R,F)
This can be R to reject the incoming call, or F to forward
the incoming call. These conditions apply when no
application is listening for the routing list entry which is the
best match for the incoming call.
If this parameter is set to R (reject) and your application is
not running when you try to establish a call, the call will be
cleared with cause 0 and diagnostic 0. If it is set to F the
next best match is selected, and so on until an entry that
specifies R is selected and the call is rejected.
If a call does not match any entry in the routing table, it is cleared with cause 0,
diagnostic 0.
Chapter 4. Tools
85
4.4 Other X.25 Commands
The X.25 LPP offers a set of specific commands to manage X.25 configurations
on the RISC/6000. We present in this section only the purpose of each command.
More details on the syntax and the use of these commands are available in
Appendix A of the AIXLink/X.25 Version 1.1 for AIX: Guide and Reference manual.
Other commands include:
x25ip
The x25ip command updates or displays translation information in the
IP/X.25 translate table. The x25ip -h rouse -s command displays:
IP/X.25 Switched Virtual Circuit Configuration
IP host name
rouse
Remote DTE address
3106010762
Rcv packet size
Xmit packet size
Rcv window size
Xmit window size
Closed user group index
Closed user group index (outgoing)
RPOA selection
User-defined facilities
Call user data
cc
86
RS/0000 X.25 Cookbook
lsx25
The lsx25 command displays the configuration of the X.25 support on
the system:
****************************************************************
* Configuration report for X.25 LPP ports configured
*
****************************************************************
Machine: strider
****************************************************************
* Report by slot number - bus 0
****************************************************************
Slot 1 - empty
Slot 2 - empty
Slot 3 - empty
Slot 4, ampx0
X.25 Co-Processor/2 Adapter
Slot 4, twd0
X.25 Streams driver
Physical port 0 is x25 port sx25a0 •31060760“
Slot 5, tok0
Token-Ring High-Performance Adapter
Slot 6, gda0
Grayscale Graphics Display Adapter
Slot 7 - empty
Slot 8, scsi0
SCSI I/O Controller
****************************************************************
* Report by X.25 port′ s logical location
*
****************************************************************
X.25
Logical
Logical
Port
Driver
NUA
COMIO
TCP/IP
board
port
sx25a0
twd0
31060760 x25s0
xs0
0
0
****************************************************************
* Report by X.25 port′ s physical location
*
****************************************************************
X.25
Phys.
Port
Driver Adapter
Slot Port Interface
sx25a0
twd0
ampx0
4
0
cable selectable
****************************************************************
* Report by NUA
*
****************************************************************
NUA
X.25 Port
31060760
sx25a0
****************************************************************
* Report of COMIO emulators
*
****************************************************************
COMIO
X.25 Port
x25s0
sx25a0
****************************************************************
* Report of X.25 TCP/IP (xs) interfaces
*
****************************************************************
TCP/IP
addr
X.25 Port
xs0
10.2.0.1
sx25a0
x25status A new command, x25status, has been added to allow customers to
view the current status of their ports. It will display the current state
of the packet layer on all defined ports. The following is a list of
possible packet layer states:
Chapter 4. Tools
87
•
Disconnected
•
Restart in Progress
•
Registration in Progress
•
Line Cleanup in Progress
•
Packet Layer Connected
The packet layer states actually reflect the state of the link between
the DTE and DCE.
Each time a virtual circuit is established, the Active SVCs or Active
PVCs count is incremented depending on the type of virtual circuits
the port uses.
Link status for kili
Port
sx25a0
sx25a1
sx25a2
Packet State
PACKET LAYER CONNECTED
PACKET LAYER CONNECT
DISCONNECT
Active Active
SVCs
PVCs
1
0
In this example, sx25a0 has a link with the DCE and an established
virtual circuit. Sx25a1 has a link, but a virtual circuit has not been
established, and port sx25a2 is not active.
sx25debug This command is a debugging aid. It has two basic functions: to read
debug and error messages from the microcode and to display them to
stdout.
1. Use the -b flag to specify a logical board number. This number
can be attained by executing the lsx25 command.
2. When the -i flag is specified, this is interactive mode and allows
characters to be entered from the keyboard. In this mode the
microcode is polled to ensure it is operational. The response of
″pse_gdebug: Alive″ indicates all is OK.
You must have root authority in order to run this command.
88
mksx25
The mksx25 command initializes the attributes of the X.25 port
specified.
chsx25
The chsx25 command re-initializes the attributes of the X.25 port
specified.
rmsx25
The rmsx25 command removes an X.25 port.
mkpvc
The mkpvc command creates or modifies a non-default permanent
virtual circuit (PVC) on an X.25 port.
lspvc
The lspvc command displays the non-default permanent virtual circuit
(PVC) attribute information for an X.25 port.
RS/0000 X.25 Cookbook
4.5 Configuration Tools
The AIX X.25 LPPs include shell scripts to backup, remove and restore your X.25
configuration.
4.5.1 The backupx25 Script
This script is used to save the configuration of the X.25 LPP to a set of files.
Those files can be used later to reconfigure the system. The files contain
information to restore:
•
Adapter configuration
•
Device driver configuration
•
Port configuration
•
COMIO configuration
•
TCP/IP configuration
•
PAD profiles
The script is executed by entering:
/usr/bin/backupx25
Use the -d flag to specify the directory for the files. The default is the current
directory.
The -v option, for verbose mode, will display key messages during execution.
4.5.2 The restorex25 Script
This is a shell script to restore the configuration of the LPP from the backup files
created by the backupx25 script.
The script is executed by entering:
/usr/bin/restorex25
Use the -d flag to specify the directory for the files. The default is the current
directory.
The -v option, for verbose mode, will display key messages during execution.
4.5.3 The removex25 Script
This is the script to remove the configured instances related to the X.25 LPP.
The script is executed by entering:
/usr/bin/removex25
The flags for the script are:
-q
-v
-d
-f
assume ″yes″ to removal
verbose
directory of files from backupx25
remove even if no backup is found
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Chapter 5. Packet Assembler Disassembler (PAD)
In this chapter, we will present the PAD implementation in the AIX/6000 X.25
LPPs. For further information, see AIXLink/X.25 Version 1.1 for AIX: Guide and
Reference Manual .
5.1 Using a PAD
X.25 defines the relationship between a DTE node and a network′s DCE. The
CCITT also defines the attachment of asynchronous start-stop devices to the
PSDN in recommendations X.3, X.28 and X.29. (See 5.2.1, “X.3, X.28 and X.29
Standards” on page 93.) The asynchronous device is typically a low-cost
terminal such as an IBM 3151 or 3152. As these terminals lack the intelligence
of a full-function node on the network, they rely on a device called a Packet
Assembler Disassembler (PAD).
A PAD is a protocol converter interfacing asynchronous terminals with an X.25
network or an X.25 network with applications written for asynchronous terminals.
Low-cost asynchronous terminals are connected by the public switched
telephone network to a local public outgoing PAD, often simply referred to as a
PAD. The PAD takes the ASCII data stream coming from the terminal, buffers it,
converts it into a properly formatted X.25 packet and sends it over the X.25
PSDN, addressed to the desired DTE.
Data from the terminal that has been divided into packets and shipped by a PAD
to the DTE node must be received by some incoming PAD software (also
referred to as an X.29 interface). This incoming PAD unpacks the data and
passes it to the application (typically, the TTY driver) for processing, as if it were
coming from directly attached asynchronous terminals. The other way, data
coming from the application is first put into packets by the X.29 PAD and
transferred over the network. When the PAD receives a packet addressed to the
terminal, it reverses the process. This presents the data in the form that the
terminal can accept.
The computer industry has expanded the definition of PAD to include protocol
conversion between X.25 and various teleprocessing protocols. Some users talk
about SDLC PADs, BSC-3270 PADs and so on. Users must write programs to
support incoming packets from these PADs on AIX hosts.
 Copyright IBM Corp. 1996
91
Figure 28. The Various Types of PADs
5.2 Function of the PAD
Basic functions include:
92
•
Assembly of characters into packets (asynchronous-to-X.25)
•
Disassembly of the packet′s user data field (X.25-to-asynchronous)
•
Handling of virtual call setup, clearing, resetting and interrupt procedures
•
Generation of service signals
•
Forwarding packets when the proper conditions exist
•
Transmitting data characters, including start, stop and parity elements, as
appropriate to the start-stop terminal
•
Handling a break signal from the start-stop terminal
RS/0000 X.25 Cookbook
•
Editing of PAD command signals
•
Setting and reading the current value of PAD parameters
Optional functions include:
•
A mechanism for selection of a standard profile
•
A mechanism for automatic detection of data rate, code, parity and optional
characteristics
•
A mechanism for a remote DTE to request a virtual call between the
start-stop mode DTE and another DTE
5.2.1 X.3, X.28 and X.29 Standards
Figure 29. X.3, X.28 and X.29 Standards
The above figure illustrates the components and standards used to attach an
asynchrounus terminal to a remote host via X.25.
The asynchronous terminal DTE-C attaches to a packet assembler/disassembler
(PAD), the function of which is to handle the mapping of characters from the
terminal side into X.25 packets on the network side.
X.3 defines a set of parameters that the PAD uses to identify and control the
attached terminals. A complete set of parameters is called a profile, and each
DTE-C has its own profile selected or set for use with the PAD.
X.28 defines the control procedures used to establish the physical connection to
the PAD, the commands the user sends to the PAD and the service signals sent
by the PAD to the terminal user. Simply, X.28 defines how a terminal user can
control the X.3 PAD parameters. It specifies the command and response formats,
as well as status indicators.
X.29 defines the way in which a PAD and a remote DTE (or another PAD)
exchange control messages on an X.25 virtual circuit. The messages are
formatted as special X.25 packets called qualified data packets. For example, the
packet mode DTE may use an X.29 message to change one of the internal X.3
parameters in the PAD. X.29 messages will only be effective when an X.25 call is
established. The user at the terminal is not explicitly aware of the X.29
communication between the PAD and the remote DTE. The user at the terminal
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93
logs into the host DTE in the same way as the user of an ASCII terminal locally
attached to the same host.
5.2.2 Outgoing PADs
PADs used to establish connections from asynchronous devices are outgoing
PADs. These PADs can be provided by different sources and may be physical
devices or emulated by software.
5.2.2.1 Public PAD
A public PAD is a PAD provided by the Post Telegraph Telephone (PTT)
administration that you can access by a local call on the public switched
network. Once your terminal is connected to the public PAD, you enter the NUA
of your host DTE and the PAD will establish the communications.
5.2.2.2 Private PAD
A private PAD is a hardware device with several asynchronous connectors and
an X.25 attachment. This commercially available device can be connected to a
public or private X.25 PSDN and has the same capabilities as a public PAD.
5.2.2.3 Integrated PAD Software
Integrated PAD software is a software product emulating a PAD. You can install
it on a computer supporting an X.25 connection, (xspad does this function.) It
generally provides an asynchronous terminal emulator or can use existing ones
such as ATE or CU. With the X.25 LPP, the xspad function performs this role.
Integrated PADs are software emulations of private PADs.
Figure 30 compares a public PAD and an integrated private PAD.
Figure 30. Public PAD vs. Integrated Private PAD
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5.2.3 Incoming PADs
Private PADs are often reversible and may be used to provide X.25
communications capability between devices with only asynchronous
attachments.
Figure 31. Private PADs Used to Carry Asynchronous Connections over a PSDN
An incoming PAD can be implemented either as an X.29 daemon or as an X.29
device driver. The X.25 LPP software uses the X.29 daemon implementation and
STREAMS modules.
5.3 CCITT PAD Interfaces
The PAD performs a number of functions and exhibits operational
characteristics. Some of the functions allow the terminal, the X.25 host or both
to configure the PAD so that its operation is adapted to the terminal
characteristics and, if possible, to the application.
5.3.1 PAD Parameters
The operation of the PAD depends on the value of the set of internal variables
called PAD parameters. An independent set of parameters exists for each
start-stop mode DTE. The current value of each PAD parameter defines the
operational characteristic of its related function.
Normally, the values of the parameters are chosen by the selection of one of the
available profiles. Subsequent changes for a given terminal session are usually
done under the control of the session′s tty subsystem on the host PAD. When the
application being run requires a change to the terminal characteristics, it will
modify the session′s stty structure which will in turn cause the X.29 protocol to
issue a change to the session′s X.3 parameters held in the terminal PAD.
The PAD parameters are listed in F.1, “PAD Parameters” on page 287. They are
referenced as PAR 1 to PAR 22. Here are descriptions of some of the
parameters:
PAR 1 - PAD recall
This parameter specifies the character that a user can type at the
terminal to interrupt the data flow with the X.25 host in order to to
send commands to the PAD. This parameter operates like a break
key.
Possible values are:
0
1
Data flow may not be interrupted; the user may not enter
PAD commands.
The escape character is CTRL-P.
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95
32-126
Value of the PAD recall character in decimal.
Note: If this parameter value is changed to 0, the user will no longer
be able to change PAD parameters.
PAR 2 - echo
This parameter specifies whether characters received from the
terminal are to be transmitted back to the terminal.
Possible values are:
0
1
No echo by the PAD
Local echo provided by the PAD
When working in line mode, this parameter should be set to 1 to get
an echo from the PAD, and the echo provided by the host should be
disabled with the stty -echo command.
PAR 3 - data forwarding signal
This parameter specifies the characters that will cause the data in the
buffer to be forwarded over the network to the host, as defined in
X.25.
Possible values are:
0
1
2
4
8
16
32
64
Data forwarding not controlled by a character
Data forwarding controlled by alphanumeric characters (A-Z,
a-z, 0-9)
Data forwarding on receipt of CR
Data forwarding on receipt of ESC, BEL, ENQ, ACK
Data forwarding on receipt of DEL, CAN, DC2
Data forwarding on receipt of EXT, EOT
Data forwarding on receipt of HT, LF, VT, or FF.
Data forwarding on receipt of any character from columns 0 and
1 of the ASCII code page
If this parameter is set to 0, every character typed at the terminal is
sent by the PAD in an individual packet. For the other settings, the
PAD acts as a buffer and sends a packet only when the specified
character is entered. If the terminal is in line mode, for example
entering UNIX commands, this parameter may be set to 18. Thus,
packets will only be sent to the host on pressing Enter, Ctrl-c or
Ctrl-d.
PAR 4 - idle timer delay
This parameter specifies a timeout period for the reception of
characters from the terminal. After this timeout expires, characters
already received by the PAD are formatted into a packet and sent
across the X.25 network to the host.
Possible values are:
0
1-255
No timeout period is used
Timeout period expressed in units of 0.05 seconds
If using line mode, this parameter would be set to 0. When a
non-zero value is used, this parameter can improve the performance
of applications transferring data from the terminal to the host, as the
time delay between the PAD receiving two consecutive characters is
lower than the timeout period. The PAD would accumulate the data
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and only send it when it has a full packet or when the file transfer
application has stopped sending characters.
PAR 20 - echo mask
This parameter, used in conjunction with PAR 2, controls which
characters are echoed back to terminal, if local echo is enabled.
Possible values are:
0
1
2
4
8
16
32
64
128
All characters are echoed. There is no mask.
CR character is not echoed.
LF character is not echoed.
VT, HT, FF characters are not echoed.
BEL and BS characters are not echoed.
ESC and ENQ characters are not echoed.
ACK, NAK, STX, SOH, EOT, ETB, ETX characters are not echoed.
Editing characters designated by parameters 16-18 (described in
Appendix F, “PAD Parameters and Commands” on page 287)
are not echoed.
No echo of all other characters in columns 0 and 1, except
Delete or those characters mentioned above.
These parameters can be changed either from the terminal or by the
X.29 incoming PAD. The terminal user will use PAD commands (see
5.3.2, “PAD Commands”) to display or alter these parameters. The
parameters can be stored in a PAD profile, a set of predefined
parameter values stored in the PAD. The incoming PAD will use the
X.29 protocol to change the parameters of the outgoing PAD.
5.3.2 PAD Commands
When connected via an X.3/X.28 terminal PAD session, various commands can
be issued to the PAD. Some of these commands can only be issued after a
connection has been established with the remote X.25 host. Depending on the
PAD′s profile, the commands understood by the PAD are either based on the
CCITT standard, using parameter numbers, or interpreted in advanced mode,
using parameter names.
The start/stop mode DTE user may interact with the PAD using PAD commands .
These commands are provided for:
•
Establishing and clearing of virtual calls
•
Selecting PAD profiles
•
Displaying the PAD parameter values
•
Changing the PAD parameter values
•
Sending an interrupt or a reset packet
To enter a PAD command at the terminal, the user enters the command at the
PAD prompt. If the user is not connected to a remote host, the PAD prompt,
which is the asterisk character (*), will be displayed. To get the PAD prompt
when connected to a remote session, press Ctrl-p, the default character for PAR
1.
From the prompt, the following commands can be issued:
BREAK
Send a break character to the PAD.
Chapter 5. Packet Assembler Disassembler (PAD)
97
CALL
Establish a connection to the remote X.25 host, for example
call 3106010761.
CLEAR
Clear the connection with the remote X.25 host. The clear is
sent from the PAD immediately. (See the iclear command.)
HELP
Request help text. Each PAD command, parameter and
profile has help text associated with it, for example help
call.
To list the help topics, use help list. To change the
language of the help text, use the language command.
ICLEAR
Send an invitation to clear to the remote X.25 DTE. This
allows the remote host to send any pending data before
clearing the call.
INTERRUPT
Send an interrupt packet. The packet contents cannot be
user-specified.
LANGUAGE
Set the language for PAD help text to English, French or
Spanish, for example language french.
PAR
Display the PAD parameter values.
PAR?
Displays all parameters.
PAR? 2, 3 Displays parameters 2 and 3.
In advanced mode, read or parameter can be used instead of
par.
PROFILE
Display which profiles are available or change the profile.
Enter profile followed by the profile number, such as
profile51.
READ
See par.
RPAR/RREAD
Read the remote PAD parameters in implementations where
a remote PAD DTE is supported.
RSET/RSETREAD
Set the remote PAD parameters in implementations where a
remote PAD DTE is supported.
SET
Sets one or more of the PAD parameters:
set 2:1, 14:2
In advanced mode
set echo:1, lfpad:2
Note: The default profile does not allow the parameters to
be changed locally, as they are being controlled remotely
through the TTY subsystem and the stty command. Xspad
does not require the use of the set command or any of the
remote PAD commands ( rread, rpar, rset and restread).
STATUS
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Indicate whether a connection to the remote X.25 host is
active. Returns ENGAGED if it is active or FREE if the connection
has not been established.
5.3.2.1 Establishing Connections
To establish a connection with a remote X.25 host, a call must be made to it.
This call must contain the remote DTE′s address and any call user data or
facilities being requested.
Table 8. X.28 Facility Codes
Facility
code
Function requested
Value
(text that follows the facility
code)
C
Charging information
D
Call User Data
ASCII CUD string to be
added to the standard PAD
call CUD. Must be the last
part of the command string
E
Called Address Extension
Extended address
F
Fast select with no restriction
G
Closed User Group
CUG number
N
Network User Identification
NUI string
Q
Fast select with restrictions on response
R
Reverse charging
-
Facility end marker
End of facilities marker, to
then allow CUD
Calls can be placed from the command line, using xspad -a, or from the PAD
prompt. For example:
To establish a call to NUA 3106010761:
call 3106010761
To also request fast select and reverse charging:
call 3106010761 F, RTo also have ASCII base CUD user1:
call 3106010761 F, R- D user1
After a call has been made and accepted by the remote host, a connection has
been established. The terminal is now under the control of the tty subsystem of
the remote host. Typically, a login panel will be presented, and after the user
has logged in, it can be used in the same way as other attached ttys.
5.3.2.2 Terminating Connections
If for some reason the call establishment is rejected by the network or the
remote host, a clear packet will be received with a message similar to:
CLEAR DTE 0 241 - Call cleared, by remote device, data may be lost
This type of message will also be received on termination of the login shell used
to log in to the remote X.25 host. In these cases, the session was terminated
above the PAD layer and was unexpected, so the PAD could not determine if the
Chapter 5. Packet Assembler Disassembler (PAD)
99
termination was user initiated. If it had been user initiated, no data would have
been lost.
Another way for a user to initiate a clear is to use the iclear command from the
PAD prompt. Iclear causes the local terminal PAD to send a request to the host
PAD to clear the connection. The host PAD would then issue a clear but would
disregard any applications that might be running under this login. As the host
PAD software issued the clear, the diagnostics would reflect it as being an
expected clear and result in a message similar to:
CLEAR PAD 0 0 - Call cleared, remote request
In this example, the additional text shown is given only when advanced mode is
enabled through the profile; otherwise, only the base clearing reason is given.
5.3.2.3 Clearing Codes
When a call is cleared, the information passed in the X.25 packet is displayed. If
advanced mode has been selected, a more-detailed explanation of the clear is
given.
Table 9. Clearing Codes
Code
Explanation
OCC
Remote DTE busy
NC
Network congestion
INV
Invalid facility
NA
Access barred
ERR
Local procedure error
RPE
Remote procedure error
NP
Number not assigned
DER
DTE out of order
PAD
DTE clearing
DTE
DTE device clearing
RNA
Reverse charging rejected
ID
Incompatible destination
SA
Ship cannot be contacted
FNA
Fast select rejected
ROO
Cannot route as requested
Appendix F, “PAD Parameters and Commands” on page 287 lists these
commands.
5.3.3 PAD Profiles
A PAD profile is a predefined set of PAD parameters. The terminal PAD in the
X.25 LPP implements four standard, predefined profiles:
100
50
Standard profile with minimum textual information
51
Standard profile with extended textual information
RS/0000 X.25 Cookbook
90
CCITT simple profile
91
CCITT transparent profile
AIXLink/X25 provides three other predefined profiles.
10
Default for incoming PAD
20
Default for outgoing PAD
30
Default for PAD printing
91
CCITT transparent profile
Table 10. Parameter Settings for Predefined PAD Profiles
PAR
50
51
90
91
1
1
1
1
0
2
1
1
1
0
3
2
2
126
0
4
0
0
0
20
5
0
0
1
0
6
5
16
1
0
7
21
21
2
2
8
0
0
0
0
9
0
0
0
0
10
0
0
0
0
11
14
14
14
14
12
1
1
1
0
13
5
5
0
0
14
0
0
0
0
15
1
1
0
0
16
8
8
127
127
17
3
3
24
24
18
18
18
18
18
19
2
2
1
1
20
64
64
0
0
21
0
0
0
0
22
0
0
0
0
A particular profile can be selected using the prof PAD command. To list the
available profiles, use the help prof command. For AIXLink X.25 V1.1.3, the
default profile is in /etc/sx25pad/x28parm and can be seen as profile #20,
currently named titn_test.
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101
Table 11. Parameter Settings for Default PAD Profiles
PAR
10
20
30
1
1
1
0
2
0
1
0
3
0
2
126
4
1
0
1
5
0
0
2
6
16
16
0
7
4
21
2
8
0
0
0
9
0
0
0
10
0
0
0
11
n/a
14
n/a
12
0
1
1
13
0
5
0
14
0
0
0
15
0
1
0
16
8
8
127
17
24
3
24
18
18
18
18
19
2
2
1
20
64
64
0
21
0
0
0
22
0
0
0
If your system is used as an integrated PAD, profiles can be defined to set the
PAD parameters to commonly used values. These profiles can be used to set
PAD parameters for outgoing calls or those of a remote PAD receiving incoming
calls.
The profiles are stored as an ASCII file, /etc/sx25pad/x28parm, that can be
modified with a text editor.
5.4 Configuring the PAD
Once the PAD software is enabled on the system, it can be used as an outgoing
terminal PAD, supporting local terminal users, or as an incoming host PAD,
working with remote terminal PADs. Both modes of operation can be run at the
same time.
For use as a terminal PAD, each terminal or terminal emulator that requires a
PAD session would execute the xspad command. Xspad connects the terminal to
an application that provides the standard X.28 interface. See 5.6, “PAD Usage”
on page 112 for more details on the use of terminal PAD sessions.
When the system is to be used as a host PAD, then no user interaction takes
place on the system itself. Once the system isconfigured to enable the PAD,
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users can connect from terminals connected to remote terminal PADs. The
system running the host PAD will allow login and applications as for any other
type of remote ASCII terminal.
5.4.1 PAD for AIXLink/X.25 1.1.2 Running on AIX V.4
There are three basic PAD features that are controlled by four PAD configuration
files located in the /etc/sx25pad directory. These configuration files allow
changes to be made to the environment for incoming PAD calls only.
•
Automatic login of incoming calls based on calling address
•
Automatic selection of TTY and PAD parameters for incoming calls per
calling address and userid
•
Restriction of outgoing calls to specific addresses based on calling user
The x29d daemon must be running for these features to work. The daemon can
be started with flags to allow the use of these features. The four PAD
configuration files are:
tty
This file defines the tty attributes. The default tty attributes are in the
″cooked″ mode (for example, local echo, editing, etc..)
profile
This specifies the PAD profile to be used. The default profile is shown
in Table 11 on page 102.
address
Selects features based on address. The default uses the ″cooked″ tty
mode and the ″default″ profile.
user
Selects features as per the user name. The default uses the ″cooked″
tty mode, the ″default″ profile and all outgoing calls for all users.
5.4.1.1 Automatic Login
The automatic login feature can be implemented by defining the login_user
attribute in the address file with an existing user name. When a call is received
from an authorized address, the call is automatically logged in as that user. The
normal system authentication screen/method is NOT invoked.
If the attribute in the address file reads:
31*:
login_user = user1
This causes any call from a NUA starting 31* to be automatically logged into the
machine as user1.
5.4.1.2 Automatic TTY and PAD Parameter Selection
The tty and profile files can be used to define sets of parameters by name.
These are then pointed to by the in_tty and in_profile attributes in either the
user or address files. This allows the selection of any combination of host tty
and remote PAD parameters based on calling address, user or both. Since these
attributes can appear in either of the files, it is necessary that one file should
have priority over the other, should the attributes be set in both files. By default,
the user files attributes take priority unless the default prioritization is overriden
by the setting on the attribute stanza.
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103
attribute = value;priority
If the in_tty attribute is set in both the user and address files as shown below
but the address file has the priority set, then the tty attributes are set to the
values defined by tty2 as specified in the address profile for the particular user.
user file
user1:
in_tty = tty1
address file
addr1:
login_user = user1
in_tty = tty2;0
5.4.1.3 Restriction of Outgoing Calls
The out_allow and out_deny attributes can be defined in the user file to control
which addresses a user can place PAD calls to. The values of this attribute can
consist of patterns so that complex sets of addresses can be specified to tailor
the outgoing calls. For an outgoing call to succeed it MUST match the out_allow
attribute and MUST NOT match the out_deny attribute. By default the out_allow
attribute is set to the asterisk character, which allows all users without explicit
entries in the user file to place outgoing calls to any address.
user1:
out_allow = 31*
out_deny = 31(3-5)*
User1 in the above example can call any address starting with 31, with the
exception of addresses starting with 313, 314 and 315.
5.4.2 PAD for AIXLink/X.25 1.1.3 (and later) on AIX V.4
The number of configuration files for this version of the AIXLink/X.25 product has
increased to allow greater tailoring to take place. The files are:
x28parm
x29parm
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This file defines the profiles and its values for the PAD outgoing
module. It also contains the standard values of 50, 51, 90 and 91. The
three new values given are:
•
10 (default); this is really only for X.29 calls and appears also in
the x29parm file
•
20 (titn_test), same as ″51″ and is the outgoing PAD xspad default
•
30 (print)
This file defines the profiles and values for the PAD incoming module.
The values for the five preset profiles are:
•
90 (CCITT Standard Simple Profile)
•
91 (CCITT Standard Transparent Profile)
•
10 (Default Profile)
•
20 (AIX/TITN Extended Compatibility Profile)
•
30 (Remote Printing Profile)
x29tty
This file defines the profile and its attributes for the PAD incoming.
The default for this is ″cooked″ mode. For PAD printing, ″raw″ mode
should be used.
x28user
This file selects the values for an outgoing user; the default is the #20
(51) profile and allows all calling addresses.
x29user
Selects the values for an incoming user; the default is ″cooked″ tty
mode and the default (#10) profile.
x29access This files selects key features based on the address. The default uses
the ″cooked″ tty mode and the default profile.
qdata
Defines the values needed for locally initiated PAD printing.
5.4.3 Default Initial Application
This allows an AIX host user, connected via X.25 and X.29, to select the initial
application which is presented. The criteria that must be met are configurable
and based on the X.25 calling address. This is not configurable by any user but
is configured for each by a highly privileged AIX user, such as root. There are
three kinds of initial applications that can be started upon acceptance of the
incoming X.25 call using the X.29 protocol ID. They are logged user, trusted user
and selective user.
5.4.3.1 Logged User
For a logged user, an AIX login is done in the normal way and conventional
password validation and security processing are performed by the user. There
can be multiple ″logged users″ per X.25 calling address. This kind of initial
application processing is based on the fact that the X25 calling address is not
configured in the x29access file -- or that the address is configured but the
access criteria are not satisfied. A ″logged″ user invokes ″login″ ONLY as the
default if nothing is specified or if a field value is incorrect or NOT satisfied. A
″logged user″ who supplies an AIX login has a non-default initial tty-X.29/X.3
profile which is set under two conditions:
•
The user has an X.25 address in the x29access file and the attributes for that
address reference a valid tty-X.29/X.3 profile set.
•
The user′s X.25 address is in the x29user file and the attributes for that
address reference a valid tty-X.29/X.3 profile set.
5.4.3.2 Trusted User
A trusted user is when an AIX login is done so that it circumvents the usual
userid and password validation. This is restricted to one login ID per X.25 calling
address. This processing is started when the X.25 calling address is configured
in the x29access file. The userid specified as the trusted user must be a valid
AIX user with a valid password. The initial application is AIX ″login″ which
executes without performing standard authentication including password
authentication.
NOTE: The x29d daemon must be restarted to ensure that the x29access file is
re-read when any changes have been made to the file.
Chapter 5. Packet Assembler Disassembler (PAD)
105
5.4.3.3 Selective User
A ″selective user″ starts an application preconfigured in the x29access file. The
application is responsible for the security arrangements. Additional criteria
linked to the X.25 calling address may need to be satisfied before the initial
application is started and the ″selective user″ actually exists.
A ″selective user″ must satisfy the criteria as specified by the access_class
value: remote, user_data, sub_address or user_sub_address values. Look at the
section below for more about the specific criteria. The ″selective user″ will cause
the initiation of the application as specified with the initial_application field
(instead of the default of login). This application will be executed as the user
specified by the login_id field.
5.4.3.4 access_class values
For each X.25 calling address in the x29access file there is an access_class
attribute that specifies one of the following values:
LOGGED
Connections from the corresponding address undergo standard
authentication (the criteria set to be satisfied) before AIX host access
is granted. The initial application is AIX ″login″, which performs the
authentication. Typically, a shell is spawned if authentication
succeeds. (The call initiator is known as a ″logged″ user).
TRUSTED Connections from the corresponding address are not authenticated
(no additional criteria need to be satisfied) before AIX host access is
granted. However, the initial application is AIX ″login″, which executes
without performing standard authentication including password
authentication. In other words, the user name specified in the
login_id keyword is logged in automatically.
REMOTE
Connections from the corresponding address are granted AIX host
access without satisfying additional criteria. (The call initiator is
known as a ″selective″ user). The initial application must be specified
by the initial_application attribute and the login_id specified must
be that of a valid AIX user with a valid AIX password.
SUB_ADDRESS Connections from the corresponding address are granted AIX
host access only if the sub-address of the X.25 call packet called
address matches that in the sub_address attribute. The match MUST
be exact. (The call initiator is known as a ″selective″ user). The initial
application must be specified by the initial_application attribute,
and the login_id specified must be that of a valid AIX user with a
valid AIX password.
USER_DATA Connections from the corresponding address are granted AIX host
access only if a user data segment from the X.25 call packet matches
that specified by the user_data attribute. The matching conditions are
specified in the user_data attribute description. (The call initiator is
known as a ″selective″ user). The initial application must be specified
by the initial_application attribute, and the login_id specified must
be that of a valid AIX user with a valid AIX password.
USER_SUB_ADDRESS Connections from the corresponding address are granted
AIX host access only if both the criteria specified in the sub_address
and user_data attribute descriptions are satisfied. (The call initiator is
known as a ″selective″ user). The initial application must be specified
by the initial_application attribute, and the login_id specified must
be that of a valid AIX user with a valid AIX password.
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The following three attributes were added after AIXLink/X.25 Version 1.1.3 was
released and are available via a PTF upgrade. Please contact your local AIX
Systems Support Centre for the PTF. At the time of updating this redbook, the
PTF was U443807.
TRUSTED_USER_DATA Connections from the corresponding address are granted
AIX host access via the login_id specified only if a user data segment
from the X.25 call packet matches that specified by the user_data
attribute. (The matching conditions are specified in the user_data
attribute description.) No authentication (additional criteria) needs to
be satisfied before AIX host access is granted. The initial application,
AIX ″login″, executes without performing standard authentication,
including password authentication. Whatever is set up as the user′ s
initial program is spawned by login. (The call initiator is known as a
″trusted″ user with special criteria needing to be satisfied.)
TRUSTED_SUB_ADDRESS Connections from the corresponding address are
granted AIX host access via the login_id specified only if the
sub_address of the X.25 call packet called address matches that in the
sub_address attribute. The match must be exact. No authentication
(additional criteria) needs to be satisfied before AIX host access is
granted. The initial application -- which executes without performing
standard authentication, including password authentication -- is
spawned by login. (The call initiator is known as a ″trusted″ user with
special criteria needing to be satisfied.)
TRUSTED_USER_SUB Connections from the corresponding address are granted
AIX host access via the login_id specified only if both the criteria
specified in the sub_address and user_data type are satisfied
( user_data and sub_address). No authentication (additional criteria)
needs to be satisfied before AIX host access is granted. The initial
application is AIX ″login″, which executes without performing standard
authentication, including password authentication. (The call initiator
is known as a ″trusted″ user with special criteria needing to be
satisfied.)
5.4.4 Selectable Profile
The selectable profile mechanism allows for the selection of non-default profiles
for PAD users. For outgoing PAD application connections, the new functionality
allows non-default X.28/X.3 parameter profiles to be selected by name or
number. For incoming connections, both non-default X.29/X.3 profiles and tty
parameter profiles can be selected. The tty-X.29/X.3 profile sets are selected
based on the configuration data found in the x29access and x29user files.
5.4.4.1 Incoming X.29/X.25 Connection Profile Selection
The method of selecting non-default tty-X.29/3 profile sets is based on the setting
of the x3_profile field value name and tty_profile field value name. There are
several ways these profiles are selected depending on how the data is
configured in the x29access and x29user files and the user′s AIX login. In all
cases, a member-type profile must be referenced in order to select a non-default
profile set. The x29parm file contains the members of the X.29/X.3
parameter-type. The x29tty file contains the members of the tty
characteristic-type. Together, these types compose the profile sets.
Chapter 5. Packet Assembler Disassembler (PAD)
107
5.4.4.2 Outgoing X.28/X.25 Profile Selection
The PAD application can select a non-default initial X.28/X.25 profile in three
ways:
•
Using the xspad -p profile, where profile is a selected name or a defined
numeric profile number, (#20).
•
Preconfiguring a non-default profile in the x28user file. It is prerequisite that
the file contain a data set for the user′s AIX login. Then, the x3_profile field
can be used to specify a profile.
•
Using the standard profile command, (PROF).
The available profiles are all stored in the x28parm file.
5.4.4.3 Distribution of Profile Data
All of the X.28/X.3 parameter profiles are stored in the x28parm file. However
the xspad command does not directly extract profiles from the x28parm file.
Before any profile selection occurs ,the X.28 STREAMs module is pushed on
X.25. It is at this time that the x28parm file is downloaded in the STREAMs
module. This is because a new non-initial profile can be selected at a later stage
of xspad execution.
5.4.5 Configurable Profile
The x28parm file contains all the X.3 parameter profiles and is used to tailor the
characteristics of the outgoing X.28/X.25 PAD sessions. The x29parm file also
contains X.3 parameter profiles and along with the x29tty file, which contains tty
charactistic profiles, is used to tailor the characteristics of the incoming X.29/X.25
sessions.
Both the x28parm and x29parm files have the same format. Each profile contains
all 22 standard CCITT X.3 parameters along with descriptive information. Each
profile has a unique name and numerical identifier, and all the fields must be
present even if they are NOT used. The fields can be in any order, but it is
recommended that they are kept in ascending numerical order. There is one
value that is not used: That is the x3_11_dte_speed parameter, which is read only
and ignored.
Each profile in the x29tty file has a unique name. The field names are similar to
those used in the normal AIX tty structures. It is easy to set the tty
characteristics as almost all of them are either enabled or disabled by setting
the field to either on or off. All the fields must be present and in the correct
order.
5.4.6 Security Features
Security for outgoing X.28/X.25 PAD sessions is on a per-user basis. This is
achieved by restricting the X.25 addresses to which a particular user can
connect.
Security for incoming X.29/X.25 sessions depends on the user′s X.29 access
category:
logged user
Uses the normal AIX login security, (user must type in user name and
password).
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RS/0000 X.25 Cookbook
trusted user
Controlled by the X.25 calling address and data in the x29access file.
The implementation changes DO NOT change the security method.
selective user
Controlled by entries in the x29access file.
5.5 PAD printing
To allow PAD printing, you must have the following filesets installed.
•
printers.rte
•
printers.rte.(printer type being used)
•
printers.hpJetDirect.attach
The printers.hpJetDirect.attach package is important in that the AIXLink/X.25 LPP
does not create its own pioin and pioout applications; it uses the standard ones
which come with this package. With the exception of AIXLink/X.25, the other
packages mentioned are shipped as part of the BOS fileset.
PAD printing can be accomplished by one of two methods. Both methods require
an X.25/X.29 connection between the AIX host and the PAD to which the printer
is attached:
Remote initiated
The remote PAD printer can poll (initiate the CALL) the AIX host for
print jobs queued for it.
Host/Locally initiated
The AIX host can automatically transmit queued jobs (initiate the
CALL) to the PAD printer. This method can only be used if the PAD
printer has a unique NUA and if the VC has been established between
the PAD and the AIX host. This setup should be done in a manner
that will not interfere with other devices attached to the PAD.
To enable PAD printing using either method, the AIX host needs substantial
configuration and software modules to be installed (as mentioned above). There
are two categories of configuration data. The first describes printer attributes,
and the second associates NUAs and AIX print queues with actual printers.
The software functionality specific to the host-initiated method is the
establishment of an X.25/X.29 connection.
For the remote-initiated method, it is as follows:
•
Acceptance of an incoming X.25/X.29 connection
•
Association of a destination NUA subaddress with a print queue
•
Configuration of X.3 parameters
•
Activation of the queue
The software functionality for both PAD printing methods:
•
Obtaining jobs from the front of a print queue
•
Obtaining ″control″ of an X.25/X.29 remote printer connection
•
Transmission of a job at a rate that does not overrun the printer
Chapter 5. Packet Assembler Disassembler (PAD)
109
•
Releasing a X.25/X.29 connection when piobe stops passing jobs
5.5.1 Setting up the PAD Printer Queue
The printer queue for PAD printing is set up in exactly the same way as for
normal AIX printing:
•
Define the printer device after IPL as ″Print Spooling″.
•
Define a print queue. (This MUST be hpJetDirect - Network printer.)
•
Select the printer type.
Once these are configured, you need to enter the queue name and the hostname
associated with the printer. This will create an entry in /etc/qconfig with the print
queue name that has been chosen. The remaining configuration is dependent
on whether you choose to use remotely or locally initiated printing.
5.5.2 PAD Printing Process
PAD printers are defined as AIX print queues and are available to all AIX users.
There are two processes which interact with the printer qdaemon to accomplish
PAD printing. They are:
•
piox25
•
piox25start
Piox25 is started indirectly each time PAD printing is invoked and the qdaemon
removes a job from the print queue. The job is piped from piobe to piox25, which
transmits it to the network through the X.25 connection. Pacing and formatting
are handled by piobe, hence the need for the printers.hpJetDirect.attach fileset to
be installed.
5.5.3 Configuration for Remotely Initiated Printing
The X.25 calling address of the printer needs to be configured as follows in
/etc/sx25pad/x29access:
1. The access_class must be set to one the selective types:
•
REMOTE
•
SUB_ADDRESS
•
USER_DATA
•
USER_SUB_ADDRESS
The user_data, sub_address specified or user_sub_address must have the
criteria satisfied via the appropriate fields.
2. The initial_application paramater must be set to /usr/lpd/piox25start
QNAME, where QNAME is the name of the print queue associated with the
remote printer.
3. The login_id parameter must be set to a valid AIX user. (This user MUST
have a password set up.)
4. The tty_profile parameter should be set to raw, and the x3_profile should
be set to an X.3/X.29 profile consistant with remote printing. Currently, one
is available in the x29parm file as number 30 or the name ″print″.
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5. The /etc/qconfig file entry for the queue must have the backend field so that
it points to /usr/sbin/piox25remote.
pad_q:
[email protected]
[email protected]:
file=/var/spool/lpd/pio/@local/dev/[email protected]#hpJetDirect
header=never
trailer=never
access=both
backend=/usr/sbin/piox25remote pad_q
Where kili = hostname
pad_q = print queue name
When x29d receives an X.25/X.29 call from the specified calling address
indicating the criteria were satisfied, it spawns piox25start. The piox25start
process does two things: It activates the specified print queue using the enq
command, and it indicates the name of the device over which the X.28/X.29
connection is established.
5.5.4 Configuration of Locally Initiated Printing
To configure locally initiated printing do the following:
1. In the /etc/xs25pad/qdata file ,add QNAME LDEVICE DEST.
Where QNAME is a print queue name; LDEVICE is a logical device name,
such as sx25a#; and DEST is the X.25 called address of the hardware PAD to
which the local printer is connected. (This would also include the subaddress
if set up as such.)
2. In the /etc/qconfig file, the backend field in the configuration must be
/usr/sbin/piox25local.
pad_q:
[email protected]
[email protected]:
file=/var/spool/lpd/pio/@local/dev/[email protected]#hpJetDirect
header=never
trailer=never
access=both
backend=/usr/sbin/piox25local pad_q
Where fili = hostname
pad_q = print queue name
3. You will need to preconfigure the X.3 parameters for the remote hardware
PAD. Features such as parity checking and generation need to be disabled,
and ancillary device control needs to be set for the type of printer.
Chapter 5. Packet Assembler Disassembler (PAD)
111
5.6 PAD Usage
This section covers how to start an X.28/X.3 terminal PAD session. For
information on how to start X.29 on the system, refer to 5.7, “Incoming PAD
Setup.”
To start a terminal PAD session, run the xspad command. On systems where the
PAD is configured, this will start a terminal PAD session and provide the PAD
prompt (*). At the prompt, the PAD commands can then be used. For information
on how to start a terminal PAD session, refer to 5.8, “Setup of an Integrated
PAD” on page 114.
A typical PAD session would consist of the following steps:
•
Ensure the PAD is configured on the system
•
Start the terminal PAD session on an X.25 port:
xspad -l <port>
•
At the PAD prompt, issue the call to the remote X.25 host:
call <NUA>
•
Log on to the X.25 host and run the desired application
•
Exit off host
•
Press Ctrl-K to exit out of the xspad command
To avoid any interaction by the user (or to limit the interaction), the invocation of
the xspad command could be as such:
xspad -l <port> -a <DEST_NUA> (, <SRC_NUA>) -x
where <DEST_NUA> is the NUA being called and <SRC_NUA>, which is optional, is the
calling AIX address. The -x option will terminate the xspad command once
exiting from the host.
5.7 Incoming PAD Setup
To allow the RISC System/6000 to accept incoming calls from remote PADs, the
only thing that needs to be done is to ensure that the X.25 port has been
configured and that the X.29 daemon is running on the system. You do not have
to set up routing tables; this is all handled by the X.25 LPP device driver.
5.7.1 Listing the Configured Ports
This can be performed through SMIT as follows:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/Adapt
→
Manage X.25 LPP Device Driver
→
Manage X.25 Ports
→
List All Defined Ports
Or use the fastpath: smit cx25str_mp.
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5.7.2 Stopping the X.29 Daemon
This can be performed through SMIT as follows:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/Adapt
→
Manage X.25 LPP Device Driver
→
Manage the X.25 Triple-X PAD
→
Stop the Triple-X PAD X.29 Daemon
Or use the fastpath: smit x25str_pad
The name of the X.29 daemon is x29d.
5.7.3 Starting the X.29 Daemon
The X.29 daemon (incoming PAD) is the software that handles the incoming calls
from PADs and interfaces with tty-based applications. The X.29 daemon must be
running before a remote caller can access the system.
The X.29 daemon is started, by default, by the /usr/lib/drivers/pse/x29 entry in
the /etc/rc.net.x25 file. If this entry includes the -n option, incoming PAD calls
will not be allowed. This entry may be modified or deleted to determine if and
how the PAD daemon is automatically started.
Verify that this command is invoked correctly. If the daemon has been started
with the -n option, the daemon must be stopped and restarted to allow incoming
PAD calls. See 5.7.2, “Stopping the X.29 Daemon” to stop the daemon.
The daemon can be started at the command line (via the root user) by invoking
the following command:
/usr/lib/drivers/pse/x29d
This can be performed through SMIT as follows:
Devices
→
Communications
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Adapter
→
Manage Device Drivers for X.25 Co-Processor/2 or Multiport/Adapt
→
Manage X.25 LPP Device Driver
→
Manage the X.25 Triple-X PAD
→
Start the Triple-X PAD X.29 Daemon
Or use the fastpath: smit x25str_pad.
The name of the X.29 daemon is x29d.
There have been some additional flags added to the x29d which allow greater
flexibility in the usage of the daemon. The default x29d mode can run as an
outgoing PAD call validation daemon and an X.29 listener daemon.
Chapter 5. Packet Assembler Disassembler (PAD)
113
If the daemon is started using the -nflag, the daemon will only allow outgoing
PAD calls; all incoming calls will be ignored.
If problems are experienced with incoming calls being ignored, verify that the -n
option was specified. Stop and restart the x29d daemon.
5.7.3.1 User-Invoked x29d Options
The following options are passed to the x29d daemon after the daemon has been
started. They must be issued by a user who has logged into the AIX system via
the PAD.
Issuing the x29d command with the - a or - p options will not start the x29d
daemon.
-p user
This sets the initial tty and X.3 attributes of an X.29 session by AIX
user ID. This flag cannot be used with the -n flag. This requires that
x29d is already running as the X.29 listener daemon. Once set, the
only way to turn this option off is to reload the x29 daemon.
-a
This is an informational command to x29d. It outputs the calling X.25
address of the system initiating the X.29 session to stdout. X29d runs
and obtains the X.25 address; an AIX userid is not required as NO X.3
or tty attributes are related. This flag cannot be used with the -n flag
and needs the x29d to be already running as a listener daemon.
5.8 Setup of an Integrated PAD
The PAD function is implemented in the X.25 LPP. The xspad command provides:
1. The X.3 PAD emulation, allowing commands to be entered to make or clear a
call to a remote incoming PAD system
2. The emulation of an asynchronous terminal connected to the PAD through a
virtual tty
5.8.1 Starting the PAD Program
The xspad program can be started as follows:
xspad -l <port>
Once the PAD prompt ( *) is received, you can proceed with the connection as
described in 5.3.2.1, “Establishing Connections” on page 99.
An example of the screen format is as follows:
# ./xspad -l sx25a0
TWICE(r) X.3/X.28, (c)Copyright TITN Inc, 1984-1991, All Rights Reserved
*
From here, you would use the PAD commands as described in 5.3.2.1,
“Establishing Connections” on page 99 to proceed.
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5.8.2 Exiting
From the PAD command prompt, enter Ctrl-K to terminate the xspad program.
The xspad application must not have a call established when attempting to
terminate xspad.
5.9 X.25 PAD and C-Kermit
C-Kermit is freely available communication software used to transfer files. The
AIX X.25 PAD does not provide file transfer capability. This leads to C-Kermit
being used for file transfer. The AIX system can be the client, server or both.
IBM neither supplies nor supports C-Kermit.
5.9.1 Requirements
Since the programs are not IBM-supplied and the local or remote system may
not be an AIX system, the requirements are rather vague.
Local and remote hosts require a version of C-Kermit that supports the current
X.25 implementation. This is significant since AIXLink/X.25 for AIX Version 4.1
requires a different version of C-Kermit than the AIX X.25 LPP for AIX Version
3.2.5.
C-Kermit is normally distributed in source format. The program must be
compiled, renamed kermit and placed in a directory named in the path variable.
X.25 PAD must be properly configured.
For AIX X.25 to be a C-Kermit client, TCP/IP must be started.
5.9.2 Documentation
C-Kermit documentation is supplied with the source code.
5.9.3 AIX X.25 PAD as a C-Kermit Client
The AIX X.25 PAD does not provide the pty functions that C-Kermit requires.
C-Kermit has to be started on the local machine using the following command:
kermit -j local_host_name
Where local_host_name is the local TCP/IP host name.
At the C-Kermit prompt, configure the C-Kermit environment using the following
commands:
set buffers 300000 30000
set windows 31
set receive packet-length 9000
set send packet-length 9000
set filetype binary
connect
These commands may be stored in the .kermrc file.
Log on to the local host again. Start X.25 PAD and connect to the C-Kermit X.25
PAD server using the following commands:
Chapter 5. Packet Assembler Disassembler (PAD)
115
$ xspad <port_name>
* call <NUA>
Once connected to a remote host, start C-Kermit using the following command:
kermit -ix
Enter the C-Kermit escape character to access the C-Kermit menu and select the
option for command mode. These will be defined in the C-Kermit documentation.
At the C-Kermit prompt, enter the command to send or receive files:
send <local_file_name> <remote_file_name>
receive <remote_file_name> <local_file_name>
5.9.4 AIX X.25 PAD as a C-Kermit Server
Connect to the AIX system using X.25 PAD and start C-Kermit using the following
command:
kermit -ix
Enter the C-Kermit escape character to access the C-Kermit menu, and select
the option for command mode. These will be defined in the C-Kermit
documentation. At the C-Kermit prompt, enter the command to send or receive
files:
send <local_file_name> <remote_file_name>
receive <remote_file_name> <local_file_name>
5.9.5 Session Statistics
After file transfer, the user may enter stat at the C-Kermit prompt to display
session statistics for the most recent file transfer.
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Chapter 6. APIs: COMIO, NPI and DLPI
This chapter presents the APIs available in the X.25 LPP. These APIs can be
used to write applications tailored to specific needs. Since the new APIs, NPI
and DLPI now available with the LPP are based on the STREAMS environment,
first we will review the STREAMS concepts and mechanisms. Then, we describe
the NPI, DLPI and COMIO APIs. NPI stands for Network Provider Interface, DLPI
stands for Data Link Provider Interface and COMIO stands for Common
Input/Output, which is an emulation of the previously device driver interface
supported in AIX V3.
6.1 Implementation of X.25 in the STREAMS Environment
Figure 32 details the X.25 implementation in the STREAMS environment of the
RS/6000. This figure shows where each kind of application (NPI, DLPI and
COMIO) is interfaced.
Figure 32. X.25 In the STREAMS Environment
 Copyright IBM Corp. 1996
117
6.2 STREAMS
STREAMS defines standard interfaces for character input/output within the
system kernel and between the kernel and the rest of the system.
6.2.1 STREAMS Definition
STREAMS is a collection of system calls, kernel resources and kernel utility
routines for developing system communication services. STREAMS is used by
developers to provide services ranging from complete networking protocol suites
to individual device drivers.
The tools that compose the STREAMS environment allow you to create, use and
dismantle a stream. A stream is a full-duplex processing and data transfer path
between a driver in kernel space and a process in user space.
6.2.2 STREAMS Components
As shown in Figure 33, a stream is made of three main components:
Figure 33. Components of a Stream
Stream Head
Provides the interface between the stream and user processes. Its
principal function is to process STREAMS-related system calls.
Module
Processes data that travels between the stream header and the
driver. Modules may be optional when the driver performs all the
work needed.
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Stream End
Provides the services of an external input/output device or an internal
software driver. The internal software driver is commonly called a
pseudo device driver.
Using the tools, STREAMS passes data between a driver and the stream head in
the form of messages. Messages that are passed from the stream head toward
the driver are said to travel downstream while messages passed in the other
direction travel upstream .
6.2.2.1 Stream Head
The stream head provides the interface between an application program and the
stream for the transfer of data between the data space of a user process and
STREAMS kernel data space. Data sent to a driver from a user process is
packaged into STREAMS messages and transmitted downstream. Downstream
messages arriving at the stream head are processed, and the data is copied
from user buffers. These messages contains data, status and control information,
or a combination of both. Each message includes a specified message type
indicator that identifies the contents. The stream head processes
STREAMS-related operations from the application and performs the bidirectional
transfer of data and information between the application and messages queue.
6.2.2.2 Modules
STREAMS can insert one or more modules into a stream between the stream
head and the driver to process data passing through the stream. Each module is
constructed from a pair of queue structures required to implement the
bidirectional and symmetrical attributes of a stream. One queue performs
functions on messages passing upstream through the module. The other queue
performs another set of functions on the downstream messages. Each of the two
queues in a module generally have distinct functions, that is, unrelated
processing procedures and data. The queues operate independently, but if the
developer specifically programs the module functions to perform sharing,
messages and data can be shared. Each queue in a module can contain or point
to:
•
Messages
•
Processing procedures
•
Data
Although depicted as distinct from modules, the stream head and the stream end
also contain a pair of queues.
6.2.2.3 Stream End
The stream end is a module in which the module processing procedures are the
driver routines. The procedures in the stream end are different from those in
other modules because they are accessible from an external device and the
STREAMS mechanism allows multiple streams to be connected to the same
driver (see Figure 37 on page 122).
The driver can be a device driver providing interface between kernel space and
an external communication device or an internal pseudo device driver. A pseudo
device driver is not directly related to any external device, and it performs
functions internal to the kernel. Device drivers must transform all data and
Chapter 6. APIs: COMIO, NPI and DLPI
119
status or control information between STREAMS message format and their
external data representation.
6.2.3 Benefits of STREAMS
The STREAMS-standard-based interfaces provide a portable environment.
6.2.3.1 Two Main Benefits
Creating Service Interfaces: STREAMS allows easy creation of modules that
offer standard data communications services to any neighboring application
program, module or device driver. This service interface consists of a specified
set of messages and the rules for allowable sequences of these messages
across the boundary of the modules. A module that implements a service
interface will receive a message from a neighbor and respond with an
appropriate action based on the specific message received and the preceding
sequence of messages.
STREAMS Modularity: As we have just seen, the basic components in a
STREAMS implementation are referred to as modules. These modules, which
reside in the kernel, offer a set of processing functions and associated service
interfaces. From the user level, modules can be dynamically selected and
interconnected to provide any rational processing sequence. This STREAMS
modularity allows:
•
User-level programs that are independent of underlying protocols and
physical communication media
•
Network architectures and high-level protocols that are independent of
underlying protocols, drivers and physical communication media
•
High-level services that can be created by selecting and connecting low-level
services and protocols
•
Enhanced portability of protocol modules, resulting from STREAMS′
well-defined structure and interface standard
6.2.3.2 Consequences of these Two Main Benefits
Protocol Portability: This architecture allows you to use the modules with
different drivers on different machines. Figure 34 shows an X.25 protocol module
used with different drivers on different machines by implementing compatible
service interfaces.
Figure 34. The Portability of the STREAMS Architecture
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Protocol Substitution: Alternative protocol modules and device drivers can be
interchanged on the same machine if they are implemented to equivalent service
interfaces.
Protocol Migration: If the modules are written to comply with industry-standard
service interfaces (called, in that case, protocol modules ), it allows easier
migration. An illustration is shown in Figure 35 where functions are migrated
between kernel software and front-end microcode. We can see in this example
that the transport protocol module can be connected identically to either an X.25
module or X.25 driver that has the same service interface. So this mechanism
allows you to rapidly incorporate technology advances since only one layer of
the software architecture has to be modified.
Figure 35. Easy Migration with the STREAMS Architecture
Module Reusability:
Modules may be reused in different streams.
Figure 36. Reusability of STREAMS Modules
Chapter 6. APIs: COMIO, NPI and DLPI
121
6.2.3.3 STREAMS Facilities
STREAMS provides developers with integral functions, a library of utility routines
and facilities that expedite software design and implementation:
•
Buffer management: Maintains STREAMS′ own and independent buffer pool
•
Scheduling: Incorporates STREAMS′ own scheduling mechanism
•
Asynchronous operation of STREAMS and user processes: Allows
STREAMS-related operations to be performed efficiently from user level
•
Flow control: Conserves STREAMS memory and processing resources
•
Error and trace logs: Allow for debugging and administrative functions
•
Multiplexing: Allows for processing interleaved data streams such as those
that occur in X.25 (SVCs and PVCs). See Figure 37.
Figure 37. Multiplexing Facility of the STREAMS
6.2.4 How to use STREAMS
Application programmers can take advantage of the STREAMS facilities by using
a set of system calls, subroutines, utilities and operations. The following is a
description of the tools available. Examples of use will be found in the later
sections, where NPI and DLPI APIs are described.
6.2.4.1 Subroutines
STREAMS subroutines include:
122
open
Opens the stream to the specified driver. A stream is created on the
first open subroutine to a character special file corresponding to a
STREAMS driver. For instance, with the X.25 LPP, the /dev/x25pkt
packet driver is already available, and so you have only to open the
stream with the open subroutine (dev=open″ / dev/x25pkt″ , O_RDWR).
close
Closes a stream (closedev).
read
Reads data from a stream. Data is read in the same manner as
character files and devices.
write
Writes data to a stream. Data is written in the same manner as
character files and devices.
poll
Notifies the application program when selected events occur on a
stream.
RS/0000 X.25 Cookbook
6.2.4.2 System Calls
STREAMS system calls include:
getmsg
Receives the message at the stream head. We will see in the next
section how this system call will be used to get the primitive message
in the stream.
Example:
rc = getmsg(dev, &ack_ctl, (struct strbuf *)NULL, &getflags);
putmsg
Sends a message downstream. As above, we will see in the next
section how this system call will be used to put the primitive message
on the stream.
Example:
rc = putmsg(dev2, &req_ctl, (struct strbuf *)NULL, 0);
getpmsg
Receives the priority message at the stream head.
putpmsg
Sends a priority message downstream.
6.2.4.3 Operations
Operations include:
ioctl
The ioctl subroutine allows you to perform functions specific to a
particular device. A set of generic STREAMS ioctl operations (named
streamio operations) support a variety of functions for accessing and
controlling streams. The two streamio operations used in the samples
described below are the I_PUSH and I_POP, which respectively allow to
push and pop a module in a stream already opened. The modules
manipulated in this manner are called pushable modules, in contrast
to the modules contained in the stream head and stream end. For
example, to push a new module in a stream, you do the following
streamio operation: ioctl(dev, I_PUSH, ″npi″ ) . See Figure 39 on
page 124 for an illustration of the STREAMS pushing mechanism.
6.3 NPI API
To better understand how to use the NPI, before we describe the NPI samples,
we briefly present the NPI implementation on the RS/6000. More details are
available on the NPI in the AIXLink/X.25 Version 1.1 for AIX: Guide and Reference
manual.
6.3.1 NPI Implementation on the RS/6000
The Network Provider Interface (NPI) consists of a set of primitives defined as
STREAMS messages that provide access to the network layer services. The
primitives are transferred, as STREAMS messages, between the network service
(NS) user entity (data space of a user process) and the NS provider (STREAMS
kernel data space).
Chapter 6. APIs: COMIO, NPI and DLPI
123
Figure 38. NPI Components
A NPI primitive can be one of the following types:
User-originated
These primitives make requests to the NS provider or respond to an
event of the NS provider. They are processed by the putmsg system
call.
Provider-originated
These primitives are either confirmations of a request or are
indications to the NS user that the event has occurred. They are
processed by the getmsg system call.
The open subroutine makes the stream available:
•
open(″ / dev/x25pkt″ , O_RDWR);
The streamio operation pushes the NPI module in the stream:
•
ioctl(dev, I_PUSH, ″npi″ ) ;
The building of a stream is illustrated by the Figure 39.
Figure 39. The Building of a NPI Stream
The NPI allows you to access the packet layer (layer 3 in the OSI Reference
Model) and provides a connection-mode communication, which allows you to
build:
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•
Virtual circuits
•
Data transfer by a pre-established path
•
Data transfer reliability
Since the interface is standard, multiple NPI applications can access the X.25
protocol code.
6.3.2 NPI Primitives Available on the RS/6000
A set of primitives is available to establish a connection, transfer data and
terminate a connection:
1. Local Management Primitive
These primitives are called to open or close a stream connected to the NPI
module. They also manage options supported by the NPI module and report
information on its supported parameter values.
2. CONS Primitive Format and Rules
A network connection, once established, can be seen as a pair of queues
linking two network addresses or X.25 hosts. There is one queue for each
direction of information flow, and each queue provides a control function for
its information flow. The different groups of CONS primitives are:
•
Connection Establishment Primitives
•
Normal Data Transfer Primitives
•
Receipt Confirmation Service Primitives
•
Expedited Data Transfer Service Primitives
•
Reset Service Primitives
•
Network Connection Release Primitives
More details on the use of these primitives are available in the AIXLink/X.25
Version 1.1 for AIX: Guide and Reference .
6.3.3 Use of the Primitives
Each time you want to use a primitive, you must perform the following steps:
1. Space management
Allocate and zero out space for the primitive you will invoke.
This is an example for the N_BIND_REQ primitive :
listen_call = (char *) malloc(NPI_MAX_CTL);
bzero(listen_call, NPI_MAX_CTL);
If needed, allocate and zero out space for the data associated with the
primitive.
2. Structures
Build the structure(s) needed for the primitive you are going to invoke:
•
Build the primitive by filling up the structure associated with the
primitive. This kind of structure must be filled when the primitive is
user-originated ( putmsg()).
Chapter 6. APIs: COMIO, NPI and DLPI
125
•
Build the control structure. This structure must be filled when the
primitive is user-originated ( putmsg()) and provider-originated ( getmsg()).
•
Build the data structure. This structure must be filled when the primitive
is provider-originated ( getmsg()).
3. System calls
Call the putmsg() system call to put the primitive message on the stream if
the primitive is user-originated.
Call the getmsg() system call to get the primitive message in the stream if
the primitive is provider-originated.
4. Verification
If you have just done a getmsg() system call, verify that you have received
the right primitive.
5. Deallocation of memory
Free up the memory allocated earlier:
free(listen_call);
Once the X.25 software is installed on a system, the NPI module is made
available, and then applications that link to the streams library are able to
access the NPI module.
6.3.4 Description of the NPI Samples Available with the LPP
The following two diagrams describe the structure of the two programs which
allow you to transfer data between two X.25 hosts by using the NPI. Once you
have set up the right values for the line parameter, the called/calling NUA and
the data to send, you first run npiserver and then npiclient.
These programs are located in the /usr/lpp/sx25/samples/npi directory on AIX
Version 3 machines and in the /usr/samples/sx25/npi directory on AIX Version 4
machines.
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Figure 40. Structure of the npiserver.c Program
Chapter 6. APIs: COMIO, NPI and DLPI
127
Figure 41. Structure of the npiclient.c Program
6.4 DLPI API
To better understand how to use the DLPI, before we describe the DLPI samples
we briefly present the DLPI implementation on the RS/6000. More details are
available on the DLPI interface in the AIXLink/X.25 Version 1.1 for AIX: Guide and
Reference .
Note: To use the DLPI layer on a port, the Enable DLPI interface ONLY
parameter must be set to yes using the Change / Show X.25 General
Parameters SMIT menu. When this is done, only the frame and physical
levels can be used. Since the packet level will not be activated, the port
can no longer be used for packet level applications such as TCP/IP, PAD
and others.
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6.4.1 DLPI Implementation on the RS/6000
The data link layer (layer 2 in the OSI model) is also referred to as the frame or
LAP-B layer. This layer is responsible for the transmission and error-free
delivery of bits of information over a physical communication medium.
The Data Link Provider Interface (DLPI) provides point-to-point data
communication and is designed for two systems connected back to back over a
communication link. In the X.25 LPP, this is provided through a
connection-oriented subset of the DLPI specification. It specifies an interface to
the services of the data link layer as Figure 42 illustrates.
Figure 42. DLPI Components
The data link interface is the boundary between the network and data link layer
of the OSI Reference Model. The network layer entity, which is usually the X.25
layer, is the user of the services of the data link interface. This user is DLPI′ s
user application and is sometimes referred to as the Data Link Service (DLS)
user. The DLPI layer which provides the programming interface is referred to as
the DLS provider. This interface consists of a set of primitives that provide
access to the link layer services. The service primitives that make up
kernel-level interfaces are defined as STREAMS messages that are transferred
between the user and provider of the service. DLPI is targeted for STREAMS
protocol modules that either use or provide data link services.
6.4.2 Establishment of a Stream to DLPI
The first step you have to do when you want to use the direct access to the
frame layer on a port is to enable the DLPI, so you have to set the Enable DLPI
interface only field of the General Parameters screen to yes when you set up the
port parameters. This disables the packet layer X.25 access, and regular X.25
applications cannot use the port. Neither a COMIO nor a TCP/IP interface is
authorized.
Set one of the ports in passive-wait mode; this is done by setting the frame
attributes from SMIT.
The user has to establish a stream to DLPI before DLPI primitives can be used
by the application. To establish a stream, the user binds to the frame layer. Only
one application per port can bind to the frame layer. Once bound to a stream,
the application can send primitives to DLPI to establish a connection and to
Chapter 6. APIs: COMIO, NPI and DLPI
129
transfer data. When an application wishes to terminate, it disconnects the link
and unbinds from its stream.
6.4.3 DLPI Primitives Available on the RS/6000
There are two groups of DLPI primitives.
6.4.3.1 Local Management Service Primitives
This subset of primitives are in charge of the information reporting, attach and
bind/unbind services of DLPI. Once a stream has been opened by a DLS user,
these primitives initialize the stream and prepare it for use.
6.4.3.2 Connection Mode Service Primitives
These primitives are in charge of the connection-mode service of the data link
layer. They may be split in four different subsets:
•
Connection Establishment Primitives
•
Data Transfer Primitives
•
Connection Release Primitives
•
Reset Primitives
6.4.4 Description of the DLPI Samples Available with the X.25 LPP
The two following diagrams describe the structure of the two programs which
allow you to transfer data between two hosts using the frame-level DLPI
interface.
The DLPI client and server sample programs have the following syntax:
dlpiclient [-b #] [-p #] [-n #]
[-?] [-h]
dlpiserver [-b #] [-p #] [-n #]
[-?] [-h]
The flags specify the following:
-b board number
-p physical port number
-n number of frames to be sent
-?/-h returns usage statement
If no command line arguments are passed, the programs default to the values
specified in the common.h file. The size of the info frames can be modified by
changing the buf_sz value in common.h.
These programs are located in the /usr/lpp/sx25/samples/npi directory on AIX
Version 3 machines and in the /usr/samples/sx25/npi directory on AIX Version 4
machines.
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Figure 43. Structure of the dlpiserver.c Program
Chapter 6. APIs: COMIO, NPI and DLPI
131
Figure 44. Structure of the dlpiclient.c Program
6.5 COMIO API
The X.25 LPPs provide the COMIO interface to maintain compatabilitly with the
previous AIX X.25 product.
6.5.1 COMIO Definition
COMIO stands for Common Input/Output. COMIO emulates the device driver
interface supported in previous releases of AIX X.25. This allows the user-space
library API (available in AIX V.3 X.25 support) and the codes written to the device
driver interface to work unchanged. As the library API is still available in the
X.25 LPP, all the applications written over this library work without recompilation.
Figure 45 on page 133 illustrates COMIO emulation.
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Figure 45. COMIO Emulation
The COMIO emulation is not intended for new program development but more
for compatibilities.
This library API and the device driver interface are detailed in Chapter 12 of the
AIXLink/X.25 Version 1.1 for AIX: Guide and Reference manual. So we shall only
briefly describe the use of the API and the samples made available at X.25 LPP
installation.
The X.25 application programming interface functions are at a level slightly
above the packet level.
6.5.2 Using COMIO
Once COMIO is configured for an X.25 port, you can use the xtalk tool or a
user-developed application.
6.5.2.1 Enabling COMIO
To allow use of this API, the COMIO emulation function must be configured on
the X.25 ports (sx25a n ). To do this, select the Add Comio Interface to Port in the
Manage X.25 Ports menu. It will create a device entry with the same name that
would have been generated by the base AIX Version 3 X.25 support (x25s n ).
6.5.2.2 COMIO Subroutines
You need access to a C compiler because the X.25 API includes a library of C
subroutines that use the services of the COMIO emulator. Applications call
these subroutines to access X.25 functions.
The subroutines are split into four groups:
•
Initialization and termination subroutines
•
Network subroutines
•
Counter subroutines
•
Management subroutines
Chapter 6. APIs: COMIO, NPI and DLPI
133
The X.25 API subroutines are kept in the /usr/lib/libx25s.a library. The API
subroutines are called using standard C conventions.
Each subroutine is detailed in the Technical Reference: Communications manual,
Volume 3, Chapter 11.
6.5.2.3 COMIO structures
The subroutines use a number of structures to pass information between the
X.25 functions and the application program. The /usr/include/x25sdefs.h header
file describes all the structures used (also described in the Files Reference
manual).
6.5.2.4 X.25 Error Codes
The X.25 subroutines set the x25_errno and errno flags to indicate error
conditions.
If an error condition results from an X.25 API subroutine call, it is indicated in
one of the following ways:
•
For X.25-specific error conditions, the x25_errno flag indicates the error, for
example, X25ACKREQ. The errno flag is not set in these conditions.
•
For other error conditions, the x25_errno flag is set to X25SYSERR and the
errno flag indicates the error, for example, EFAULT .
The API Error Codes section, on page 13-19 of the Communication
Programming Concept manual, lists the error codes that may be returned by
X.25 subroutines.
6.5.3 X.25 Example Programs
To help you learn how to use the X.25 subroutines, there are two pairs of
example programs. One pair demonstrates the use of a switched virtual circuit,
and the other the use of a permanent virtual circuit.
These programs are located in the /usr/lpp/sx25/samples/comio directory on AIX
Version 3 and in the /usr/samples/sx25/comio directory on AIX Version 4
machines:
•
svcxmit.c: Make a call using an SVC
svcrcv.c: Receive a call using an SVC
pvcxmit.c: Send data using a PVC
pvcrcv.c: Receive data using a PVC
•
•
•
Each of the example programs has variables to which values are assigned at the
start: calling_addr, called_addr, link_name and log_chan_num. You should
customize these values in accordance to your own environment before running
the programs.
To compile the example programs, use the following commands:
#
#
#
#
#
cd
cc
cc
cc
cc
/usr/samples/sx25/comio (or cd /usr/lpp/sx25/samples/comio)
-o svcxmit svcxmit.c -lx25s
-o svcrcv svcrcv.c -lx25s
-o pvcxmit pvcxmit.c -lx25s
-o pvcrcv pvcrcv.c -lx25s
To run a program, type the name of the executable file at the shell prompt.
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Note: Run the programs in pairs: svcxmit with svcrcv and pvcxmit with pvcrcv.
(These two last programs can be run only if you use permanent virtual
circuits.) The programs which receive data must be run first: svcrcv and
pvcrcv.
For more details about these programs, please refer to AIXLink/X.25 Version 1.1
for AIX: Guide and Reference manual.
Chapter 6. APIs: COMIO, NPI and DLPI
135
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Chapter 7. TCP/IP Setup
This section documents the steps required to configure TCP/IP on an X.25
network.
7.1 Introduction
AIX Version 3.2 and AIX Version 4.1 implement the 4.4 BSD Reno level of TCP/IP
and support the following Internet Request For Comments (RFC):
RFC 1356 IP over X.25
This RFC specifies a standard adopted by CSNET, the VAN gateway and other
organizations for the transmission of IP datagrams over the X.25-based public
data networks.
An X.25 virtual circuit is opened on demand when a datagram arrives at the
network interface for transmission. A virtual circuit is closed after some
period of inactivity. A virtual circuit may also be closed if the interface runs
out of virtual circuits.
Standards:
1. The first octet in the Call User Data field (the first data octet in the Call
Request Packet) is used for protocol demultiplexing. The value of hex CC
(binary 11001100, decimal 204) is used to mean Internet Protocol.
2. IP datagrams are sent as X.25 complete packet sequences . That is,
datagrams begin on packet boundaries and the M-bit (More data) is used
for datagrams that are larger than one packet. There are no additional
headers or other data in the packets.
3. Either site may close a virtual circuit. If the virtual circuit is closed or
reset while a datagram is being transmitted, the datagram is lost.
This chapter describes how to configure
and AIX Version 4.1 with the X.25 LPP.
the X.25 LPP configuration described in
Setup” on page 43 before trying to use
TCP/IP over X.25 on AIX Version 3.2.5
You must have successfully completed
Chapter 3, “X.25 LPP Installation and
TCP/IP.
The steps are described in the subsequent sections. The main tool used in the
setup is SMIT, but some AIX commands will also be used at the proper time.
 Copyright IBM Corp. 1996
137
Setup and Test of TCP/IP Connection with SVC
1. Add entries for the local and remote hosts in /etc/hosts with
smit mkhostent
2. Initialize and start the IP/X.25 interface:
•
•
•
Start smit mkinet1xs.
Select the sx25a0 X.25 LPP Port.
Enter the local X.25 IP address and the IP network mask.
3. Add a route for each remote host connected via X.25 to IP networks
different from the IP network ID of the X.25 interface:
•
•
Start smit mkroute
Enter:
− The destination type as host
− The remote X.25 hostname as DESTINATION address
− The local X.25 hostname as GATEWAY address
− The number 0 as the METRIC or number of hops to destination
gateway.
4. For each remote host, create an entry in the IP hostname to NUA
translation table:
•
•
Start smit mksx25
Enter the remote HOSTNAME, and its NUA
5. Verify that everything is correct with netstat -r.
6. Test the connection to a remote host with ping.
If you plan to use a PVC instead of an SVC for the IP communications, change
item 4 to:
4. For each remote host, create an entry in the translation table from IP
hostname to PVC number:
−
−
Start smit mksx25p.
Enter the remote IP host name, the corresponding logical channel
number and the X.25 LPP port number.
7.2 TCP/IP X.25 Connection Setup and Test
Figure 46 on page 139 shows our two hosts kili and fili. We have assigned them
the X.25 hostnames: kilix and filix, and IP addresses: 9.3.5.205 and 129.35.1.93.
You have probably noticed that our two hosts do not belong to the same IP
network and are not even in the same IP network address class. This is
deliberate, because IP hosts connected through X.25 generally belong to different
IP networks.
We will describe the customization process for kili. It is similar for fili.
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RS/0000 X.25 Cookbook
Figure 46. Test Configuration for TCP/IP
7.2.1 Creating Entries in /etc/hosts
This step can be skipped only if DNS is used and AIX is connected to the
nameserver on a LAN. IF the network initialization script /etc/rc.net starts
building the IP to NUA translation table before the connection to the nameserver
is established, it will not find all the X.25 remote hostnames in /etc/hosts, it fails
and IP communications over X.25 will not be possible.
Create an entry for the local X.25 host (kilix) as well as for the remote X.25 hosts
by using the following SMIT menu sequence:
Communications Applications and services
→
TCP/IP
→
Further Configuration
→
Name Resolution
→
Host Table
→
Add a Host
Or use the fastpath: smit mkhostent.
Add a Host Name
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* INTERNET ADDRESS (dotted decimal)
* NAME
ALIAS(ES) (if any - separated by blank space)
COMMENT (if any - for the host entry)
[Entry Fields]
[9.3.5.205]
[kilix.itsc.austin.ibm.>
[kilix]
[kili on X.25]
This example was for the local X.25 host kilix. We have also added the hostname
filix at address 129.35.1.93 corresponding to the remote host fili.
Chapter 7. TCP/IP Setup
139
7.2.2 Initializing and Starting the IP/X.25 Interface
If you have not defined any other TCP/IP attachment, use the fastpath smit
mktcpip to configure TCP/IP and start an interface. In the other cases, just add
an interface by using the following sequence of SMIT menus:
Communications Applications and Services
→
TCP/IP
→
Further Configuration
→
Network Interfaces
→
Network Interface Selection
→
Add a Network Interface
→
Add a X.25 LPP Network Interface
Or with the fastpath: smit mkinet1xs, select your X.25 LPP Port, and then
configure the interface.
X.25 LPP Port
Move cursor to desired item and press Enter.
sx25a0 Available 00-04-00-00 X.25 Port
Add a X.25 LPP Network Interface
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
* Internet ADDRESS (dotted decimal)
Network MASK (hexadecimal or dotted decimal)
[9.3.5.205]
[255.255.255.0]
The X.25 LPP does not attempt a connection to the X.25 network while
configuring the IP/X.25 interface xs0. You can get an OK message from SMIT
even if your X.25 connection is down.
To check if the xs0 interface is up and running try:
# ifconfig xs0
xs0: flags=80a0043<UP,BROADCAST,RUNNING,ALLCAST,MULTICAST>
inet 9.3.5.205 netmask 0xffffff00 broadcast 9.3.5.255
On AIX Version 3.2.5 systems try:
# netstat -r
Routing tables
Destination
Gateway
Netmasks:
(root node)
(0)0 ff00 0
(0)0 ffff ff00 0
(root node)
Route Tree for Protocol Family 2:
(root node)
default
eze
9.3.1
kili
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Flags Refcnt Use
UG
U
0
14
Interface
27066
18963
tr0
tr0
9.3.5
127
(root node)
kilix
loopback
U
U
0
0
181
13
xs0
lo0
Route Tree for Protocol Family 6:
(root node)
(root node)
On AIX Version 4.1 systems try:
# netstat -r
Routing tables
Destination
Netmasks:
255.255
255.255.255
Gateway
Flags Refcnt Use
Route Tree for Protocol Family 2:
default
eze
9.3.1
kili
9.3.5
kilix
127
loopback
UG
U
U
U
Interface
0
14
0
0
27066
18963
181
13
tr0
tr0
xs0
lo0
7.2.3 Adding Routes for the Remote Systems
When we defined the xs0 attachment, we created an implicit route for the IP
network corresponding to the IP address and the netmask we have set. In our
case, the network 9.3.5 is associated with xs0. If we want to communicate with
systems not belonging to this network, we must add routes . In this particular
case, the gateway is the local host itself, kilix.
Add Static Route
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* DESTINATION TYPE
* DESTINATION Address
(dotted decimal or symbolic name)
* GATEWAY Address
(dotted decimal or symbolic name)
* METRIC (number of hops to destination gateway)
[Entry Fields]
[host]
[filix]
[kilix]
[0]
We can now verify with netstat -r that the route to filix is correct:
# netstat -r
Routing tables
Destination
..
.
default
filix
..
.
Gateway
Flags
Refcnt Use
Interface
eze
kilix
UG
UH
0
0
tr0
xs0
Create a route, in the same way, on fili to access kilix.
27066
0
.
Chapter 7. TCP/IP Setup
141
7.2.4 Mapping IP Addresses to X.25 NUAs
7.2.4.1 Attachment to the Defense Data Network (DDN)
AIX 3.2 and AIX 4.1 conform to RFC 1236 “IP to X.121 Address Mapping for DDN,”
which defines an algorithm that automatically determines the NUA based on the
Internet address. Choosing the “DDN” network identifier invokes this algorithm
in place of the x25ip tables. With the X.25 LPP, you can use Class A, B and C
Internet addresses when working with DDN (the RFC lists Class B and C as
optional).
7.2.4.2 For All Other Network Identifiers
For all other network types, the x25ip table maps TCP/IP Internet addressing to
the X.121 Network User Address (NUA). This table is maintained via the SMIT
X.25 LPP IP/X.25 Host Entry menu.
We now create, for each remote host, an entry in this table. From the first menu
of the SMIT interface, select:
Communications Applications and Services
→
TCP/IP
→
Further Configuration
→
Network Interfaces
→
Network Interface Selection
→
X.25 LPP IP Host Configuration
→
Add a X.25 LPP IP Host Entry
→
Add a Switched Virtual Circuit (SVC) X.25 LPP IP Host Entry
Or use the fastpath: smit mksx25s.
Add INTERNET / X.25 SVC Host Entry
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* Remote HOSTNAME
* Remote DTE Address
---------- Optional X.25 Facilities ----------RECEIVED data PACKET size
TRANSMITTED data PACKET size
RECEIVED data WINDOW size
TRANSMITTED data WINDOW size
CLOSED USER GROUP selection
CLOSED USER GROUP WITH OUTGOING ACCESS selection
Recognized Private Operating Agency (RPOA)
User-Defined Facilities
---------- CALL USER Data -------------------Note: RFC-1356 (supersedes RFC-877) mandates
the first byte of call user data is 0xcc. If you
do not put ′ cc′ as the first byte, SMIT
will put it there for you.
Call User Data
[Entry Fields]
[filix]
[3106010761]
[]
[]
[]
[]
[]
[]
[]
[]
#
+
+
[]
Also create an entry for kilix on the Internet/X.25 SVC translation table of filix.
This is necessary even if only kili makes the calls.
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RS/0000 X.25 Cookbook
#
#
#
#
Note: It may happen that the translation table gets corrupted and contains
duplicate entries. The simplest solution is to remove this table and create
another. Here is how to remove it:
# cd /etc/objrepos
# odmdrop -o X25ip
This table will be re-created automatically with the default values. Simply
add your new entries with SMIT.
You may also save the file /etc/objrepos/X25ip. This file can be restored
and the table reinitialized by entering the command:
# x25ip
7.2.5 Testing the Connection
To test the TCP/IP connection, use the ping command. This command will start
to send packets of 64 bytes across the network. To stop this command, hit the
Interrupt key, usually Ctrl-C
# ping filix
PING filix.itsc.austin.ibm.com: (129.35.1.93): 56 data bytes
64 bytes from 9.3.5.62: icmp_seq=1. time=229. ms
64 bytes from 9.3.5.62: icmp_seq=2. time=106. ms
64 bytes from 9.3.5.62: icmp_seq=3. time=106. ms
You should receive a message with zero percent of packets lost. This
demonstrates that a good connection has been established. A small percentage
of packet loss can be attributed to call completion time and should not be of
concern.
For the last test, if reasonable, shut down and reboot the system. Then try the
ping command again. If it doesn′t work, you have a problem with the execution
of the /etc/rc.net script, which is reported in /tmp/rc.net.out. For more
information on TCP/IP problem determination, see 9.8, “Diagnosing TCP/IP
Problems” on page 191. This verifies your TCP/IP X.25 configuration.
Notes:
•
A virtual call is made when the first session with a remote system is
established.
•
Several IP sessions can share the same virtual circuit. Once an X.25
communication has been established, all IP traffic between two systems will
share the same virtual circuit. Only one SVC is needed for communication
between two systems.
•
The X.25 virtual circuit is left connected for a period of time after the last IP
session has been closed. This is so the cost of call establishment is not
incurred if the remote system is contacted again in the near future (which is
reasonably likely). This time delay, which is approximately 20 minutes, is
modifiable with the Network Options ( no) command using the arpt_killc
option. For example, to clear the virtual circuit after five minutes of
inactivity:
# no -o arpt_killc=5
Note: The no command is used to modify some network parameters until the
system is rebooted. If you want your new values to remain
Chapter 7. TCP/IP Setup
143
unchanged after each system boot, you have to add the command at
the end of the /etc/rc.tcpip file.
•
To clear a TCP/IP X.25 virtual connection, both SVC and PVC, use the arp -d
command. For example, to clear an existing virtual connection between kilix
and filix, type on filix:
# arp -d filix
•
To check the state of PVC or SVC connections, enter:
# arp -a
If the arp entries for the PVCs or SVCs are missing, enter the following to
restore:
# x25ip
•
If the IP address of a remote host is changed at the name server, enter the
following command to update the IP/X.25 translate table:
# x25ip
•
X.25 packets are buffered by TCP/IP using system mbufs . A shortage of
mbufs may result in a performance degradation. You can display the number
of mbufs assigned with:
# lsattr -E -l sys0
Or look at the thewall parameter with:
# no -a
You can display the usage of mbufs with:
# netstat -m
To change the maximum number of mbufs, use:
# chdev -l sys0 -a maxmbuf=.....
Or:
# no -o thewall=.....
7.2.6 Suppressing the X.25 LPP IP Interface
If you want to modify some X.25 parameters and you have defined an xs0
interface, SMIT will display the following message:
Method error (/etc/methods/chgsx25):
0514-029 Cannot perform the requested function because a
child device of the specified device is not in a correct state.
To avoid this problem, you will have to remove the xs0 interface with the
fastpath smit rminet. When the modification is done, you re-create the IP/X.25
attachment with fastpath smit mkinet1xs. Verify also that there is no other
application using the X.25 line, such as x29d.
Note: At your own risk, you may also bring the interface down by using the
following command:
# rmdev -lxs0
To re-create it:
# mkdev -lxs0
# x25ip
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Remember that, in this case, the attachment definition will be reset after
the next system reboot.
7.3 Requesting the Use of a Facility with TCP/IP
It is possible to customize TCP/IP so that it uses optional X.25 facilities. For each
host entry in the x25ip table, you can configure the use of X.25 facilities. From
the SMIT menu, select:
Communications Applications and Services
→
TCP/IP
→
Further Configuration
→
Network Interfaces
→
Network Interface Selection
→
X.25 LPP IP Host Configuration
→
Change / Show a X.25 LPP IP Host Entry
Or use the fastpath: smit chinetsx25.
Change/Show an X.25 LPP IP SVC Host Entry
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* Remote HOSTNAME
* Remote DTE Address
---------- Optional X.25 Facilities ----------RECEIVED data PACKET size
TRANSMITTED data PACKET size
RECEIVED data WINDOW size
TRANSMITTED data WINDOW size
CLOSED USER GROUP selection
CLOSED USER GROUP WITH OUTGOING ACCESS selection
Recognized Private Operating Agency (RPOA)
User-Defined Facilities
---------- CALL USER Data -------------------Note: RFC-1356 (supersedes RFC-877) mandates
the first byte of call user data is 0xcc. If you
do not put ′ cc′ as the first byte, SMIT
will put it there for you.
Call User Data
[Entry Fields]
[filix]
[3106010761]
[]
[]
[]
[]
[]
[]
[]
[]
#
+
+
#
#
#
#
[]
As you can see in this panel, you don′t need to code the more common facility
requests yourself. For the most common facilities, such as non-standard packet
size or window size request, just enter the corresponding parameters and SMIT
will build the request for you. If the facility you want to use is not listed, enter
the facility request in hexadecimal in the User-Defined Facilities field.
The example shows how we have changed the packet sizes and requested to
reverse the charge each time we call the TCP/IP host filix:
Chapter 7. TCP/IP Setup
145
Change/Show an X.25 LPP IP SVC Host Entry
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* Remote HOSTNAME
* Remote DTE Address
---------- Optional X.25 Facilities ----------RECEIVED data PACKET size
TRANSMITTED data PACKET size
RECEIVED data WINDOW size
TRANSMITTED data WINDOW size
CLOSED USER GROUP selection
CLOSED USER GROUP WITH OUTGOING ACCESS selection
Recognized Private Operating Agency (RPOA)
User-Defined Facilities
---------- CALL USER Data -------------------Note: RFC-1356 (supersedes RFC-877) mandates
the first byte of call user data is 0xcc. If you
do not put ′ cc′ as the first byte, SMIT
will put it there for you.
Call User Data
[Entry Fields]
[filix]
[3106010761]
[256]
[256]
[]
[]
[]
[]
[]
[0101]
#
+
+
#
#
#
#
[]
Here is the x25mon trace of the call packet that is generated when we do a ping:
sx25a0 PS 0x0014 CALL
dN la:10 lf:5
ld:1 AA31060107613106010760054208080101CC
You will notice that the length of the facilities is 05, facility request for input and
output packet size of 256 is 420808 and the reverse charging request is 0101.
7.4 Changing TCP/IP CUD Values
TCP/IP RFC 877 defines CC as the standard TCP/IP CUD value. By default, the
X.25 LPP sends CUD CC in all outgoing TCP/IP call packets and routes all
incoming call packets with CC to TCP/IP. Some hosts send CC000000 as the CUD
value. For example, in cases where a remote host expects the RISC
System/6000 to generate a CUD of CC000000, the user must customize the CUD
value in the X.25 LPP IP Host Entry (x25ip). From the first menu of the SMIT
interface, select:
Communications Applications and Services
→
TCP/IP
→
Further Configuration
→
Network Interfaces
→
Network Interface Selection
→
X.25 LPP IP Host Configuration
→
Change / Show a X.25 LPP IP Host Entry
Or use the fastpath: smit chinetsx25.
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RS/0000 X.25 Cookbook
Change/Show an X.25 LPP IP SVC Host Entry
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* Remote HOSTNAME
* Remote DTE Address
---------- Optional X.25 Facilities ----------RECEIVED data PACKET size
TRANSMITTED data PACKET size
RECEIVED data WINDOW size
TRANSMITTED data WINDOW size
CLOSED USER GROUP selection
CLOSED USER GROUP WITH OUTGOING ACCESS selection
Recognized Private Operating Agency (RPOA)
User-Defined Facilities
---------- CALL USER Data -------------------Note: RFC-1356 (supersedes RFC-877) mandates
the first byte of call user data is 0xcc. If you
do not put ′ cc′ as the first byte, SMIT
will put it there for you.
Call User Data
[Entry Fields]
[filix]
[3106010761]
[]
[]
[]
[]
[]
[]
[]
[]
#
+
+
#
#
#
#
[CC000000]
7.5 Configuring SNMP
We assume that the snmpd daemon is running and all the necessary software
needed to ensure that the snmpd is properly functioning is installed and working.
You can find the X.25 proxy agent x25smuxd and the MIB definitions file
x25smuxd.defs in the /usr/sbin directory.
Data collection from X.25 for SNMP is enabled and disabled by the configuration
methods.
•
Enabled at the time the first port is configured
•
Disabled at the time the last port is unconfigured
Before invoking x25smuxd by the configuration methods at port configuration time,
use the following installation procedure.
1. Log in as root
2. Check to see if the /usr/sbin/x25smuxd.defs file is installed.
3. In the /usr/sbin/x25smuxd.defs file, find the following line:
-- object definitions compiled from RFC1381-MIB { iso 3 6 1 2 1 }
Append every line from this line to the end of the file to the bottom of the
/etc/mib.defs file.
4. Add the following entry to the bottom of the /etc/snmpd.peers file:
″x25smuxd″
1.3.6.1.2.1.10.16
″x25smuxd_password″
5. Add the following entry to the bottom of the /etc/snmpd.conf file:
smux 1.3.6.1.2.1.10.16
x25smuxd_password #x25smuxd
Chapter 7. TCP/IP Setup
147
6. Refresh the snmpd daemon so that it rereads the /etc/snmpd.conf file with
the following command:
refresh -s snmpd
Warning:
1. Only run x25smuxd when you are logged in with root authority.
2. Never start more that one instance of x25smuxd as it can cause conflicts with
the interprocess communication mechanism.
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RS/0000 X.25 Cookbook
Chapter 8. Accessing an SNA Network with X.25
In this chapter, we will use the X.25 connection defined in Chapter 3, “X.25 LPP
Installation and Setup” on page 43, to connect our system kili to an SNA network
and access the S/390 host. To make the connection, we will be using the SNA
Server/6000 V3.1 licensed program product. This product is now marketed as
″Communications Server fo AIX″. The 3270 terminal emulation program we will
be using is 3270 Host Connection Program/6000 (HCON) Version 2.1.
Figure 47. Scenario for an SNA Connection Using X.25
Before we start to configure our system, we will need to understand some
background information on using SNA over X.25, along with the structure and
functions of the SNA product on the RISC System/6000.
This chapter is intended for system administrators responsible for:
 Copyright IBM Corp. 1996
•
Installing AIX SNA Server/6000
•
Configuring the system to match the network to which it is connected
149
•
Keeping the system running
SNA administrators should be familiar with an AIX node and operating
procedures for the AIX operating system. Also, they should know the network to
which the system is being connected and the general concepts of SNA. In
addition, individuals assuming administrative responsibilities should know how
to use the Systems Management Interface Tool (SMIT). Some of the tasks
related to system administration are:
•
Customizing AIX SNA
•
Starting and stopping SNA
•
Defining network security
•
Getting network status
The SNA Server/6000 product provides menu dialogs, commands and
procedures for system administration purposes.
8.1 QLLC with Reference to RISC System/6000 X.25 Support
Qualified Logical Link Control (QLLC) is only for SNA support. It permits the use
of additional link control information that SNA needs, but X.25 does not. QLLC
architecture specifies the mapping between Synchronous Data Link Control
(SDLC) frames and X.25 packets.
When SNA is used over X.25, it uses the Qualifier-bit (Q-bit) in the X.25 packet
header to indicate special link control information. This information is relevant
for SNA control between the two systems communicating with each other, but it
is of no concern to X.25 link control. These qualified packets help SNA to
determine who is calling whom between the two communicating systems, and it
will indicate maximum message sizes and so on.
QLLC must be used in the following situations:
•
When two RISC System/6000s are communicating with each other using SNA
over X.25
•
When a RISC System/6000 is communicating with a host, for example a
System/390, using SNA over X.25
Some systems want to control the segmenting and de-segmenting of messages
themselves, rather than leaving it to the X.25 protocol. They use additional
control on top of X.25 to perform this. The RISC System/6000 does not support
this additional control of Logical Link Control (LLC) headers, imbedded in X.25
packets, to segment messages. The RISC System/6000 will leave it to the X.25
protocol to handle segmenting.
8.2 Introduction to SNA Server/6000
AIX SNA Server/6000 implements two SNA components that control the operation
of the local node in the network. These components are:
•
Physical Unit (PU)
SNA Server/6000 provides the capabilities of a PU Type 2 node.
•
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RS/0000 X.25 Cookbook
Logical Units (LUs) classified as one of the following types:
LU 0
Program-to-program communications
This logical unit is used by certain host database systems (such
as IMS/MVS) and some point-of-sale systems for the retail and
banking industries. Current releases of these products also
support communications using LU 6.2, which is the preferred
protocol for new applications.
SNA Server/6000 supports up to 256 LU 0 type LUs, with primary
and secondary server capabilities:
LU 1
−
LU 0 primary server supports communication with PU type 2
nodes. It provides simple functions that communicate directly
with the SDLC device driver. LU 0 primary servers can only be
used on EIA232D and EIA422A links.
−
LU 0 secondary server supports dependent communication
with a host system, emulating a PU type 2 node. It is an
application written to the generic SNA device driver. LU 0
secondary servers can be used on any of the links supported
by SNA Server/6000.
Host program to RJE workstation
This is used for application programs and single and multiple
device data processing workstations communicating in an
interactive, batch-data transfer or distributed-data processing
environment.
SNA Server/6000 supports LU 1 for dependent communication
using the SNA character string or Document Character
Architecture (DCA) data streams. This enables it to provide
workstation emulation through Transaction Programs (TPs). It
typically supports printing, card reading and card punching
devices. You can write TPs for LU 1 using the Operating System
Subroutines or Library Subroutines Application Programming
Interfaces (APIs).
LU 2
Host program to display workstation
Used by application programs and display workstations to
communicate in an interactive environment. In addition, it is used
by some programs to communicate with hosts that normally
provide output to 3270 display devices. SNA Server/6000 supports
LU 2 for file transfers and for dependent communication using the
SNA 3270 data stream.
LU 3
Host program to 3270 printer
Used by application programs and printers using the SNA 3270
data stream. SNA Server/6000 supports LU 3 for dependent
communications, which enables the SNA server to provide printer
emulation through TPs.
LU 6.2
Advanced Program-to-Program Communications (APPC)
Can be used for communication between two type-5 nodes, a
type-5 node and a type-2.0 or type-2.1 node, or two type 2.1
nodes. This LU type provides more function and greater flexibility
than any previous LU type. Unless you are constrained by
existing hardware or software, LU 6.2 is the logical choice when
developing new applications.
Chapter 8. AIX SNA Server/6000
151
SNA Server/6000 supports independent LU 6.2 for communication
in peer networks and dependent LU 6.2 for communication in
subarea networks. You can write TPs for LU 6.2 using the CPI
Communications, Operating System Subroutines or Library
Subroutines APIs. You can also use the same configuration
profiles and TPs for both independent and dependent LU 6.2.
8.2.1 SNA Application Programming Interfaces (APIs)
SNA Server/6000 provides several APIs, each consisting of a set of subroutines
that enables TPs to communicate with LUs.
Transaction programmers choose APIs depending on the type of LU for which a
TP is written and the requirements of the application. Each TP uses a single
API, but TPs written for the same LU type, using different APIs, can still
communicate with each other.
SNA Server/6000 provides the following APIs. With the exception of CPI
Communications (CPI-C) API, the SNA Server/6000 APIs are supported only on
SNA Server/6000 nodes.
8.2.1.1 CPI Communications API
This API provides a common interface across different SNA platforms. TPs
written to this API can run without modification on nodes that support IBM
Systems Application Architecture (SAA) CPI-C.
This API is used only for LU 6.2 TPs.
8.2.1.2 Operating System Subroutines API
This API uses AIX subroutines to support TPs running under SNA Server/6000. It
can be used to write TPs for LU types 1, 2, 3 and 6.2.
8.2.1.3 Library Subroutines for TP Conversations
This API uses SNA Server/6000 subroutines to support TPs running under SNA
Server/6000. It can be used to write TPs for LU types 1, 2, 3 and 6.2.
8.2.1.4 LU 0 APIs
Two APIs are available for use with LU 0: LU 0 Primary API and LU 0 Secondary
API.
•
The LU 0 Primary API can be used to write TPs to communicate with an LU 0
TP on a PU type 2 node.
•
The LU 0 Secondary API can be used to write TPs to communicate with an
LU 0 TP running on a host.
8.2.1.5 Generic SNA API
This API provides subroutines that interact directly with the PU services
component of SNA Server/6000. These subroutines can be used to program SNA
functions that are not available from SNA Server/6000.
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RS/0000 X.25 Cookbook
8.2.1.6 Network Management APIs
SNA Server/6000 includes two sets of subroutines for network management:
Library Subroutines API and Management Services API.
•
The Library Subroutines API includes network management subroutines that
can be used on a RISC System/6000 workstation in a subarea network.
•
The Management Services API enables a RISC System/6000 workstation
configured as a node in an APPN network to function as a Mangement
Services (MS) entry point.
For more information about SNA Server/6000 APIs, see AIX SNA Server/6000:
Transaction Program Reference .
8.2.2 SNA Configuration Profiles
AIX SNA Server/6000 keeps all network information in structured files called
profiles. It stores the profiles as database files that are controlled by system
data management routines.
The following figure shows the profiles needed to use the 3270 host connection
program with X.25:
Figure 48. Generic AIX SNA Server/6000 Profiles for HCON
Chapter 8. AIX SNA Server/6000
153
The profiles and their functions are as follows:
SNA Node: Describes the operating parameters for SNA Server/6000 on the local
node. This profile is created automatically during SNA Server/6000 installation,
but it can be modified to suit your needs. There can only be one SNA Node
Profile per RISC System/6000.
Control Point: Provides identifying information for the control point (CP) on the
local system - for example the CP name, network name, XID node ID - and
indicates the role of the node in the network. This profile is also created
automatically during SNA Server/6000 installation, but it must be modified to suit
your needs. There can only be one control point profile per RISC System/6000.
Link Definitions: SNA Server/6000 requires information about each link to the
network. The attributes of a link can be divided an into two parts:
•
•
Physical and logical characteristics of a port
Control characteristics of the link station
You specify the attributes for each link using the SNA DLC and Link Station
Profiles.
SNA DLC: Identifies the adapter device driver and specifies the adapter
characteristics. This profile also provides APPN routing and recovery
procedures for all dynamic link stations.
Link Station: Describes the control characteristics that support a link to the
network.
Session: Specifies the characteristics of a local LU and parameters for a session
with a remote LU over a specific link station.
8.2.3 SNA Configuration Database and Commands
SNA Server/6000 maintains two separate Object Database Management (ODM)
databases: the working database and the committed database . The working
database is used as a working area in which profiles can be added and altered.
The committed database contains the set of profiles that SNA Server/6000 uses
while running. The SNA Server/6000 commands are used to maintain the validity
of the two separate databases.
When configuration profiles are added or changed, they are stored in the
working configuration database. Before these profiles can be used, the
verifysna command must be used to ensure that the profiles are correct and
internally consistent. See Figure 49 on page 155.
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RS/0000 X.25 Cookbook
Figure 49. AIX SNA Server/6000 Configuration Process
A set of configuration commands is provided with AIX SNA Server/6000 to allow
you to set up the network. These commands can be accessed directly from the
AIX command line or through the SMIT interface. The commands explained here
are only those used for our example LU 2 setup. For more information on
configuration, see AIX SNA Server/6000: Configuration Reference .
mksnaobj
Creates a profile in the working configuration database.
chsnaobj
Changes the values in an already defined profile in the working
configuration database.
rmsnaobj
Removes a profile.
qrysnaobj
Retrieves the values of all fields, in stanza format, in an already
defined profile.
helpsnaobj
Provides online help for the mksnaobj and chsnaobj commands.
lssnaobj
Lists the profiles in the configuration database that meet a specified
criteria.
Chapter 8. AIX SNA Server/6000
155
verifysna
Verifies that all the profiles in the working database are consistent
and error-free. If the update option is used, the committed database is
changed, provided that all the profiles in the working database verify.
This command does not change the working database in either case.
sna
When used with the options below, controls the SNA server. When
used without arguments, it displays help information for the
command.
-display
Displays SNA status information, including information
about sessions and links, and local directory and topology
databases
-setlogs
Configures the SNA service files (files containing trace and
error information)
-start
Starts SNA, link stations and sessions using various
criteria
-stop
Stops SNA, link stations and sessions using various
criteria
For more detailed information on these and other SNA Server/6000 commands,
see AIX SNA Server/6000: Command Reference .
8.2.4 SNA Server Components
AIX SNA Server/6000 is set of AIX utilities that includes the following
components:
•
Device drivers
•
Kernel extensions
•
Daemon processes
SNA Server/6000 utilities enable TPs running on the RISC System/6000
workstation to access SNA network resources using the AIX input/output (I/O)
device interface.
8.2.4.1 SNA Server/6000 Directories
This section lists the AIX directories that can contain SNA Server/6000 files. The
files may be command files, executable files, configuration files or script files.
/etc/
An AIX directory which contains the rc.sna shell script, used for
automatically starting SNA.
/etc/objrepos/sna/work/
SNA Server/6000 directory containing the configuration profile for the
working database.
/etc/objrepos/sna/verified/
SNA Server/6000 directory containing the configuration profile for the
committed database.
/usr/adm/ras/
An AIX directory containing AIX trace and error logging information.
156
RS/0000 X.25 Cookbook
/usr/bin/
An AIX directory containing AIX and SNA Server/6000 commands.
/usr/include/
An AIX directory containing files to support SNA Server/6000
applications programming.
/usr/lib/
An AIX directory containing libraries to support SNA Server/6000
application programming.
/usr/lib/drivers/
An AIX directory containing SNA Server/6000 device drivers.
/usr/lib/methods/
An AIX directory containing SNA Server/6000 kernel extensions
configuration commands.
/usr/lpp/lu0/
SNA Server/6000 directory containing files to support LU 0 application
programming.
/usr/lpp/lu0/bin/
SNA Server/6000 directory containing LU 0 executable files.
/usr/lpp/lu0/samples
SNA Server/6000 directory containing sample files for LU 0.
/usr/lpp/msg/En_US/
An AIX directory containing the SNA Server/6000 message catalogs.
/usr/lpp/sna/
SNA Server/6000 directory containing installation files and general
information files.
/usr/lpp/sna/bin/
SNA Server/6000 directory containing executable files, daemons and
installation programs.
/usr/lpp/sna/samples/
SNA Server/6000 directory containing sample TPs.
/usr/lpp/sna/samples/bin/
SNA Server/6000 directory containing APPC sample TPs.
/usr/lpp/sna/samples/doc/
SNA Server/6000 directory containing notes on sample TPs and
configuration profiles provided with the LPP.
/usr/lpp/sna/samples/xmpprof/
SNA Server/6000 directory containing sample SNA Server/6000
configuration profiles.
/var/lu0/
SNA Server/6000 directory containing LU 0 configuration data and
trace results.
/var/sna/
SNA Server/6000 directory containing internal error log and trace
data.
Chapter 8. AIX SNA Server/6000
157
8.3 AIX SNA Server/6000 Setup
This section gives a step-by-step description of how to customize SNA Server to
use 3270 emulation over an X.25 network. The setup will correspond to the host
definitions listed in 8.3.3, “Getting Host Definitions” on page 160.
The steps listed in the box are described in the subsequent sections.
AIX SNA Server/6000 Setup
1. Install the SNA Server/6000 LPP
2. Install the appropriate DLC device driver
3. Get host definitions
4. Perform initial node setup
5. Define the SNA profiles for LU 2 setup:
•
Change the SNA control point profile
•
Define the SNA DLC profile
•
Define the SNA link station profile
•
Define the SNA X.25 optional facilities profile
•
Define the SNA session profiles
6. If appropriate, verify the SNA profiles with the update option
7. Start SNA
•
Start the SNA server
•
Start the SNA link station
•
List the current status of SNA
8.3.1 Installation of the AIX SNA Server/6000 LPP
The SNA Server/6000 licensed program product, program number 5765-247,
consists of the following parts:
sna.sna.obj Contains the SNA Server/6000 base program.
sna.lu0.obj Contains the SNA Server/6000 LU 0 facility. Sna.sna.obj is a
prerequisite for this component.
snam language .msg Contains the messages and help information in the specified
language for the run-time environment. If you install multiple
languages for a product, ensure that you install the preferred (or
primary) language first. For example, to install U.S. English as the
primary language, you would install snamEn_US.msg. Sna.sna.obj is
a prerequisite for this component.
Also available as options in the SNA Server/6000 product family are the following
orderable LPPs.
gw.sna.obj
SNA Gateway/6000 Product − requires sna.sna.obj to be installed.
158
RS/0000 X.25 Cookbook
sna.brwsr.obj
DynaText browser utility − used to view SNA Server/6000 softcopy
publications; sna.sna.obj and X11rte.obj are prerequisites for this
component.
sna.usdoc.obj
AIX SNA Server/6000: User ′ s Guide − softcopy publication
(sna.sna.obj and sna.brwsr.obj are prerequisites).
sna.crdoc.obj
AIX SNA Server/6000: Configuration Reference − softcopy publication
(sna.sna.obj and sna.brwsr.obj are prerequisites).
sna.dgdoc.obj
AIX SNA Server/6000: Diagnosis Guide and Messages − softcopy
publication (sna.sna.obj and sna.brwsr.obj are prerequisites).
sna.cmdoc.obj
AIX SNA Server/6000: Command Reference − softcopy publication
(sna.sna.obj and sna.brwsr.obj are prerequisites).
sna.tpdoc.obj
AIX SNA Server/6000: Transaction Program Reference − softcopy
publication (sna.sna.obj and sna.brwsr.obj are prerequisites).
sna.gwdoc.obj
AIX SNA Gateway/6000: User ′ s Guide − softcopy publication
(sna.sna.obj and sna.brwsr.obj are prerequisites).
The licensed program may also contain update files.
8.3.2 Installation of the Data Link Control
Each data link control interface has a special file in the /dev directory.
To show the predefined data link controls:
# lsdev -P -H -c dlc
class type
subclass description
dlc
dlc
dlc
dlc
dlc
dlc
tokenring
sdlc
x25_qllc
fddi
ethernet
IEEE_ethernet
dlc
dlc
dlc
dlc
dlc
dlc
Token-Ring Data Link Control
SDLC Data Link Control
X.25 QLLC Data Link Control
FDDI Data Link Control
Standard Ethernet Data Link Control
IEEE Ethernet (802.3) Data Link Control
Each of the above corresponds to one of the physical interfaces supported by
SNA communications in AIX.
To install the X.25 QLLC Data Link Control for the X.25 Co-Processor, from the
first menu of the SMIT interface, select:
Devices
→
Communication Devices
→
X.25 Co-Processor/2 or Multiport/2 Adapter
→
Services
→
Data Link Controls
→
Add a QLLC Data Link Control
Or use the fastpath: smit cmddlc_qllc_mk
Chapter 8. AIX SNA Server/6000
159
The AIX-generated command is:
mkdev -c dlc -s dlc -t x25_qllc
If using the Portmaster Adapter:
Devices
→
Communication Devices
→
Portmaster Adapter/A
→
Services
→
Data Link Controls
→
Add an SDLC Data Link Control
Or use the fastpath: smit cmddlc_sdlc_mk
The AIX-generated command is:
mkdev -c dlc -s dlc -t sdlc
8.3.3 Getting Host Definitions
Before configuring SNA Server/6000, some information must be requested from
the VTAM administrator for the SNA node to which we will connect. The
following table is the minimum information required for this example:
Table 12. SNA Host Definitions
VTAM Parameter
Value
RISC System/6000 Profile
Network User Address
3106001984
Attachment
IDBLK
071
3270 LU profiles
IDNUM
06000
3270 LU profiles
SSCP ID
20
3270 LU profiles
2
3
3270 LU profiles
LOCADDR
Network User Address: The X.25 address, 3106001984, uniquely identifies the X.25
line to which the S/370 host is attached.
This parameter will be used in the attachment profile definition.
IDBLK
The three hexadecimal digits of this parameter provide an identifier,
or block number, that is unique to each product on the network. For
the RISC System/6000, this number is 071.
IDNUM
The five hexadecimal digits of this ID number distinguish a specific
piece of equipment from all others of a similar kind on the network.
The number usually is given by the VTAM administrator. In our case,
an ID number of 06000 was assigned to our RISC System/6000.
SSCPID
The ID of the controlling System Services Control Point (SSCP) in the
SNA network (decimal value).
LOCCADR These are the local addresses of the 3270 displays and printers in the
3270 cluster. One decimal value is used for each display or printer
connected.
160
RS/0000 X.25 Cookbook
8.3.4 SNA Profiles for an X.25 LU 2
Figure 50 shows the profiles needed to configure a logical unit type 2 (LU 2):
Figure 50. X.25 AIX SNA Server/6000 Profiles for HCON
8.3.5 Performing Initial Node Setup
Initial Node Setup configures the node control point and a single link station. It
enables you to create the basic configuration of SNA Server/6000 while providing
a minimal amount of information. Although we are going to use advanced
configuration to configure the control point, the information we enter in the initial
node setup is required to verify profiles and run SNA Server/6000, so we must
still perform this part.
To enter the initial node setup information from the first menu of SMIT, select:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Initial Node Setup
Or use the fastpath: smit _snainit.
This displays the Initial Node Setup screen:
Chapter 8. AIX SNA Server/6000
161
Initial Node Setup
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
[AUSCP]
appn_end_node
[USIBMRA]
[*]
Control Point name
Control Point type
Local network name
XID node ID
+
Optional link station information:
Link station type
Link station name
* Calling link station?
Remote X.25 station address
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
x.25_svc
[]
yes
[3106001984]
F3=Cancel
F7=Edit
Enter=Do
+
X
F4=List
F8=Image
Here we have defined:
Control Point name:
If you are connecting to a host, the value in this field should match
the CPNAME= entry in the host′s VTAM PU statement.
Control Point type:
Determines whether this machine is to act as an intermediate session
routing node or not. In this case, we have defined that the local
system accesses network services through an associated network
node. It maintains directory information only for the local system.
XID node ID:
If connecting to a host over a switched connection, enter a value to
support the LU definitions. The value should consist of the IDBLK= (a
three digit hexadecimal) and IDNUM= (a five digit hexadecimal) entries
in the VTAM PU definition.
Link station type:
Describes the DLC type for a link station for this node.
Calling link station?:
This value is required if using X.25 link stations using switched virtual
circuits, as well as for token-ring and ethernet link stations.
Remote X.25 station address:
Address of the remote X.25 link station. Must be specified if using
switched virtual circuits.
162
RS/0000 X.25 Cookbook
8.3.6 Setting Up the SNA profiles for LU 2
SNA LU 2 setup requires the modification of several profiles.
8.3.6.1 Changing the Control Point Profile
The control point profile describes the characteristics of the control point on the
local RISC System/6000. A RISC System must have one (and only one) control
point profile. The control point supports multiple independent LU sessions and a
single dependent LU session. When the node participates in an APPN network,
it supports APPN network node and end node functions. The SNA Server/6000
control point acts as both a logical unit (LU) and a physical unit (PU):
•
As an LU, it identifies itself to the CP of the adjacent SNA node during CP-CP
sessions, enabling the node to access APPN support services such directory
searches and route selection.
•
As a PU, the CP automatically assumes control over all available link
stations on the RISC System/6000 and uses them to support APPN
operations with adjacent SNA nodes.
To enter the control point profile information from the first menu of SMIT, select:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Control Point
→
Change/Show a Profile
Or use the fastpath: smit _snacpch.
This displays the Change/Show Control Point Profile screen:
Change/Show Control Point Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
node_cp
[*]
[USIBMRA]
[AUSCP]
[AUSCP]
appn_end_node
[500]
[500]
[128]
* Profile name
XID node ID
Network name
Control Point (CP) name
Control Point alias
Control Point type
Maximum number of cached routing trees
Maximum number of nodes in the TRS database
Route addition resistance
Comments
F1=Help
F5=Reset
F9=Shell
+
#
#
#
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Here we have defined:
Chapter 8. AIX SNA Server/6000
163
XID Node ID:
If connecting to a host over a switched connection, enter a value to
support the LU definitions. The value should consist of the IDBLK= (a
three digit hexadecimal) and IDNUM= (a five digit hexadecimal) entries
in the VTAM PU definition.
Network name:
Distinguishes this network from other networks to which the machine
can be connected. This name combined with the control point name,
forms a unique identifier (the fully qualified name) for this control
point.
Control Point (CP) Name:
If you are connecting to a host, the value in this field should match
the CPNAME= entry in the host′s VTAM PU statement.
Control Point type:
Determines whether this machine is to act as an intermediate session
routing node or not. In this case, we have defined that the local
system accesses network services through an associated network
node. It maintains directory information only for the local system.
Cached routing trees:
This field applies only to network nodes.
Nodes in the TRS database:
This is the maximum number of APPN CPs that can be stored in the
APPN topology routing services (TRS) database. If this CP is an end
node (as in this example), this value should be greater than or equal
to the number of network nodes, end nodes or LEN nodes adjacent to
this node.
Route addition resistance:
This field applies only to network nodes.
8.3.6.2 Defining the Data Link Control Profile
The Data Link Control (DLC) is a set of communications protocols that supports
orderly exchanges of data over a link. The DLC manages a communication
adapter. SNA Server/6000 requires you to supply information about DLC
characteristics in the SNA DLC profile. This profile describes the characteristics
of a communication port on the RISC System/6000 workstation. A single port can
support one or more link stations.
To enter the DLC profile information, from the first menu of SMIT, select:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Links
→
X.25
→
X.25 SNA DLC
→
Add a Profile
Or use the fastpath: smit _snaX25linkmk.
This displays the Add X.25 SNA DLC Profile screen:
164
RS/0000 X.25 Cookbook
Add X.25 SNA DLC Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
* Profile name
Data link device name
Force disconnect time-out (1-600 seconds)
User-defined maximum I-Field size?
If yes, Max. I-Field size (265-30729)
Max. num of active link stations (1-255)
Number reserved for inbound activation
Number reserved for outbound activation
Local X.25 network address
Receive window count (1-127)
Transmit window count (1-127)
[Entry Fields]
[xdlc]
[x25s0]
[120]
no
[1417]
[100]
[0]
[0]
[3106010760]
[7]
[7]
#
+
#
#
#
#
#
#
#
Secondary and Negotiable Stations
Secondary inactivity time-out (1-255 sec)
[30]
#
Primary and Negotiable Stations
Primary repoll frequency (1-255 seconds)
Primary repoll count (1-255)
[30]
[10]
#
#
Link Recovery Parameters
Retry interval (1-10000 seconds)
Retry limit (0-500 attempts)
[60]
[20]
#
#
Comments
[BOTTOM]
+
F1=Help
F5=Reset
F9=Shell
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
8.3.6.3 Defining the Link Station Profile
A link station provides control function for a single link that connects the local
node to an adjacent node in the SNA network. The link station performs the
following tasks:
•
Controls link activations and deactivations
•
Informs the node CP of link status
•
Communicates with the adjacent link station across the physical medium
Link stations can either call or listen:
•
A calling link station initiates the activation of a link
•
A listening link station waits for a link activation request from a calling link
station
To enter the link station profile information from the first menu of SMIT, select:
Chapter 8. AIX SNA Server/6000
165
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Links
→
X.25
→
X.25 Link Station
→
Add a Profile
Or use the fastpath: smit _snaX25attcmk.
This displays the Add X.25 Link Station Profile screen:
166
RS/0000 X.25 Cookbook
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
* Profile name
Use APPN Control Point′ s XID node ID?
If no, XID node ID
* SNA DLC Profile name
Stop link station on inactivity?
If yes, Inactivity time-out (0-10 minutes)
LU address registration?
If yes, LU Address Registration Profile name
Trace link?
If yes, Trace size
X.25 level
Station type
Adjacent Node Identification Parameters
Verify adjacent node?
Network ID of adjacent node
CP name of adjacent node
XID node ID of adjacent node (LEN node only)
Node type of adjacent node
Link Activation Parameters
Solicit SSCP sessions?
Initiate call when link station is activated?
Virtual circuit type
If permanent,
Logical channel number of PVC (1-4095)
If switched,
Listen name
Remote station X.25 address
X.25 Optional Facilities Profile name
Activate link station at SNA start up?
Activate on demand?
CP-CP sessions supported?
If yes,
Adjacent network node preferred server?
Partner required to support CP-CP sessions?
Initial TG number (0-20)
Restart Parameters
Restart on activation?
Restart on normal deactivation?
Restart on abnormal deactivation?
Transmission Group COS Characteristics
Effective capacity
Cost per connect time
Cost per byte
Security
Propagation delay
User-defined 1
User-defined 2
User-defined 3
F1=Help
F5=Reset
F9=Shell
[Entry Fields]
[xlink]
yes
[07100123]
[xdlc]
no
[0]
no
[]
no
long
1984
secondary
no
[]
[]
[*]
learn
+
+
+
#
+
+
+
+
+
+
+
+
yes
yes
switched
+
+
+
[1]
#
[IBMQLLC]
[3106001984]
[xfacs]
no
no
no
#
+
+
+
+
no
no
[0]
+
+
no
no
no
+
+
+
#
[9600]
#
[128]
#
[128]
#
public_switched_networ> +
packet_switched_networ> +
[128]
#
[128]
#
[128]
#
Comments
[BOTTOM]
Add X.25 Link Station Profile
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Chapter 8. AIX SNA Server/6000
167
Here we have defined:
Use APPN Control Point′s XID node ID?
Determines if the link station is controlled by the node′s APPN CP. If
specifying no, you must specify the XID node ID for the PU
represented by this link station.
XID node ID:
If connecting to a host over a switched connection, enter a value to
support the LU definitions. The value should consist of the IDBLK= (a
three digit hexadecimal) and IDNUM= (a five digit hexadecimal) entries
in the VTAM PU definition.
Stop link station on inactivity:
Specifies whether SNA Server/6000 stops the link station when there
is no traffic on the links for a specified period of time. This choice
can affect system performance, as each open link station uses system
resources.
LU address registration?
Used to indicate if generic LU addresses are registered to this link
station. Generic SNA is used to create special SNA functions that are
not available from SNA Server/6000.
X.25 level:
Indicates, by date, the release of the CCITT X.25 Recommendation
that is supported. SNA Server/6000 V2.1 currently only supports 1980
and 1984, although the X.25 LPP also supports 1988.
Adjacent Node Identification Parameters:
This set of fields enables you to identify the adjacent node to which
this link station profile provides a link.
Link Activation Parameters:
This set of fields describes the behavior of the link station within the
network.
Listen name:
Specifies the name configured in the routing table for routing
incoming calls to Qualified Logical Link Control (QLLC).
Transmission Group COS Characteristics:
This set of fields shows adapter-specific settings for the
communications devices used by this link station. You can, however,
override these settings and specify a nonstandard COS or set of TG
characteristics for a link station by changing the values displayed in
these fields.
To specify non-standard characteristics for a series of link stations or
for specialized communications adapters, you should consider
changing the SNA Server/6000 adapter definition for the
communications device in question.
8.3.6.4 Defining X.25 Optional Facilities Profile
This enables you to specify optional facilities, services and restrictions for X.25
link stations.
168
RS/0000 X.25 Cookbook
Several different X.25 link stations can share the same X.25 optional facilities
profile, so you could specify a set of customized X.25 functions in a single profile
and then apply it to an array of X.25 link stations.
To enter the X.25 optional facilities profile information from the first menu of
SMIT, select:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Links
→
X.25
→
X.25 Optional Facilities
→
Add a Profile
Or use the fastpath: smit _snaX25optsmk.
This displays the Add X.25 Optional Facilities Profile screen:
Add X.25 Optional Facilities Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
* Profile name
Throughput class for received data
Throughput class for transmitted data
Closed user group?
If yes, Index to closed group
Closed user group outgoing access?
Network user identification?
If yes,
Network user ID name
Network user ID in hex?
Reverse charging?
RPOA?
If yes, Data network ID codes
Packet size for received data
Packet size for transmitted data
[Entry Fields]
[xfacs]
9600
9600
no
[0]
no
no
[]
no
no
no
[]
128
128
Comments
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
+
+
+
#
+
+
+
+
+
+
+
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
8.3.6.5 Defining the LU 2 Session Profile
The session profile describes the characteristics of a dependent LU 1, 2 or 3.
Each type of LU on the local node must be defined to SNA Server/6000 in a
session profile. SNA Server/6000 uses this information to process inbound link
requests for the local LU that come from remote hosts or peer systems.
To enter the LU 2 session profile information from the first menu of SMIT, select:
Chapter 8. AIX SNA Server/6000
169
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Sessions
→
LU 2
→
Add a Profile
Or use the fastpath: smit _snasess2mk.
This displays the Add LU 2 Session Profile screen:
Add LU 2 Session Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
[xsess02]
[S4080502]
[2]
* Profile name
Local LU name
* Local LU address (1-255)
System services control point
(SSCP) ID (*, 0-65535)
Link Station Profile name
Network name
Remote LU name
Maximum number of rows
Maximum number of columns
[*]
[xlink]
[]
[]
[24]
[80]
Comments
F1=Help
F5=Reset
F9=Shell
#
+
#
#
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Here we have defined:
Local LU name:
If you are connecting to a host system, the Local LU name is the
assigned name of the resource found in the VTAM LU definition
statement.
Local LU address:
This is the address that remote systems use as the destination
address when they send information to the local LU. On a VTAM
system, the local LU address is defined by the LOCADDR= keyword in
the VTAM LU definition statement.
SSCP ID:
This is the ID of the System Services Control Point (SSCP) of the host
system that controls this LU in the SNA network. This value should be
in decimal . The system uses this value to generate a four-digit
hexadecimal value that corresponds to the SSCP ID= parameter in the
VTAM START statement on the host.
If you require that any host be able to initiate sessions with this LU,
leave it as the default value of * (an asterisk). That way, any host
170
RS/0000 X.25 Cookbook
whose local LU address matches that given in this profile, can initiate
sessions.
Maximum number of rows:
The maximum number of displayed rows that the LU should permit. If
this is smaller than the number of lines of output that the host
expects, SNA Server/6000 rejects bind requests with this LU. VTAM
requires a screen size of 24 rows; using a value less than 24 can
cause a VTAM error.
Maximum number of columns:
The maximum number of displayed columns that the LU should
permit. If this is different to the number of lines of output that the
host expects; some hosts can reject bind requests with this LU.
VTAM requires a screen size of 80 columns; using a value less than
80 can cause a VTAM error.
8.3.6.6 Defining the LU 3 Session Profile
To enter the LU 3 Session Profile information from the first menu of SMIT, select:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Sessions
→
LU 3
→
Add a Profile
Or use the fastpath: smit _snasess3mk.
This displays the Add LU 3 Session Profile screen:
Add LU 3 Session Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
[xsess09]
[S4080509]
[9]
* Profile name
Local LU name
* Local LU address (1-255)
System services control point
(SSCP) ID (*, 0-65535)
Link Station Profile name
Network name
Remote LU name
Maximum number of rows
Maximum number of columns
[*]
[xlink]
[]
[]
[24]
[80]
Comments
F1=Help
F5=Reset
F9=Shell
#
+
#
#
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Chapter 8. AIX SNA Server/6000
171
Here we have defined:
Local LU name:
If you are connecting to a host system, the Local LU name is the
assigned name of the resource found in the VTAM LU definition
statement.
Local LU address:
This is the address that remote systems use as the destination
address when they send information to the local LU. On a VTAM
system, the local LU address is defined by the LOCADDR= keyword in
the VTAM LU definition statement.
SSCP ID:
This is the ID of the System Services Control Point (SSCP) of the host
system that controls this LU in the SNA network. This value should
be in decimal . The system uses this value to generate a four-digit
hexadecimal value that corresponds to the SSCP ID= parameter in the
VTAM START statement on the host.
If you require that any host be able to initiate sessions with this LU,
leave it as the default value of * (an asterisk). That way, any host
whose local LU address matches that given in this profile can initiate
sessions.
Maximum number of rows:
The maximum number of displayed rows that the LU should permit. If
this is smaller than the number of lines of output that the host
expects, SNA Server/6000 rejects bind requests with this LU. VTAM
requires a screen size of 24 rows; using a value less than 24 can
cause a VTAM error.
Maximum number of columns:
The maximum number of displayed columns that the LU should
permit. If this is different to the number of lines of output that the
host expects, some hosts can reject bind requests with this LU.
VTAM requires a screen size of 80 columns; using a value less than
80 can cause a VTAM error.
8.3.7 Verifying SNA Profiles
After you have created or modified configuration profiles, they remain in a
working database. They are not used by SNA Server/6000 until you verify and
promote them to the committed database that SNA Server/6000 uses when it is
running.
In addition, you must choose to update the existing configuration database when
you verify profiles. If verification is successful, the verified profiles can be moved
to the committed database.
The following update options are available when you verify the configuration
database:
No update
Profiles are verified, but the configuration database is not updated.
Normal update
This can only be performed when the SNA Server/6000 is not active.
Following a successful normal update, configuration profiles are used
by SNA Server/6000 when it is next started.
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RS/0000 X.25 Cookbook
Dynamic update
This promotes profiles to the committed database while SNA
Server/6000 is running. If this option is used while the server is not
running, a normal update is performed.
Dynamic updates affect any new SNA Server/6000 control structures
that are initiated following the update. Resources that were already
active prior to the update will continue to use control structures that
were created prior to the update. For an active resource to use
updated information, you must stop and restart the resource.
Dynamic update modifies the Local LU (also Partner LU and Mode
Profiles if using LU 6.2) only if there are no active sessions using
these profiles. If there is an active session using a profile, the update
for that profile does not take effect until you restart SNA Server/6000,
or until you stop any sessions using the profile and perform another
update.
The following profiles are not updated until SNA Server/6000 is
restarted:
•
•
•
•
SNA node
Control point
SNA DLC
Link station that uses a new SNA DLC
To verify the SNA profiles from the first menu of the SMIT interface, select:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Verify Configuration Profiles
Or use the fastpath: smit verifysna.
This displays the Verify Configuration Profiles screen:
Chapter 8. AIX SNA Server/6000
173
Verify Configuration Profiles
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Update action if verification successful
If normal_update or dynamic_update,
Backup file for committed database
Backup security file for committed database
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
[Entry Fields]
none
+
[]
[]
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
The verification checks your local SNA Server/6000 profile database for
inconsistencies to ensure that all system profiles referred to exist in the
database and that their values do not conflict. Only profiles that exist on the
local system are verified for syntax and consistency.
8.3.8 Starting SNA Server/6000 Server
Before any application, such as HCON, can make use of SNA Server/6000, the
SNA server must be running or active .
You can use operator commands to start SNA Server/6000, link stations and LU
sessions. You can also use several configuration options to control starting SNA
Server/6000 resources. In practice, resources can start in several different ways:
•
Link stations can be configured to start when SNA Server/6000 starts.
•
SNA Server/6000 starts automatically if you start a link station when SNA
Server/6000 is not already active.
•
Starting the link station also causes the session to start if the link station is
associated with a dependent LU and is configured to solicit SSCP sessions.
If necessary, the server can be started from SMIT by selecting:
Communications Applications and Services
→
SNA Server/6000
→
Manage SNA Resources
→
Start SNA Resources
→
Start SNA
Alternatively, from the command line, you could enter:
# sna -start
# sna -s
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RS/0000 X.25 Cookbook
or
8.3.9 Starting SNA Server/6000 Link Station
To start a link station from SMIT, use:
Communications Applications and Services
→
SNA Server/6000
→
Manage SNA Resources
→
Start SNA Resources
→
Start an SNA Link Station
Alternatively, from the command line, you could enter:
# sna -start l -p<link station profile name>
# sna -s l -p<link station profile name>
or
8.3.10 Listing Current Status of SNA Server/6000
To show the current status of the SNA server from the SMIT interface, use:
Communications Applications and Services
→
SNA Server/6000
→
Manage SNA Resources
→
Display SNA Resources
Or use the fastpath: smit _snastatserv.
This displays the following screen:
Display SNA Resources
Move cursor to desired item and press Enter.
Display
Display
Display
Display
Display
Display
Display
the Status of SNA
SNA Global Information
Session Information
Active Link Information
APPN Topology Database
APPN Directory Database
SNA Gateway Information
F1=Help
F9=Shell
F2=Refresh
F10=Exit
F3=Cancel
Enter=Do
F8=Image
Then select the desired resource.
Alternatively, status information about SNA can be obtained using the following
command:
# lssrc -s sna
Chapter 8. AIX SNA Server/6000
175
To display more status information including SNA Server/6000, sessions, links,
global information about the local directory and topology databases, use the
commands with the appropriate options:
# sna -displayr
# sna -d
See AIX SNA Server/6000: Command Reference for the available options.
8.4 3270 Host Connection Program/6000
The AIX 3270 Host Connection Program/6000 (HCON) is a software package that
allows a RISC System/6000 to communicate with one or more IBM System/390
computer systems.
8.4.1 Overview
HCON operates in sessions , periods of interaction with a host computer. There
can be display sessions and printer sessions.
A printer session prints files from the host to a local printer or stores printable
files on the local system.
At the beginning of a display session, the emulator acts as if you have started a
3278/79 screen. From this display session, you can run commands and
applications interactively or perform file transfers.
You can also write programs that communicate with the mainframe host using
High-Level Language Application Programming Interface (HLLAPI).
Before you can use HCON, someone with root user authority must register you
as an HCON user. Next, you must create at least one session profile. This
specifies parameters for the emulator sessions, such as:
•
Type of host
•
Emulation type (display or printer)
•
Mode of connection to the host
•
Local printer name (if a printer session)
The smit hcon or the mkhconu commands may be used to add a new HCON user.
Each user of HCON can have a maximum of 26 sessions, each allowing one or
more simultaneous invocations of HCON to communicate with one or more hosts
using different session characteristics and communication protocols.
Session profiles can be created with the smit hcon or mkhcons commands.
The following list is a classification of HCON commands:
1. Setting up HCON:
startsrc -s hcon Starts the hcondmn daemon.
2. Working with HCON users:
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RS/0000 X.25 Cookbook
mkhconu
Registers HCON users.
lshconu
Lists HCON users.
rmhconu
Removes an HCON user.
3. Working with session profiles:
mkhcons
Creates an HCON session profile.
lshcons
Lists the characteristics of a session.
lshconp
Lists all of a user′s session profiles.
chhcons
Changes a session profile.
rmhcons
Removes a session profile.
4. Working with HCON session:
e789 n
Starts one or more specified HCON sessions.
e789cln
Removes IPC resources and HCON processes left over from one
or more abnormally terminated sessions. This will also terminate
all other active sessions for the user issuing this command.
fxfer
Implicit file transfers between the RISC System/6000 and the host
(you can also use hconutil for a full-screen interface).
5. The hconutil command:
Provides a menu which allows the creation of a binary color definition table,
a binary keyboard definition table, explicit file transfer, logon/logoff facilities
and access to the genprof command used to create/modify automatic logon
profiles.
See the Commands Reference RISC System/6000 for more information about
HCON commands.
8.4.2 Setup and Use of 3270 Host Connection Program/6000
Once we have set up all the related SNA Server/6000 profiles, we will follow
these steps to start our connection:
Setup and Use of 3270 HCON/6000
1. Define valid HCON users:
smit mkhconu
2. Define HCON SNA display sessions:
smit mkhcons_st
3. Start an HCON session:
e789 Session_Name
8.4.2.1 Defining HCON Users
First, we add a user named edgar as a valid HCON user:
# smit mkhconu
Add HCON User
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* AIX LOGIN name
[Entry Fields]
[edgar]
Chapter 8. AIX SNA Server/6000
177
8.4.2.2 Defining HCON SNA Sessions
Next, we define a session for user edgar. A letter a will be assigned to uniquely
identify this session. We also specify the SNA connection profile, xsess02, that is
used for this session.
# smit mkhcons_st
Add SNA Display Session
Type or select a value for the entry field.
Press Enter AFTER making all desired changes.
[Entry Fields]
[edgar]
* HCON USER name
+
Add SNA Display Session
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
HCON user name
SESSION name
Session USE
* SNA Profile
COUNTRY
* KEYBOARD table
* COLOR table
* File used by SAVES key
* File used by REPLS key
Host TYPE
Host LOGIN ID
Autolog NODE ID
Autolog TRACE
Autolog TIMEOUT (seconds)
[MORE...5]
F1=Help
F5=Undo
F9=Shell
F2=Refresh
F6=Command
F10=Exit
[Entry Fields]
edgar
a
[X.25 CONNECTION]
[xsess02]
United States
[/usr/lib/hcon/e789_ktb>
[/usr/lib/hcon/e789_ctb>
[/u/edgar/e789_saves]
[/u/edgar/e789_repls]
CMS
[]
[]
no
[0]
F3=Cancel
F7=Edit
Enter=Do
+
+
+
+
+
F4=List
F8=Image
8.4.2.3 Starting a HCON Session
Now, start a 3270 session with the e789 command:
# e789 a
The letter a is the name of the session we just have created for user edgar.
8.4.3 SNA Problems
It can be very difficult for a novice to determine where problems lie in SNA
configurations. Section 9.9, “Diagnosing SNA Server Problems on AIX V4” on
page 194, contains information on the problem determination procedures that
should be followed to help speed up resolution.
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RS/0000 X.25 Cookbook
#
8.4.4 HCON Problems
If the file transfer times out on a System/390 host, the emulator screen will
display the message 0789-114.
One of the reasons this can occur is that the PSERVIC field of the MODEENT
macro has not been set correctly for HCON. (See the VTAM listings given in
8.3.3, “Getting Host Definitions” on page 160 to find the format.) If it has been
set correctly, check that the log mode table has been refreshed since changing
the PSERVIC value.
AIX Communications Concepts and Procedures contains more information on
troubleshooting with HCON.
Chapter 8. AIX SNA Server/6000
179
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RS/0000 X.25 Cookbook
Chapter 9. X.25 Problem Determination
This chapter contains information that is intended to be helpful, accurate and
useful as a guide of how to accomplish a given system task. The provided
explanations, techniques and procedures have been reviewed for technical
accuracy and applicability but have not been tested in every possible
environment or situation. Normal precautions should be taken in adopting these
same techniques and procedures, because as product and system interfaces
change, so would the use of this information.
9.1 X.25 Problem Diagnosis
Before investigating any problem, ensure that X.25 communications are set up
correctly. These commands may help diagnose the problem:
•
•
•
•
•
•
The x25mon command
The xtalk command
The lsx25 command
The x25status command
The sx25debug command
X.25 clear and reset codes (See Appendix D, “CCITT Causes and
Diagnostics” on page 269.)
See the following for further discussion of X.25 problems and solutions:
•
•
•
•
•
•
•
•
•
•
9.2, “Diagnosing Problems with Connecting to the X.25 Network”
9.3, “Diagnosing Problems with Making an Outgoing X.25 Call” on page 182
9.4, “Diagnosing Problems with Receiving an Incoming X.25 Call” on
page 183
9.5, “Diagnosing X.25 Packet Problems” on page 183
9.6, “Diagnosing X.25 Command Problems” on page 184
9.7, “Diagnosing xtalk Problems” on page 185
9.8, “Diagnosing TCP/IP Problems” on page 191
9.9, “Diagnosing SNA Server Problems on AIX V4” on page 194
9.12, “Collecting Information for Resolution of X.25 Problems” on page 206
9.13, “How to Resolve an X.25 ′Device Busy′ Condition” on page 207
9.2 Diagnosing Problems with Connecting to the X.25 Network
Problem
When adding a port, adapter or driver, the add fails due to:
A device is already configured at the specified location.
Suggestion
The lsx25 command will show how the X.25 system is configured.
Other software might be configured to use a given adapter, in which
case the adapter would appear in the configuration listing, but there
would be no adapter driver.
Problem
Attempts to connect an X.25 port fail when making the port using
mksx25 or through SMIT. The physical and the frame layers remain
down. The x25mon command shows that there is no line activity.
 Copyright IBM Corp. 1996
181
Suggestions
•
The cable is loose or missing.
•
There is no carrier (DCD or RLSD) from the network terminating
unit (NTU).
•
There is a cabling problem such as an extra null.
•
The X.25 adapter is not seated correctly.
Problem
Attempts to connect an X.25 port fail. The physical layer is
established for several seconds, as shown by the lights on the NTU,
but then goes down again. The x25mon command indicates that there
is no line activity.
Suggestions
•
The cable is loose, causing the clock pin to be disconnected.
•
The X.25 adapter is expecting a clock signal and not receiving
one. Adjust the NTU to provide clocking.
Problem
Attempts to connect an X.25 port fail. The physical layer is connected,
but the frame layer fails to come up. The x25mon command monitoring
the frame layer may show a string of SABMs.
Suggestions
•
The type of line attribute is DCE rather than DTE for this X.25
adapter. Ensure that the DTE/DCE switching configured in SMIT is
suitable for the devices being attached.
•
The connection mode attribute is set incorrectly. Use SMIT to
change it.
9.3 Diagnosing Problems with Making an Outgoing X.25 Call
Problem
Incoming calls are arriving, but outgoing calls cannot be made on a
switched virtual circuit (SVC).
Suggestions
•
The configuration of the SVC logical channel numbers is incorrect.
Check your network subscription and use SMIT to check the
network attributes.
•
Use SMIT to check that outgoing calls are allowed.
Problem
A call is being cleared with a cause code from 1 to 127.
Suggestion
Either the network or the adapter is clearing the call. The diagnostic
code gives details of why the call is being cleared. Common causes
are that the network user address (NUA) is not known, the X.25 line is
not connected or unsupported optional facilities have been requested.
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RS/0000 X.25 Cookbook
Note: Cause codes 80 to FF are set by SNA. See 9.7.2, “X.25
Protocol Problems” on page 186.
9.4 Diagnosing Problems with Receiving an Incoming X.25 Call
Problem
The x25mon command indicates that an incoming call has arrived at
the adapter, but it is not being routed to the application that is
running.
Suggestions
•
If the call is being cleared with cause 0 and diagnostic 0, it may
be that the application is not listening to a name in the routing list
that matches the incoming call. There may be another name in
the routing list that is a better match to the call and has reject (R)
specified as the action. The routing list is used only by COMIO
applications.
•
The incoming call may have requested an optional facility that is
not allowed by the current configuration.
•
The incoming call may have arrived on an invalid logical channel.
Check your network subscription and the network configuration
attributes in your SMIT configuration.
•
Use SMIT to check that incoming calls are allowed.
•
Check the cause and diagnostic codes with the standard list of
codes and any network-specific codes.
•
A different application may be listening to criteria that are a better
match those which your application is listening. Check for another
program using the X.25 adapter.
9.5 Diagnosing X.25 Packet Problems
Problem
Whenever a packet is sent on a permanent virtual circuit (PVC), the
network sends a clear-indication packet.
Suggestion
The logical channel number ranges are set incorrectly. Check your
network subscription and your SMIT configuration.
Problem
When sending a data packet with the D-bit set on a switched virtual
circuit (SVC), a reset-request packet is sent instead.
Suggestion
The intention to use D-bits must be made clear when the call is
originally established, either in the call-request packet or in the
call-accepted packet.
Problem
When sending a data packet with the D-bit set on a permanent virtual
circuit (PVC), a reset packet is sent instead.
Chapter 9. X.25 Problem Determination
183
Suggestion
Use SMIT to configure the PVC to use D-bits.
Problem
When sending an interrupt packet with more than one byte of user
data, a reset packet is sent instead.
Suggestion
The 1980 version of X.25 supports exactly one byte of user data in the
interrupt packet. The 1984 and 1988 versions support up to 32 bytes.
Check the subscription and the value of the support attribute in SMIT.
Problem
When sending large packets on slow lines, the link sometimes gets
restarted.
Suggestion
The CCITT timer, T1, may have expired. Use SMIT to increase the
value of the attribute, or use smaller packets.
Problem
While trying to connect the line, the x25mon command shows reject
packets coming from the DCE instead of restart packets.
Suggestion
The most likely cause is that the packet modulo parameter you have
choosen is not appropriate and must be changed with smit
x25str_mp_csp_p_sel.
9.6 Diagnosing X.25 Command Problems
Problem
Attempts to start up the x25mon command on the X.25 port fail.
Suggestion
Only root may start the X.25 monitoring.
Problem
The xmanage, xcomms and xmonitor commands are not in Version 4.
Suggestion
These commands are not shipped with the V4 LPP. The x25mon
command replaces xmonitor.
Problem
None of the X.25 commands get past the title panel.
Suggestion
Use the echo $TERM command to find out your terminal-type setting
and make sure that it matches your actual terminal type.
Problem
The number of virtual circuits cannot be configured past an upper
limit.
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RS/0000 X.25 Cookbook
Suggestion
The maximum number on VCs supported depends on the license of
the product that was purchased.
Problem
COMIO emulation ports fail to configure on available x25 ports
(sx25a n ).
Suggestion
AIX V3 users must ensure that their Portable Streams Environment
has been updated to the latest available PTF level.
9.7 Diagnosing xtalk Problems
You can use xtalk as a tool to diagnose COMIO problems. Common problems
when using xtalk:
Problem
You may get ERROR 22 when using xtalk.
You cannot use the Talk function because no X.25 adapters have been
configured
Suggestion
You must configure a port first.
Problem
Sometimes you get this message:
The call has been cleared with cause 00 and diagnostic 81
Suggestion
Please check that the listening machine (the DCE one) has xtalk
running. Start xtalk first on the DCE machine before calling.
9.7.1 Device Driver Problems
You have a device driver problem when xtalk displays a message starting with a
CIO status such as this one:
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
ERROR 110 │
├──────────────────────────────────────────────────────────────────────────────┤
│ CIO Status 68 - X25_NAME_USED
│
│ The name is already being listened to.
│
│
│
├─────────────────────────────────────────────────────────────┬────────────────┤
│
│ Esc = Cancel │
└─────────────────────────────────────────────────────────────┴────────────────┘
These messages, corresponding to return codes of the device driver, are listed
in Appendix G, “CIO and X.25 Device Driver Error Codes” on page 293. Since
you have already tested the connection to the network, the errors that are most
likely to appear are those related to the routing table:
CIO Status 68 - X25_NAME_USED
The name is already being listened to.
Another copy of xtalk is probably running in
the background and listening to IBMXTALK.
Chapter 9. X.25 Problem Determination
185
Remember to always use QUIT to leave
xtalk (and not F3).
CIO Status 77 - X25_TABLE
Could not update routing list. A copy of
xroute is probably still running, or a lock file
xroute.lck has been left in /etc/locks.
CIO Status 73 - X25_NO_NAME
There is no such name in the routing list.
The -l parameter does not match an entry
in the routing list.
Two other problems are also related to the routing:
•
The call has been cleared with cause 00 and diagnostic 00.
This means that the call has reached the remote system but has not been
transmitted to an application. Either the application ( xtalk) is not loaded, it
has not been started with the -l IBMXTALK flag or the IBMXTALK entry in
the routing table does not exist or does not contain a CUD matching the one
in the incoming call packet (FD).
•
The call has been cleared with cause 00 and diagnostic F4.
This is a diagnostic generated by xtalk on the called DTE meaning that xtalk
received the call but was not ready to accept it (not on the main menu).
9.7.2 X.25 Protocol Problems
If you get a message like the following, you have an X.25 protocol problem:
┌──────────────────────────────────────────────────────────────────────────────┐
│X.25 Communications XTALK
INFORMATION 006 │
├──────────────────────────────────────────────────────────────────────────────┤
│ The call has been cleared with cause 13 and diagnostic 43.
│
│
│
├─────────────────────────────────────────────────────────────┬────────────────┤
│
│ Esc = Cancel │
└─────────────────────────────────────────────────────────────┴────────────────┘
The cause and diagnostic codes reported by xtalk are hexadecimal values
indicating the reason for the problem; x25mon reports decimal values. These
codes may be generated by the local system, the PSDN or the remote DTE and
are explained in Appendix D, “CCITT Causes and Diagnostics” on page 269.
Notes:
186
•
The microcode on the X.25 adapter initially assumes that an incoming call
where the first byte of the Call User Data is greater than 0xC0 is coming from
an SNA system. (All X.25 SNA implementations such as QLLC use such
codes - they are defined in the architecture manuals.) Thus, if the adapter
does not like the incoming call packet for some reason, it will reject the call
using SNA cause and diagnostic codes. (See D.5, “SNA Diagnostic Codes”
on page 271.) SNA codes are only assumed until the application is past the
incoming call, when it is allowed to specify which codes should be used for
the call.
•
If the Call User Data is less than 0xC0, then CCITT cause and diagnostics are
used.
•
Some networks will also generate diagnostic codes which are not in the
standards. A clear packet was generated by the network if its cause code
RS/0000 X.25 Cookbook
was between 0x01 and 0x7F. To interpret codes generated by the network,
you will need to ask your network provider for additional documentation.
9.7.2.1 Normal Virtual Circuit Establishment
In some cases, the information given by the cause and diagnostic codes is
sufficient to determine the nature of the problem and the way to fix it, but often
you will have to look at the x25mon packet trace on both systems to determine
what really happened.
The normal sequence of packets to establish an SVC connection is shown in
Figure 51.
┌─────────┐ Call Request
┌──┬────────┬──┐ Incoming Call
┌────────┐
│
1├───────────────────│ D│
│D ├─────────────────│2
│
│ Calling │
│ C│ PSDN │C │
│ Called │
│ DTE 4│───────────────────┤ E│
│E │─────────────────┤3 DTE │
└─────────┘ Call Connected └──┴────────┴──┘ Call Accepted └────────┘
Figure 51. Establishing a Switched Virtual Circuit
This is what you can see on the traces when the virtual call is established. (The
trace on the calling machine is on the left. The trace on the called machine is on
the right. Only the beginning of each line is shown.):
# x25mon -p -n sx25a0
X.25 Monitor sx25a0
16:11:21 sx25a0 PS 0x0014 CALL..
─Call request─┐
Incoming call
16:11:22 sx25a0 PR 0x0001 CALL...
16:11:27 sx25a0 PS 0x0001 CF CALL
Call accepted
16:11:27 sx25a0 PR 0x0014 CF CALL.. ─connected─┘
1
2
3 4 5
Column one contains a time stamp; column two contains the name of the X.25
attachment used.
Column three contains PS when the packet is sent to the network, PR when it is
received from the network.
Column four contains the logical channel number displayed in hexadecimal. The
calling DTE always uses the highest available logical channel, 20 (14 in hex) in
our case, to establish a call. The DCE always uses the lowest available logical
channel, one in our case, to transmit an incoming call to the called DTE.
The contents of column five tell you the type of packet: CALL for the call request.
or incoming call, CF CALL for the call confirmation packets call accepted and
call connected.
Let us now look at the contents of the call packets. The format is the same for
the different call packets and is described in Figure 52 on page 188:
Chapter 9. X.25 Problem Determination
187
Octets
1
2
3
4
Bits
8
7
6
5
4
3
2
1
┌─────────────────────────┬──────────────────────────┐
│ General format ident. │ Logical channel group │
├─────────────────────────┴──────────────────────────┤
│
Logical Channel Number
│
├────────────────────────────────────────────────────┤
│
Packet type identifier
│
├─────────────────────────┬──────────────────────────┤
│
Called Addr. Length │ Calling Addr. Length
│
├─────────────────────────┴──────────────────────────┤
:
DTE addresses
:
├────────────────────────────────────────────────────┤
│
Facility length
│
├────────────────────────────────────────────────────┤
:
Facilities
:
├────────────────────────────────────────────────────┤
:
CUD
:
└────────────────────────────────────────────────────┘
Figure 52. Call Packet Structure
Calling address length
Called address length
Called NUA
Calling NUA
Facilities length
Facilities
CUD
0 to 15, binary value coded on 4 bits
0 to 15, binary value coded on 4 bits
0 to 15 decimal digits; each digit is coded on 4 bits (BCD
Binary Coded Decimal)
0 to 15 decimal digits; each digit is coded on 4 bits (BCD
Binary Coded Decimal)
0 to 109, binary value coded on one octet (8 bits)
0 to 109 octets; the way to decode this field is explained
in Appendix E, “Facilities” on page 275.
Call user data, up to 16 octets of application-defined data
(up to 128 if the fast select facility has been subscribed
to and has been selected). The CUD is generally used
to identify the protocol being used.
Note: The calling NUA is optional in the call packets. Some networks even
forbid it in the call request packet (the French TRANSPAC network for
example) and generate it automatically in the incoming call packet. In
this case, use smit x25str_mp_csp_g_sel to change the calling address in
the call request packet parameter to forbid.
This is what we get on the trace. (We have now suppressed the beginning of
each line.):
On the calling side:
# x25mon -p -n sx25a0
X.25 Monitor sx25a0
PS 0x0014 CALL
dN la:10 lf:0
PR 0x0014 CF CALL dN la:0 lf:5
ld:1 AA3106010761310601076000FD
ld:0 000502AA420A0A
On the called side:
# x25mon -p -n sx25a0
X.25 Monitor sx25a0
PR 0x0001 CALL
dN la:10 lf:7
PS 0x0001 CF CALL dN la:0 lf:0
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ld:1 AA310601076131060107600702AA0100420A0AFD
ld:0 0000
The information given by the above is the following:
dN
la:
lf:
ld:
No D bit (Delivery confirmation). A dY code would mean that the D bit is
present.
Length of the addresses (called+calling) in octets (decimal)
Length of the facilities
Length of the CUD
The call request can be interpreted like this:
AA
3106010761
3106010760
00
FD
Calling address length 10, called address length 10
Called NUA
Calling NUA
Length of facilities
CUD, used in the routing table entry IBMXTALK to send this call to
xtalk.
If we look now at the incoming call, we see that the network has modified the
packet and has inserted 7 bytes of facilities before the CUD. Using Appendix E,
“Facilities” on page 275, they can be interpreted as follows:
07
02AA
0100
420A0A
Facilities length, 7 octets
Throughput class 9600/9600
Reverse charging or fast select, none selected
Packet size 1024/1024
The receiving DTE can accept these values, negotiate them or reject them by
clearing the call. In our case, they are accepted.
The call accepted packet has an address size of 0, a facilities size of 0 and no
CUD. The call connected packet has facilities only.
9.7.2.2 Virtual Circuit Establishment Problems
The first thing to do to analyze a virtual circuit establishment problem is to use
Appendix D, “CCITT Causes and Diagnostics” on page 269, to understand the
cause and diagnostic codes displayed by xtalk (when they exist), then to look at
the call packet in the trace to check that there is no obvious format problem.
Then you can check for a clear packet on the trace, which should look like this:
..
.
16:33:02 sx25a0 PS 0x0001 CLEAR
c:9
d:114
where c:9 is the cause and d:114 is the diagnostic, both expressed in decimal.
Before going further, let us look at the case where no clear packet shows up in
the trace.
Nothing on the trace: In some cases, xtalk displays a cause and a diagnostic
code, but nothing shows up on the packet trace. This happens when you specify
the use of facilities in the call packet (see 3.7.1, “Facilities Requested by the
DTE” on page 68) and these facilities are either invalid or not enabled in the
device driver. (For further details see 3.7.1, “Facilities Requested by the DTE” on
page 68.) The device driver does not send the call request on the network but
reports the problem to xtalk using the same codes as they would in a clear
packet.
Call is sent but not received by the remote DTE: If the call is hanging and you
can only see a call request packet on the trace, look at the logical channel
number used to make the call (column 4 of the x25mon output). Check with your
Chapter 9. X.25 Problem Determination
189
subscription and make sure that it is not higher than the lowest logical channel
number used for SVCs, plus the number of SVCs subscribed to, minus 1. If
necessary, modify the corresponding parameters in your system after having
terminated all the programs using the X.25 attachment. (See 3.3.4, “Updating the
Number of Virtual Channels” on page 58.)
Incoming call received by the DTE but not acknowledged: If the DTE doesn′ t
answer an incoming call, check the two-way SVC - lowest logical channel
number you have customized and make sure that it is not higher than the one in
your subscription.
Incoming call received, reset packet sent back: If the DTE sends a reset packet
instead of a call accepted when it receives an incoming call, there is probably a
PVC that is assigned in the SVC logical channel range. Check your subscription
and correct the logical channel assignments with smit x25str_mp_csp_g_sel.
Clear packet in the trace: A clear packet can be sent by any of the DTEs or by
the PSDN during the various stages of call establishment:
•
By the PSDN as a response to the call:
┌─────────┐ Call Request
┌──┬────────┬──┐
│
1├───────────────────│ D│
│D │
│ Calling │
│ C│ PSDN │C │
│ DTE 2│───────────────────┤ E│
│E │
└─────────┘ Clear Request
└──┴────────┴──┘
Figure 53. Call Cleared by the DCE
•
By the called DTE as a response to the incoming call:
┌─────────┐ Call Request
┌──┬────────┬──┐ Incoming Call ┌────────┐
│
1├───────────────────│ D│
│D ├─────────────────│2
│
│ Calling │
│ C│ PSDN │C │
│ Called │
│ DTE 4│───────────────────┤ E│
│E │─────────────────┤3 DTE │
└─────────┘ Clear Indication └──┴────────┴──┘ Clear Request └────────┘
Figure 54. Call Cleared by the Remote DTE
•
Or even by the calling DTE as a response to the call confirmation:
┌─────────┐ Call Request
┌──┬────────┬──┐ Incoming Call ┌────────┐
│
1├───────────────────│ D│
│D ├─────────────────│2
│
│ Calling4│───────────────────┤ C│
│C │─────────────────┤3Called │
│ DTE 5├───────────────────│ E│
│E │
│ DTE │
└─────────┘ Clear Request
└──┴────────┴──┘
└────────┘
Figure 55. Call Cleared by the Calling DTE
There are many cause and diagnostic codes:
•
Invalid facility request cause 03
This error may be generated by the attachment, the DCE or the remote DTE.
It may occur even if you have not specified facilities in your call packet, in
which case these are the facilities inserted in the incoming call and call
connected packet by the DCE that are rejected by all of the DTEs.
•
Diagnostics CCITT 65 (0x41) or SNA 228 (0xE4) or 231 (0xE7) mean that the
facility carried by a call packet either:
−
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Does not exist
−
−
−
•
Has been disabled on the RISC System/6000 (see 3.7.1, “Facilities
Requested by the DTE” on page 68)
Has not been subscribed to
Is incompatible with the level of CCITT support (1988)
Diagnostics CCITT 66 (0x42) or SNA 230 (0xE6) mean that the facility
parameters either:
−
−
Are invalid
Are not compatible with the RISC System/6000 X.25 customization:
- Request for a packet size is larger than the maximum
- Request for a throughput class is larger than the default
9.8 Diagnosing TCP/IP Problems
To ease the determination of TCP/IP problems, first suppress any default
gateways you may have. This will avoid routing IP packets to a gateway rather
than using the X.25 attachment.
Also disable the nameserver, if you have one, to avoid the discrepancies with
/etc/hosts.
9.8.1 Preliminary Checks
•
Verify with the host command that the hostname and IP addresses are
correct on both the local and remote systems. If this is not the case, update
/etc/hosts and execute the x25ip command.
•
Verify with smit chinetsx25 that the IP-to-NUA translation table entry for the
remote host is correct. Do the same verification on the remote host.
•
Use netstat -r to verify that there is a route to your remote system. This
route can be either an implied route or a static route.
−
The implied route gives access to all the hosts belonging to the same
network as the attachment. This network is defined by applying either
the default netmask corresponding to the network class or an optional
netmask to the IP address of the attachment. In the netstat output, the
X.25 implied route has a U in the Flags field and xs n in the Interface field.
In our case this is what we got:
Destination
..
.
Gateway
Flags
Refcnt Use Interface
9.3.5
kilix
U
0
181
xs0
This route gives access to all the hosts belonging to the IP network 9.3.5
obtained by applying to fili′s address our netmask 255.255.255.0.
−
Now check the static routes identified by UH in the Flags field and xs n in
the interface field. You should see the remote system X.25 hostname in
the Destination field.
Destination
..
.
filix
Gateway
Flags
Refcnt Use Interface
kilix
UH
0
328
xs0
If an IP address appears in the Destination field, this means that the IP
address that you have entered in the route command cannot be resolved
Chapter 9. X.25 Problem Determination
191
using /etc/hosts. Either delete this route and re-create it using the route
command, or update /etc/hosts.
9.8.2 Testing with ping
After you have done these preliminary tests, start x25mon at the packet level in
one window or session:
# x25mon -f -p -n sx25a0
In another window or session, ping the remote host. If you do not get the
expected result, there are four possible scenarios:
1. No error message, nothing transmitted
2. Error message, nothing transmitted
3. No error message, the trace shows attempts to establish a virtual circuit
4. No error message, data transmitted
No error message, nothing transmitted: You have a gateway that ping used to
send your packets. Verify with netstat -r (not with ifconfig) that the X.25
connection is active. Recheck the static routes and, if necessary, remove and
replace the X.25 routes that have a G-flag in the netstat output (see above).
Error message, nothing transmitted: If the error message is:
sendto: Network is unreachable
Or:
sendto: No route for this host
You have a problem either with the attachment definition or with the route.
If the error message is:
ping: sendto: Can′ t assign requested address
Sendto: The socket name is not available
There is a problem with the x25ip translation table. Change it with smit
chinetsx25 or add a correct entry if necessary with smit mksx25.
If you run the ping command and the output looks similar to:
#ping -c 1 nohostx
PING nohostx: (11.3.5.192): 56 data bytes
0821-069 ping: sendto: The socket name is not available on this system.
ping: wrote nohostx 64 chars, ret=1
----nohostx PING Statistics---1 packets transmitted, 0 packets received, 100% packet loss
the TCP/IP X.25 interface driver could not find nohostx in its X25ip translation
table. Run the x25ip -s command and see if it lists the remote host you are
trying ping. If not, use the procedure described in chapter 7, to add an entry to
the X25ip translation database.
Other TCP/IP debugging tips:
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Check your IP routing table. When configuring IP, you must use a unique network
ID for EVERY interface on your system.
If your ping fails without an error message, examine the ARP table by entering
the following command:
arp -a
You should see a listing similar to this:
foox (11.3.5.165) at
X.25 permanent
archiex (8.3.5.206) at 70700
X.25
rascalx (8.3.5.207) at (incomplete)
b905names.itso.ibm.com (123.22.143.253) at 10:0:5a:c9:28:fe (token ring) 840:b991:
Note: The b905names entry is for token ring and is not relevent for this
example. However, you are likely to see entries for other networks in the
arp table.
The entry for foox is typical for a PVC. (Note the permanent descriptor at the end
of the line.) The entry for archiex is typical for a SVC. This line indicates that the
X.25 call to archiex was completed (the VC exists) and TCP/IP data can be
transmitted between archiex and the local host.
The rascalx line is a typical ARP table entry that does not know the hardware
address for the host (rascalx). This is true for any type of TCP/IP interface driver
that uses the ARP table. If the host shown is reached by way of X.25, it indicates
that the X.25 call was not completed. This implies that an X.25 call packet has
gone out, but the system has not received a response, either to confirm or clear.
This could be the result of a slow network or misconfiguration. If this occurs,
check the X25ip database entry using:
x25ip -s -h <hostname>
The output should look similar to the following:
IP/X.25 Switch Virtual Circuit
IP host name
Remote DTE address
Rcv packet size
Xmit packet size
Rcv window size
Xmit window size
Closed user group index
Closed user group index (outgoing)
RPOA selection
User-defined facilities
Call user data
Configuration
rascalx
55545
cc
Assure that the entry has the correct NUA, packet sizes and so on. If the
parameters are correct, and then use x25mon to trace the outgoing line in more
detail. Use the section in this book on x25mon to interpret the trace.
Attempts to establish a virtual circuit: If you see in the trace a series of call
packets showing unsuccessful attempts to open a virtual circuit, please refer to
9.7.2, “X.25 Protocol Problems” on page 186 for the problem determination
procedure.
Chapter 9. X.25 Problem Determination
193
If the incoming call is rejected by the remote system with the diagnostic 241,
calling address missing, the calling address was not in the translation table.
Add it and use x25ip on the remote host to regenerate it.
Data sent to the remote host but nothing received: In this case, a virtual circuit
is established and data packets are sent to the remote host, but the remote host
does not reply. The packets are correctly transmitted to the remote host, but the
remote host IP address they carry does not match the actual IP address of the
remote host. Configure the IP addresses so that both the local and remote host
agree. This can be done on either host.
9.8.3 Function Keys not Working Properly
When using telnet or rlogin over X.25, the remote system does not always
respond correctly to use of the function keys, especially if using Esc-1 instead of
F1. The ESCDELAY environment variable controls the timeout period after which
the screen handling applications will consider the Esc key to be separate from
the following 1. The ESCDELAY variable only works if the applications are written
to Curses or Extended Curses. When running over X.25, the Esc key is often put
by IP into a separate data packet from the following key. The gap between the
two data packets on the receiving system is often farther apart than the default
timeout. The default value of ESCDELAY (or if it is not set at all) is 500.
Try setting ESCDELAY to a very high value as follows:
1. Insert the following in the /etc/environment file
ESCDELAY=5000
2. Log completely out of the system, and then log back in to make sure the new
ESCDELAY value is set.
3. Verify via the following command:
echo $ESCDELAY
Once your test is completed, remember to either adjust the value down to a
more reasonable value (between 1000 and 2000) or, if your problem is not
resolved, remove this line completely from the /etc/environment file. If setting
this ESCDELAY parameter does not fix your problem, then your application is not
written to extended curses and the application must be modified to await the
entire escape sequence. For example, the AIX SMIT application is written to
curses, but it will work over a slow network regardless of ESCDELAY because
SMIT was written to wait indefinitely for the entire escape sequence. Thus, even
though the iptrace tool clearly shows the separation of the Esc and the
remainder of the escape sequence, the escape keys work correctly in SMIT.
9.9 Diagnosing SNA Server Problems on AIX V4
When you experience a problem with SNA Server on the RISC System/6000,
certain information is necessary to investigate your problem. The purpose of this
section is to inform you of what information is available and how to create that
information. The more information that is available when you report the problem,
the quicker the problem can be resolved.
All of the traces that are generated are memory traces. It is therefore necessary
to turn off tracing to ensure that the last buffer gets written to the trace file.
Stopping SNA will also flush the buffers. The logs can then be formatted.
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It is also very important that all information be collected at the same time. Use
the date command to ensure that all machines are synchronized. This is
important for determining the timing of events in the traces and logs.
When a problem is reported, there are certain things that you should be
prepared to send to the support center. The information should be put into a
single directory. That directory should either be sent to the support center in
compressed tar format on a diskette or tape, or uploaded to a mainframe (using
binary format) and sent to the support center over the network.
One problem we encountered with SNA was when we tried to start linkstation,
we got the following error :
0105-2920 Start link station cannot find the specified remote station
This is because the machines are not configured as one DTE and the other as
DCE. To do this, please follow the procedure in Chapter 3.3.5 to Change/Show
Packet Parameters, and be sure that the Type of line parameter shows DTE to
one machine, and DCE to the other. The other thing to check is the SNA
linkstations; it is important that one is call and one is listen. In this case, the DCE
X.25 machine was the listen SNA linkstation. This was discovered by running a
x25mon trace which is below:
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
FR
PR
FS
PS
FR
PR
PS
FS
FR
FS
PR
PS
FR
0x0000
0x0009
0x0000
0x0009
0x0000
0x0009
0x0009
0x0000
0x0000
0x0000
0x0009
0x0009
0x0000
INFO
CALL
INFO
CLEAR
INFO
CF CLEAR
CALL
INFO
INFO
INFO
CLEAR
CF CLEAR
RR
a:3
dN
a:1
c:0
a:3
p:0 ns:0 nr:1 10090BAA3106000002310600000100CB
la:10 lf:0 ld:1 AA3106000002310600000100CB
p:0 ns:1 nr:1 1009130081
d:129
p:0 ns:1 nr:2 100917
dN
a:1
a:3
a:1
c:0
la:10 lf:0 ld:1 AA3106000001310600000200CB
p:0 ns:2 nr:2 10090BAA3106000001310600000200CB
p:0 ns:2 nr:3 1009130081
p:0 ns:3 nr:3 100917
d:129
a:1 p:0 nr:4
Below is a checklist which may help, should you see the above error:
Table 13. SNA Problem Checklist
System 1
System 2
DCE
DTE
Secondary
Primary
Listen SNA Linkstation
Call SNA Linkststation
Unique NUA
Unique NUA
Always have the ″listening linkstation″ in starting state before starting the call
linkstation.
Chapter 9. X.25 Problem Determination
195
9.10 Basic Information Required
By default, all SNA Server/6000 failure information is captured in the SNA
Server/6000 service log. The exception to this is if you have redirected SNA
Server/6000 failure data to the system event trace log and the trcstop command
was used to stop system tracing. (This stops the writing of SNA Server/6000
trace information to the system event trace log, along with other AIX trace
information.)
When collecting your data, only information pertaining to your problem should be
captured in the traces and logs.
If you need to re-create logs for a particular problem, perform the following:
•
Before re-creating the problem, remove all instances of the following logs:
−
−
−
−
Service log
All trace logs
Failure log
Ensure the system error log is also clear
•
Activate data collection
•
Reproduce the problem
•
Deactivate data collection
Note: When collecting data for a problem, make sure that all traces are from the
same problem occurrence and not from different occurrences of the same
problem.
If the problem involves multiple RISC System/6000s, ensure that the traces are
cleared for each one.
9.10.1 Problem Definition
One of the most important things required is a clear definition of the problem.
This should be included in a file called README on the media. This file should
also include a list of the files on the media and a brief description of those files.
Be sure to answer the following questions in the problem description:
1. What happened?
2. Can it be reproduced? If so, list the steps to re-create it.
3. What were the exact error messages that were generated? This should
include messages from all machines involved (other RISC Systems, AS/400,
PS/2, mainframes).
4. What release of the SNA Server/6000 program is active and committed?
5. What release of the AIX operating system is active and committed?
6. What release of the HCON program is active and committed?
7. What fixes have been applied to the system?
8. Has it ever worked? If so, what changes occurred before it stopped working?
9. Get SNA trace of the problem and package up using the
/usr/lpp/sna/bin/getsnapd command. This produces the following file:
/var/sna/pd.tar.Z
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9.10.2 Profiles
You should always provide your profiles when you have a problem. This can be
done using SMIT as follows:
Communications Applications and Services
→
SNA Server/6000
→
Configure SNA Profiles
→
Advanced Configuration
→
Export Configuration Profiles
Alternatively, you could use the command:
# exportsna -A -f <FullPathName>
Table 14 lists the traces that would need to be provided to the support
organization that you are dealing with when you report the problem. They are
listed by problem category.
Table 14 (Page 1 of 2). Information to Gather for Specific Problem Categories
Problem Category
Information Needed
Transaction Programming API
Calls (such as open, close, read,
write)
SNA Server/6000 failure log
Link station trace
SNA Server/6000 configuration profiles
SNA API trace
AIX system error log
Unable to activate a session
SNA Server/6000 failure log
Link station trace
SNA Server/6000 configuration profiles
AIX system error log
Configuration
SNA Server/6000 failure log
SNA Server/6000 configuration profiles
System crash
SNA Server/6000 failure log
AIX system error log
Kernel dump and running kernel (/unix)
Information summary file from running crash
Core dump
Core file in /usr/lpp/sna/bin
Executable file that caused the dump
Generic SNA API or generic
device driver (GDD)
Generic SNA API trace
Link station trace
SNA Server/6000 failure log
AIX system error log
SNA Server/6000 hang (system
does not respond to input)
SNA Server/6000 failure log
Link station trace
SNA API trace
Kernel dump and running kernel (/unix)
AIX system error log
/etc/drivers/sna_sysx when using emergency fixes
Install
AIX system error log
linktest command
SNA Server/6000 failure log
AIX system error log
Chapter 9. X.25 Problem Determination
197
Table 14 (Page 2 of 2). Information to Gather for Specific Problem Categories
Problem Category
Information Needed
Logical unit flows (such as
ACTLU, DACTLU, BIND, UNBIND)
SNA Server/6000 failure log
Link station trace
SNA Server/6000 configuration profiles
SNA API trace
AIX system error log
LU 0 primary LU
LU 0 API trace (primary)
LU 0 server trace
SNA Server/6000 configuration profiles
AIX system error log
LU 0 secondary LU
LU 0 API trace (secondary)
LU 0 server trace
Generic SNA API trace
Link station trace
SNA Server/6000 failure log
SNA Server/6000 configuration profiles
AIX system error log
Link flows (such as XID
exchanges)
SNA Server/6000 failure log
Link station trace
SNA Server/6000 configuration profiles
AIX system error log
Starting or stopping link stations
SNA Server/6000 failure log
Link station trace
SNA Server/6000 configuration profiles
AIX system error log
Starting and stopping sessions
SNA Server/6000 failure log
Link station trace
SNA Server/6000 configuration profiles
AIX system error log
If you are using HCON, you may also be required to provide HCON trace
information.
9.10.3 SNA Server/6000 Traces
There are two main types of traces that can be produced with SNA Server/6000.
They are described in the following sections.
9.10.3.1 Link Station Traces
Link station traces show all data sent or received by the RISC System/6000 at
the Data Link Control layer from the time the trace is turned on. (To include the
XID exchanges that start the link station, the trace should be turned on before
the link station is activated.)
After a link station trace is activated for a specific link station, the system
generates a log of all link activities:
•
•
•
•
•
Link activity timeouts
Link opens
Send data
Receive data
Link closes
You can use link station traces to examine the flow of SNA Server/6000
commands between two systems and to analyze SNA protocol data.
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This trace will stop automatically when the link station is deactivated.
9.10.3.2 SNA Server/6000 Traces
SNA Server/6000 traces capture information pertaining to APIs and internal data.
API traces log entry and exit points for calls made to a programmable interface.
There are three API traces for SNA Server/6000:
•
•
•
SNA API
Generic SNA API
CPI Communications API
SNA Server/6000 internal traces capture information about important processing
events and low-level details of internal function flows.
If you wanted to mix SNA Server/6000 trace information with that of other
products in the same system trace file, you could do so by activating traces with
hook IDs. The hook IDs for SNA Server/6000 are:
271
SNA API trace
27A
Event and flow traces
27B
SNA failures
281
Generic SNA API trace
390
CPI Communications API trace
9.10.3.3 Starting and Stopping Traces
The traces can be controlled from SMIT, as follows:
Communications Applications and Services
→
SNA Server/6000
→
Problem Determination Aids
→
Control SNA Traces
→
Start and Stop Selected SNA Traces
Or use the fastpath: smit _snatrace.
This screen indicates which traces are currently enabled. These values can be
changed to turn on specific traces.
Chapter 9. X.25 Problem Determination
199
Start and Stop Selected SNA Traces
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
[]
off
off
off
[mbuftrc]
off
Link Station trace profile name(s)
API trace
Generic API trace
CPI-C trace
Event trace (list events)
Flow trace (select depth)
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
+
+
+
+
+
+
F4=List
F8=Image
9.10.3.4 Stopping All SNA Traces
You can turn off individual traces using the above method, but you can also turn
off all traces using the following SMIT path:
Communications Applications and Services
→
SNA Server/6000
→
Problem Determination Aids
→
Control SNA Traces
→
Stop All SNA Traces
Or use the fastpath: smit _snatraceoff.
This will stop all active SNA traces.
9.10.3.5 Formatting SNA traces
Having turned off your traces, they must be formatted before they can be viewed.
These formatted traces can be viewed from SMIT as follows:
Communications Applications and Services
→
SNA Server/6000
→
Problem Determination Aids
→
Show SNA Logs and Traces
Or use the fastpath: smit _snashow.
This will display the following screen.
200
RS/0000 X.25 Cookbook
Show SNA Logs and Traces
Move cursor to desired item and press Enter.
Show
Show
Show
Show
Show
API and Link Station Traces
Flow and Event Traces
SNA Failure Log
SNA Service Log
System Error Log
Switch SNA Log and Trace Files
F1=Help
F9=Shell
F2=Refresh
F10=Exit
F3=Cancel
Enter=Do
F8=Image
From here, you can select which trace you would like to see. Selecting Show
API and Link Station Traces provides a further two options:
•
•
Show API, Generic API or CPI-C Trace
Show Link Station Trace
Table 15 shows which hook IDs are used when creating the trace reports, using
the options mentioned above.
Table 15. Trace Reports and Associated Hook IDs
Report option
Hook IDs
Show API, Generic API or CPI-C
271, 281, 390
Flow and Event
27A
SNA Failure
27B
SNA Service
271, 27A, 27B, 281, 390.
9.10.4 LU 0 Information
LU 0 information can be obtained through traces.
9.10.4.1 LU 0 API Traces
LU 0 API traces can be controlled from the configuration profiles. When tracing
is enabled, SNA Server/6000 records trace information during each LU 0 API
subroutine call. The API trace is stopped when the application calls the lu0closes
or lu0closep subroutine.
Chapter 9. X.25 Problem Determination
201
9.10.4.2 LU 0 Server Traces
To start an LU 0 primary server trace, use the following command:
#lu0 -p PrimaryLineProfileName -t -b &
This command starts the LU 0 primary server as a background process and
starts the primary server trace.
.
To start an LU 0 secondary server trace, use the following command:
#lu0 -s LinkStationProfileName -t -b &
This command starts the LU 0 secondary server as a background process and
starts the secondary server trace.
The server traces stop automatically when the LU 0 server is stopped. These
traces do not need formatting to be viewed.
9.10.5 System Error Log
To ensure that all the data in the system error log is relevant, it is advisable to
first clear out the error log.
9.10.5.1 Clearing the System Error Log
Use the following SMIT path to clear the system error log:
Communications Applications and Services
→
SNA Server/6000
→
Problem Determination Aids
→
Control SNA Traces
→
Clear System Error Log
Or use the fastpath smit _snaerrclr.
Note: This will clear all errors from the system error log, not just the SNA
errors.
9.10.5.2 Showing the System Error Log
Use the following SMIT path to show the system error log:
Communications Applications and Services
→
SNA Server/6000
→
Problem Determination Aids
→
Show SNA Logs and Traces
→
Show System Error Log
Or use the fastpath smit _snasyserr.
9.10.6 HCON Trace
HCON has a trace capability built into the product. This can be used by:
# startsrc -s sna
/* Start sna
# e789 -D hcon.trace Sessionid
*************************
* Reproduce Problem *
/* Run Test Case
*************************
# stopsrc -s sna
/* Stop SNA services
# cp hcon.trace /tmp/pmr/hcon.trace
/* Save it
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RS/0000 X.25 Cookbook
9.10.7 SNA_ABEND
The SNA_ABEND file is created any time that SNA Server processes an exit
unexpectedly. Stopping SNA Services with the -c option will also create this file.
If the /var/sna/SNA_ABEND file is being created when the problem occurs, it will
need to be sent to the support organization.
9.10.8 Trace Hooks for X.25
If it is required to trace the internal workings of the X.25 stack, the following hook
IDs are available. These traces, along with a line trace from x25mon and a system
configuration table from lsx25, would help IBM diagnose the code′s behavior.
25C
Packet layer
329
X.25 TCP/IP interface
32A
NPI
32B
X.25 system utilities
32C
Triple-X PAD
33B
COMIO emulation
33C
Adapter driver
The traces produced from these hook IDs are not in a form that is directly useful
to a system user or system administrator. They are designed to allow defect
support to diagnose code flow.
9.11 System Errors
Severe X.25 failures may invoke system errors. Included here are some
indications of system errors and information to collect for problem determination.
9.11.1 Flashing 888
A flashing 888 in the three-digit display indicates that there is a message to be
displayed, encoded as a string of three-digit display values:
•
Turn the Key Mode Switch to the Normal position or the Service position.
•
Note: Every time you press the Reset button, hold it for about one second to
allow the program to sense the change.
Press the Reset button to display the first value in the string.
Record this value.
Repeat the above two steps until a flashing 888 is displayed again.
•
•
Up to 41 three-digit display values may be included in the string. If necessary,
you can display the entire string of values again by repeating the above
procedure.
The first value following the 888 indicates the type of information contained in the
remainder of the string. Find the first value in the following, and take the action
given:
Chapter 9. X.25 Problem Determination
203
9.11.1.1 Flashing 888-102
An initial value of 102 indicates an unexpected system halt during normal
operation. For unexpected system halts, the string of three-digit display values
has the following format:
888 102 mmm ddd
where mmm is a value indicating the cause of the halt and ddd is a value
indicating whether or not a system dump was obtained.
Refer to the Hardware Problem Determination Procedures in the IBM RISC
System/6000 Diagnostics Programs: Operator Guide . If these procedures return
an SRN, record that SRN in item four of the Problem Summary Form and report
the problem to your service organization. If Diagnostics does not detect a
problem, record SRN 101-mmm in item four of the Problem Summary Form and
report the problem to your service organization. If a system dump was obtained,
copy the dump to removable media and be prepared to make it available to your
service organization.
The following list gives the possible values of mmm, the second value following
the 888, and the cause of the system halt invoking that value:
•
•
200
201
202
203
204
205
206
207
300
32x
•
38x
•
•
400
500
•
52x
•
The number represented by “x” is the IOCC number
700 Program interrupt
800 Floating point unavailable
•
•
•
•
•
•
•
•
•
Machine check due to memory bus error (RAS/CAS Parity)
Machine check due to memory timeout
Machine check due to memory card failure
Machine check due to address exception: address out of range
Machine check due to attempted store into ROS
Machine check due to uncorrectable ECC due to address parity
Machine check due to uncorrectable ECC
Machine check due to undefined error
Data storage interrupt - processor type
Data storage interrupt - input/out exception - IOCC. The number
represented by x is the BUID
Data storage interrupt - input/output exception - SLA. The
number represented by x is the BUID
Instruction storage interrupt
External interrupt - Scrub - memory bus error (RAS/CAS Parity)
External interrupt - DMA - memory bus error (RAS/CAS Parity)
External interrupt - undefined error
External interrupt - IOCC type - channel check
External interrupt - IOCC type - bus timeout
External interrupt - IOCC type - keyboard external
The value of ddd, the third value following the 888, indicates the current dump
status. The possible values and meanings of ddd are:
•
•
•
•
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RS/0000 X.25 Cookbook
0c0 Dump completed successfully.
0c4 Partial dump completed.
0c5 Dump failed to start. An unexpected error occurred while the
system was attempting to write to the dump device.
0c8 Dump failed. No primary dump device is configured.
9.11.1.2 Flashing 888-103
An initial value of 103 indicates a diagnostic message. Diagnostic messages
appear in the three-digit display when the console display is not present, when
the the console display is unvailable because of a display or adapter failure or
when a failure is detected that prevents the completion of IPL.
The string of three-digit display values identifies the SRN and up to four Field
Replacement Units (FRUs). The string of three-digit display values has the
following format:
•
•
•
•
888
c02
c03
c04
103
1ee
1ee
1ee
nnn
2ee
2ee
2ee
nnn
3dd
3dd
3dd
c01
4dd
4dd
4dd
1ee
5ss
5ss
5ss
2ee
6ss
6ss
6ss
3dd 4dd 5 ss 6ss 7ff 8ff
7ff 8ff
7ff 8ff
7ff 8ff
The two values nnn nnn represent the SRN. The values c01, c02, c03 and c04
indicate the first, second, third and fourth FRUs, respectively. For each FRU, the
value sequence 1ee 2ee 3dd 4dd 5ss 6ss 7ff 8ff is the location code. Refer to the
IBM RISC System/6000 Diagnostics Programs: Operator Guide for information on
interpreting these location codes.
Record the SRN in item 4 of the Problem Summary Form and the location codes
in item 6 of the Problem Summary Form. Then, report the problem to your
service organization.
9.11.2 System Dump
The AIX dump facility records the state of the system at the time of the failure by
automatically copying selected operating system data areas to the dump device
when an unexpected system halt occurs.
If the system crashes or if you have invoked a dump, you need both the system
dump file and the /unix file to debug the problem. The system dump file is
usually put on the primary dump device, which in AIX Version 4 is now /dev/hd6.
Note: Invoking a system dump overwrites a previous dump or other data stored
on the dump device.
9.11.2.1 Starting a System Dump
A system dump can be invoked in a number of ways:
•
Turn the key lock switch to the Service position and press the Reset button.
This will create a dump on the primary dump device.
•
Turn the key lock switch to the Service position, hold down the Ctrl and Alt
keys and at the same time press the 1 key on the number pad. This will
create a dump on the primary dump device.
•
Turn the key lock switch to the Service position, hold down the Ctrl and Alt
keys and at the same time press the 2 key on the number pad. This will
create a dump on the secondary dump device.
•
Use the sysdumpstart command to invoke a dump on either the primary or
the secondary dump device.
Note: If the system has already halted and performed a dump, the Reset button
will scroll through the LEDs rather than trigger another dump.
Chapter 9. X.25 Problem Determination
205
9.12 Collecting Information for Resolution of X.25 Problems
Previous experience has shown us that specific information is needed for
technical support personnel to address defects correctly. This information will
help clarify customer scenarios, so all members of the defect support team
involved in a specific problem will know all the related data for a given X.25
environment.
9.12.1 List of Elements to Gather
1. Provide a copy of the network subscription (usually sent by fax).
Note: This is a document (usually 1 or 2 pages in length) that describes
exactly what the customer has purchased from the network provider.
2. Provide a copy of the x25mon output for each port by entering:
•
To start x25mon:
# x25mon -f -p -n sx25a? > x25mon.out &
•
To stop xmonitor:
# kill `ps -e | grep x25mon | cut -c0-6`
Note: Be sure to have the problem occur between the time x25mon started
and the time x25mon is stopped.
Warning: Do not use kill -9 to kill the x25mon command.
3. Provide a copy of the X.25 traces by entering:
•
To start tracing:
# trace -a -j 225,227,25c,329,32a,32b,32c,33b,33c,41f
•
To stop tracing:
# trcstop
•
To format the trace:
# trcrpt /usr/adm/ras/trcfile > trace.out
Note: Be sure to have the problem occur between the time tracing is started
and the time tracing is stopped.
4. Provide a file called “README” and put the following information in it:
•
•
•
•
•
•
•
•
•
•
A very detailed problem description
A description of what the trace data should be showing, that is, what type
of failure
A description of the hardware configuration
A detailed description of the network configuration
A picture of the network topology, all machines, routers, switches, etc.
A copy of any error messages sent to the screen
A description of all applications and/or software running on the system
A description of what events lead up to the failure
Time between failures, how often failures occur, etc.
What X.25 applications are running, SNA, SSI, TCP/IP, API, NPI, DLPI,
other....
5. Provide a copy of the device information output by entering:
# lsdev -C > devices.out
6. Provide a copy of the AIX software levels by entering:
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RS/0000 X.25 Cookbook
# lslpp -ha > levels.out
7. Provide a copy of the X.25 attributes by entering the following:
# lsattr -E -l sx25a? > lsattr1.out
Where ? is the number of the port
# lsx25 > lsx25.out and if running TCP/IP:
# lsattr -E -l xs? > lsattr2.out
Where ? is the number of the device
8. Provide a copy of the system error log report by entering:
# errpt -a > errpt.out
Note: Be sure to clear the error log before the problem occurs. To clear the
error log:
# errclear 0
9.13 How to Resolve an X.25 ′Device Busy′ Condition
While trying to change the configuration of the X25 device, you receive the error
″device not in correct state″. If you follow the steps below, you should be able to
change the configuration.
9.13.1 Problem Identification
When trying to update the X25 configuration via SMIT, the following message is
issued:
method error (/etc/methods/chgx25)
0514-029 Cannot perform the requested function because a child
device of the specified device is not in a correct state.
9.13.2 Problem Solution
To fix this problem, the user must stop all processes using the X.25 LPP. The
user cannot change attachment characteristics while a process is using X.25
because, technically, this process is holding the device open.
Some things to check:
•
Kill any x25mon or xtalk processes in the process table.
Use kill -15 on the process ID. Kill levels 2 and 3 are okay too. NEVER use
kill -9 to stop x25mon.
•
•
Stop any device driver tracing.
Bring the TCP/IP xsn interface to a defined state using the command rmdev -l
xsn.
•
Stop SNA (via SMIT or with the sna -stop sna -t normal command).
•
Stop the IBM Triple-X PAD daemon (x29d).
•
Stop the SNMP daemon (x25smuxd).
•
Stop anything running on COMIO, and then remove COMIO emulation from
the port to free it. Do this via SMIT and make sure you remove the definitions
Chapter 9. X.25 Problem Determination
207
from the database. Otherwise, when you re-create them, they use the next
available port name.
COMIO emulates the AIX V3 BOS X.25 device driver (/dev/x25s0) and allows
pre-LPP applications to run unchanged. Thus, check for all applications.
•
Stop any user-written NPI or DLPI applications.
The user should now be able to change the definitions of the X.25 device.
9.13.3 If All Else Fails
If all else fails and you cannot identify the culprit, the following workaround can
be used. Although this is a way around the situation, it is not an ideal solution to
the problem, as the system has to be rebooted.
1. Rename the adapter microcode found in directory /usr/lib/asw. The
Portmaster/A adapters use the sx25pma.cod file, and the X.25 Co-Processor
adapters use sx25cyc.cod.
2. Shut down and reboot the system.
3. When the system comes back up, make the desired changes via SMIT.
At this point, the adapter (apm0 or ampx0) should be available, but port
(xs25a#) should be defined. A user can modify a port′s characteristics as
long as that port is in a defined state. It is not necessary to disable all of the
ports on a single adapter or in a system. When using this workaround,
however, all ports of this type will become defined.
4. Change the microcode back to the correct name.
5. Either reboot or use SMIT ″Configure a Defined Port″ in the ″Manage X.25
Ports″ menu.
6. Restart any applications that were stopped in the previous steps.
9.14 Improving FTP Performance over X.25
If you experience problems when ftp′ing files over X.25 networks, here are a few
things to check that are most likely causing the problems.
•
Packet size - (1024 is a better size)
•
X25 Window Size - (this should be at least 7)
•
X25 packet size = MTU size
9.15 ARTIC960 Software Problems
ARTIC960 users must install the IBM ARTIC960 AIX Support Program for RS/6000
software shipped on a diskette packaged with the adapter. This software must
be at V1.1.3 or later.
Please make sure that this diskette is kept safe.
If in doubt as to the level of the software, you can check using the following
command:
•
lslpp -l devices.artic960.rte
The output should look something like this:
208
RS/0000 X.25 Cookbook
•
devices.artic960.rte
1.1.3.0
If the software is installed in the wrong order, then follow the recovery
procedures as documented in the Hardware Installation section of the
AIXLink/X25 1.1 for AIX: Guide and Reference manual.
If you install the ARTIC960 AIX Support Program for RS/6000 V1.1.3 after
installing AIXLink/X25, the following error may occur when you atempt to add a
″twd″ AIXLink/X25 device driver to the ARTIC960 adapter:
Method error (/usr/lib/methods/define):
0514-022 The specified connection is not valid.
If you encounter this error, then run the following script which should solve the
problem.
/usr/lpp/sx25/inst_root/sx25.rte.config
9.16 Examples of X.25 PAD Problem Determination
This section provides some further examples of X.25 problem determination
performed in real situations.
This may be of benefit to those who are unsure at what position in the
communication stack the problem lies.
Initial diagnosis of an X.25 problem should follow a methodical path that will lead
to a corrective action. There are many variables that constitute the X.25
network. Any incorrect value may result in an inoperative network. Often, a
large multiuser site communicating with users and printers via X.25 will not
tolerate downtime of the network. A few minutes spent isolating the source of
the problem at the time of failure can reduce subsequent downtime as the
correct party to resolve the problem can be called in. For example, your
network provider may not have facilities to modify the AIX X.25 configuration,
and similarly, your local AIX support organization may not have facilities to
modify the X.25 network settings. Transient problems can be resolved by
judicious tracing selection prior to the event occurring again.
9.16.1 Providing Initial Statement of Fault
The statement ′X.25 Network Inoperative′ does not reveal much to either your
X.25 network provider or to IBM specialists who are resolving the problems.
Work through the following table until you have found a problem. Skipping
applicable steps is not recommended, as they will only be repeated by your
support organization. Even when a problem would appear to be at a higher level
(that is, cannot print via X.25, cannot ping etc.), a lower-level problem often is
the cause. If a problem is reported to IBM, ensure the contact details of the X.25
network provider are available, as often the two parties will work together to
resolve a problem.
Chapter 9. X.25 Problem Determination
209
X.25 Network Provider
Do you have the contact details of your X.25 network provider?
You will often need the network provider on call to verify X.25 network
configuration and provide additional traces.
Table 16. X.25 Problem Checklist
Symptom
Layer
Refer
Physical
Hardware
9.16.2, “X.25 Hardware
Connection”
Devices
AIX Device Driver
9.16.3, “Device Driver” on
page 211
Connection State
Physical Frame or Packet
9.16.4, “Connection State” on
page 211
Total Line Termination
Physical Frame or Packet
9.16.5, “Total Line Termination or
Failure to Start” on page 212
No Traffic Flow
Physical Frame or Packet
9.16.6, “Connected to X.25
Network No Traffic Flow” on
page 214
Transient Dropouts
Packet
9.16.7, “Transient Dropouts” on
page 214
Hangs or Crashes
System
9.16.8.2, “System Hangs/Crashes
Caused by X.25 Software” on
page 216
Processes using X.25
System
9.16.8.1, “System Problems
Introduced by Disassociated X.25
Processes” on page 216
Printing
Application
9.16.9, “Printing” on page 216
9.16.2 X.25 Hardware Connection
Ensure physical integrity of X.25 cables connecting your network to your RS/6000
communication adapters.
Often, the cables connected to the RS/6000 communication adapter are large
with many pins. Ensure the cable head is screwed into the adapter and all pins
are intact.
If you have multiple ports, are you connected to the correct port?
Does your X.25 communications adapter support your X.25 network connection
speed?
210
RS/0000 X.25 Cookbook
9.16.3 Device Driver
The lscfg, lsx25 and lsdev commands should be used to ensure your X.25
communications adapter is known to the system and in the available state. For
example, following is a fragment of output from the lscfg command on a system
with one 6-port artic adapter with four X.25 ports configured:
+
*
*
*
*
*
*
*
*
*
apm0
twd0
sx25a0
x25s0
sx25a1
x25s1
sx25a2
x25s2
sx25a3
sx25a4
00-02
00-02-00
00-02-00-00
00-02-00-00-00
00-02-00-01
00-02-00-01-00
00-02-00-02
00-02-00-02-00
00-02-00-03
00-02-00-04
6-Port Portmaster Adapter/A X.21
The following output shows a fragment from the lsx25 command:
****************************************************************
* Report by X.25 port′ s logical location
*
****************************************************************
X.25
Logical Logical
Port
Driver NUA
COMIO TCP/IP board port
sx25a0 twd0
1200621 x25s0 n/a
0
0
sx25a1 twd0
1200621 x25s1 n/a
0
1
sx25a2 twd0
1200621 x25s2 n/a
0
2
sx25a3 twd0
1200621 n/a
n/a
0
3
sx25a4 twd0
1200621 n/a
n/a
0
4
****************************************************************
* Report by X.25 port′ s physical location
*
****************************************************************
X.25
Phys.
Port
Driver Adapter Slot
Port
Interface
sx25a0 twd0
apm0
2
0
X.21
sx25a1 twd0
apm0
2
1
X.21
sx25a2 twd0
apm0
2
2
X.21
sx25a3 twd0
apm0
2
3
X.21
sx25a4 twd0
apm0
2
4
X.21
Examine each port and driver via the lsdev -C -l <driver> command to ensure it
is in the available state.
9.16.4 Connection State
Prior to establishment of any communication, the physical, frame and packet
layers of the X.25 network connection must be up.
Use the x25status command to view the port state:
x25status
Link status for bfpvill01
Port
Packet State
sx25a0
PACKET LAYER CONNECTED
Active Active
SVCs
PVCs
23
0
Chapter 9. X.25 Problem Determination
211
sx25a1
sx25a2
PACKET LAYER CONNECTED
DISCONNECTED
2
0
0
0
In the example, the port sx25a2 is in a disconnected state. No communication
will be possible via that port. Examine the link parameters and/or trace the line
to find the cause of the problem.
9.16.5 Total Line Termination or Failure to Start
If you have a symptom involving all X.25 traffic being simultaneously terminated,
then suspect a network DISC is being sent from the X.25 network.
Following is sample output from the x25mon command:
x25mon -fpn sx25a0
14:59:33
14:59:33
14:59:39
14:59:39
14:59:39
14:59:39
14:59:39
14:59:39
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
FR
FS
FS
PS
FR
PR
FR
PR
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0001
DISC
UA
SABM
RESTART
UA
RESTART
INFO
CALL dN
a:3
a:3
a:1
c:0
a:1
c:7
a:3
p:1
p:1
p:1
d:161
p:1
d:0
p:0 ns:0 nr:0 1000FB0700
The trace shows the X.25 network has sent us a disconnect request. This would
disrupt all channels using the X.25 network.
Why is the network sending a DISC?
An x25mon trace of the few seconds leading up to the disconnect reveal the
answer:
14:59:25
14:59:25
14:59:25
14:59:25
14:59:25
14:59:25
14:59:25
14:59:25
14:59:25
14:59:26
14:59:26
14:59:27
14:59:27
14:59:28
14:59:29
14:59:30
14:59:31
14:59:32
14:59:33
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
sx25a0
FS
FS
FS
FR
FR
FS
FR
FR
FS
FS
PS
PS
FS
FS
PS
PS
FS
PS
FR
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x002b
0x0031
0x0000
0x0000
0x000f
0x002e
0x0000
0x0021
0x0000
INFO
INFO
INFO
INFO
INFO
INFO
INFO
RR
INFO
INFO
RR
RR
INFO
RR
RR
RR
RR
RR
DISC
a:1 p:0
a:1 p:0
a:1 p:0
a:3 p:0
a:3 p:0
a:1 p:0
a:3 p:0
a:1 p:0
a:1 p:0
a:1 p:0
pr:2
pr:2
a:1 p:0
a:1 p:1
pr:4
pr:4
a:1 p:1
pr:3
a:3 p:1
ns:1
ns:2
ns:3
ns:6
ns:7
ns:4
ns:0
nr:2
ns:5
ns:6
nr:6
nr:6
nr:6
nr:0
nr:0
nr:0
nr:1
100C7A1B3D2122DA
101B61
101B6236
101C01
101C21
101B641B3D2E24
100C85
nr:1 1022E1
nr:1 102B41
ns:7 nr:1 103141
nr:1
nr:1
As you can see, the first thing shown is us sending ns = 1 with a bunch of data.
Then, after the ns = 1 is sent by us, we send frames with ns = 2 and ns = 3.
These will be listed as outstanding frames. We receive ns = 6 and ns = 7 from
the network, and we ack them when we send a frame of ns = 4, via the nr = 0
(this acks 6 and 7 sent from the network). The network sends us a frame with ns
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RS/0000 X.25 Cookbook
= 0 and acks a previous frame via the nr = 1 (which will ack our frame 0 sent).
Then, the network acks the first thing listed above via the nr = 2 (our frame sent
with ns = 1). Then, we send frames of ns = 5 and ns = 6. The packet layer
sends two RRs. Then, we send a frame of ns = 7. At this point, our window
becomes full , and we have frames 2-7 that have yet to be acked by the network.
So, because the last acknowledgement we received was at 14:59:25, 3 seconds
after that, the T1 timer (which can be seen inthe Change/Show Frame
Parameters for the port and should match that of the network provider′s T1
timer) pops (14:59:28) − and thus, the poll that is sent by us showing correctly
that we have responded up to nr = 1 (packet sent to us with ns = 0). I am
reiterating this because this shows that we have NO outstanding packets to ack
that were sent by the network. Three seconds after that, at 14:59:31, we again
send a poll. (We will do this 10 times, as specified by the N2 timer again in the
Change/Show Frame Parms, before we will send a DISC ourselves). Then, as
shown at the very end of the trace, (14:59:33) a DISC is received.
The network provider increased the physical level idle timer to resolve the
problem.
Note: If we had forced the connection down ourselves, ( rmdev -l sx25a0) we
would have seen a DISC being sent by us, not received, from x25mon:
13:49:29
sx25a1 FS 0x0001 DISC
a:1 p:1
The following command sequence can be used to trace the establishment of
connection to the X.25 network.
1. rmdev -l sx25a0
2. x25mon -fpn sx25a0 > /tmp/x25mon.out &
3. mkdev -l sx25a0
Does the trace show incoming or outgoing calls after establishment of the
connection?
A successful network connection should show a set asynchronous balanced
mode frame (SABM) followed by an unnumbered acknowledgement (UA). You
should then see polls ′RR′ and, hopefuly, incoming call data (in the case of PAD
traffic).
23:32:00 sx25a0 FS 0x0000 SABM
23:32:00 sx25a0 FR 0x0000 SABM
23:32:00 sx25a0 PS 0x0000 RESTART
23:32:00 sx25a0 FS 0x0000 UA
23:32:00 sx25a0 FR 0x0000 UA
23:32:00 sx25a0 FS 0x0000 INFO
23:32:00 sx25a0 FR 0x0000 INFO
23:32:00 sx25a0 PR 0x0000 RESTART
23:32:00 sx25a0 FR 0x0000 RR
23:32:01 sx25a0 FS 0x0000 RR
23:32:02 sx25a0 FR 0x0000 INFO
10010BC7120062114170000000200001000000
23:32:02 sx25a0 PR 0x0001 CALL
a:1
a:3
c:0
a:3
a:1
a:1
a:3
c:7
a:1
a:3
a:3
p:1
p:1
d:161
p:1
p:1
p:0 ns:0 nr:0 1000FB00A1
p:0 ns:0 nr:0 1000FB0700
d:0
p:0 nr:1
p:0 nr:1
p:0 ns:1 nr:1
dN la:10 lf:0 ld:4
If you still cannot establish network connection, use a hardware line monitor to
watch the data flow.
Chapter 9. X.25 Problem Determination
213
------------------------|RS/6000 - X.25 Adapter |
|
|
------------------------on line monitor,
<------
---- Brick - Cable ---------- DCE
|
If two way traffic | If only SABMs from
but not on x25mon | adapter, upstream
downstream errors | errors ------>
9.16.6 Connected to X.25 Network No Traffic Flow
Examine an x25mon trace and look for a call confirm packet:
17:53:51 sx25a0 PR 0x0002 CALL
C7120062114170000000200001000000
17:53:51 sx25a0 PS 0x0002 CF CALL
dN la:10 lf:0 ld:4
dN la:10 lf:0 ld:0
Note that the call confirm corresponds to the call on the same logical channel
number (LCN). In this example, the LCN is 0x0002.
For PAD users, one reason for calls not being confirmed is the x29 daemon is
started in outbound mode only.
Locate the command used to start the x29 daemon in the file:
/etc/rc.x25
The x29 daemon should not be started with -n flag:
x29d -n
This will prevent incoming calls from being confirmed. Remove the -n flag if
incoming calls are desired.
Check the cause and diagnostic values for calls that are prematurely cleared.
9.16.7 Transient Dropouts
If your symptom involves an individual user or application terminating
unexpectedly while others continue to talk across the network, then suspect a
CLEAR packet is being sent or other application problem. You might see this
entry in the x25mon trace:
CLEAR c:0 d:241
With a site with many users and large amounts of X.25 traffic, you will need to
judiciously perform a trace to capture the problem event. It becomes overly
difficult trying to correlate problem events with trace files of the entire day′ s
traffic.
For example, the following shell script can be used to start a trace then have it
stop automatically once a problem event is detected. The script will restart
every 30 minutes using new trace files − so, when a problem is found, the
resultant trace files will be at most only 30 minutes′ worth of trace data.
#!/bin/ksh
# Detect a problem
cd /trace # some large File system
while :
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do
D=`date +%H%M%S%d%m` # timestamp each file
T=./trace.out.$D
X0=./x25mon.0.out.$D
U=./x25status.out.$D
# this traces X.25 hooks in a large trace buffer
trace -a -j 14e,255,277,25c,32c -l -T 2000000 -L 500000000 -o $T
x25mon -fpn sx25a0 > $X0 &
XPID0=$!
x25status > $U
m=0
while [ $m -lt 30 ] # 30 minutes
do
if grep CLEAR $X0 # Change the expression to whatever you need
then
trcstop
kill $XPID0
echo ″Caught″
exit 1
fi
sleep 5
let m=$m+1
done
trcstop
kill $XPID0
date
echo ″stop″
done
This can be used to trap disconnects (DISC), clears (CLEAR) or other problem
events you may be interested in.
9.16.7.1 User-Originated Clear Packets
The detection of a CLEAR packet in a x25mon trace may not necessarily indicate a
network error. Here are two examples of situations where a CLEAR packet
received with a diagnostic code of 241 related to user activity.
TERM: In the $HOME/.profile file, the $TERM environment variable was not set
correctly for particular PAD users. When the user was using a full screen ASCII
application, sometimes incorrect ASCII escape sequences were being generated
that simulated a break character, forcing the user off the network. Correct the
value of the $TERM environment variable to match the terminal type in use.
User-Generated CLEAR: In a large multiuser site, a number of frequent CLEARs
in the x25mon trace were noted. These were traced to users who were typing in
incorrect passwords once too many times, and the application was logging the
user out; this had the effect of clearing the logical channel associated with that
user.
Chapter 9. X.25 Problem Determination
215
For other diagnostics codes received with a CLEAR packet examine the
appropriate diagnostic value.
Another common reason for a CLEAR is that the number of LCN (logical channel
numbers) is exceeded and the X.25 connection cannot support additional users.
9.16.8 Application
X.25 applications may disrupt system operation in several ways.
9.16.8.1 System Problems Introduced by Disassociated X.25
Processes
If a network problem disrupts the X.25 network connection for a PAD user, the
user application will receive a SIGHUP signal. If the user application ignores or
catches this signal, then the application may continue to run in the background,
disassociated from its controlling terminal. In this case, the TTY column from
the output of the ps -ef command will show a ′ -′ field instead of the usual X.25
PAD pseudo terminal. This is not an X.25 problem as such, as the application
will need to clean itself up. Otherwise, the system administrator will need to
detect these rogue processes and take the appropriate action. Usually, this
would involve killing the process.
9.16.8.2 System Hangs/Crashes Caused by X.25 Software
A severe system problem induced by X.25 will not be trivial to detect, as a kernel
dump will need to be examined together with auxiliary traces. Typically, the
stack trace of running processes is examined to see if any X.25 kernel
extensions are present. In any case, we suggest you make the kernel dump
available to your support organization as per procedure in GG24-2513 AIX V4
Software Problem Debugging and Reporting
Look for these X25 kernel extensions in the kernel stack trace:
•
twd
•
x25pkt
If the event is readily repeatable, then it is suggested you run a kernel trace
using a pinned memory buffer. If a kernel dump is gathered after this event,
then valuable information regarding system activity leading up to the crash/hang
are stored in the kernel dump.
To start this trace at system boot time, place the following command near the
end of the /etc/rc system startup file:
trace -a -j 25C -L 1000000000 -o /trace/trace.out
Indicate this fact to your support organization so employees there can extract
the trace data from the kernel dump. You may be asked to add other kernel
trace hooks depending on the suspected region of code.
9.16.9 Printing
Problem
Cannot cancel remote job to X.25 network attached printer. The
remote printer did not appear to be printing.
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RS/0000 X.25 Cookbook
Suggestions
Restart qdaemon:
stopsrc -s qdaemon
lssrc -s qdaemon # ensure it is stopped
startsrc -s qdaemon
Ensure /var and / filesystems are not at 100% usage via the df
command.
Problem
During high volumes of print traffic, the printer appears to hang or
one working printer fails to print.
Suggestion
Perform an x25mon trace on the line to examine traffic flow.
The direction of traffic will depend on the configuration of the X.25
printer − that is, locally or remotely initiated.
Chapter 9. X.25 Problem Determination
217
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RS/0000 X.25 Cookbook
Chapter 10. Performance and Tuning
This chapter will explain performance considerations relevant when using X.25
networks with AIX in real situations.
The RISC System/6000 supports communications on an X.25 PSDN via V.24, V.35,
V.36 and X.21 interfaces. Overall performance depends upon a number of
factors, the major ones being network speed, network configuration parameters
and the application.
10.1 Line Speed
The speed within the network is under the control of the network provider. The
CCITT standards define network access up to 64 Kbps. So the maximum
obtainable line speed depends upon the type of connection. V.24, V.35 and X.21
line connections support speeds up to 19.2 Kbps, 56 Kbps and 64 Kbps,
respectively.
The following table gives a summary of the performance of the different line
speeds. Of course, this is the ideal and does not take into account such factors
as overhead for packetizing.
┌───────────────────────┬─────────────────────────────────────┐
│ Interface
│
V.24 | V.35 | X.21
│
├───────────────────────┼────────┬─────────┬─────────┬────────┤
│ Kbps
│ 9600 │ 19200 │ 64000 │ 64000 │
├───────────────────────┼────────┼─────────┼─────────┼────────┤
│ Bytes p/s
│ 1200 │ 2400 │ 7000 │ 8000 │
├───────────────────────┼────────┼─────────┼─────────┼────────┤
│ Packets p/s
│
9 │
18 │
54 │
62 │
│ (Packet size = 128) │
│
│
│
│
└───────────────────────┴────────┴─────────┴─────────┴────────┘
The V.36 and X.21 interfaces on the ARTIC960 adapter support speeds up to 2
Mbps.
10.2 Transit Delay Versus Data Throughput
A common error when calculating the throughput of a network between two
points is to first determine the time taken by a block of data to be transmitted
and acknowledged by a remote system, then to divide the transmitted block size
by the transmission time to obtain a throughput in bytes per second.
This method of calculation, which assumes that only one block of data is
traveling at a time on the network, is correct for protocols like BSC on a leased
line. It is not correct with an X.25 network, where the sender can send several
packets before the receiver has received the first one.
For an X.25 network, the transmission time is the sum of the following:
 Copyright IBM Corp. 1996
•
Sending application processing time
•
Packet assembly processing time by the X.25 adapter
•
Transmission time to the DCE
219
•
Transit time in the network
•
Transmission time from the sending DCE to the receiving DTE
•
Packet disassembly processing time by the X.25 adapter
•
Receiving application processing time
If the data transfer application is properly designed, the sender will not need any
acknowledgment of the previous packet from the receiver to send the next
packet. In this case, all these elementary delays are overlapped. When the
application prepares the data to be transmitted:
•
The X.25 adapter processes packet number n and transmits packet n-1 to the
DCE
•
A few packets may be travelling in the network
•
One packet is being sent from the remote DCE to the remote DTE
•
One packet is being processed by the adapter
•
Received data is processed by the application
In this case, the throughput of the data transfer will be limited by the slowest
part of the network.
10.3 Factors That May Limit Throughput
As explained in the previous section, the end-to-end maximum throughput is
limited by the throughput of the slowest part of the network. This is analogous to
a highway that has a throughput of 24000 cars per hour but may be limited to
2400 cars per hour if there is a section with road repairs in progress.
In the following section, we will describe the various factors that may influence
the X.25 performance:
•
X.25 adapter performance
•
DTE-to-DCE line speed and throughput class
•
Application design
10.3.1 X.25 Adapter
In some circumstances, the X.25 adapter attachment may limit the throughput.
The time taken by the attachment to process a packet is almost constant and
independent of the size of the packet. So if the packets are small and both the
DTE-to-DCE line speed and throughput class are high, the X.25 adapter may
spend more time assembling or disassembling packets than in sending them.
10.3.2 DTE-to-DCE Line Speed and Throughput Class
If we consider only the speed of the lines between the DCEs and DTEs and the
throughput class measuring the maximum throughput of the network itself, the
end-to-end throughput will be limited by the smallest of these two values. For
example:
•
220
RS/0000 X.25 Cookbook
If we have DTE-to-DCE lines at 19200 bps and the throughput class
subscribed to is 2400 bps, the theoretical throughput of the network will be
2400 bps.
•
If we have DTE-to-DCE lines at 2400 bps and a throughput class of 9600 bps,
the theoretical throughput of the network will also be 2400 bps.
The throughput class, which is the class of service you are paying for, and the
DTE-to-DCE clocking speed of the modems are apparently unrelated. However,
the previous example shows that the best price/performance ratio is achieved
when they both have the same value. Also, some networks do not implement
throughput class.
10.3.3 Influence of the Application Design
The way you write the data transfer application is also very important. Two
factors may limit the performance: the processing speed of the application that
cannot keep up with the transmission speed of the network, or a trade-of-design
like requesting an end-to-end acknowledgment of each packet before sending
the next. Let us consider, for example, a network with access lines at 19200 bps
and the same value for the throughput class. Suppose that the transit time in
the network is 200 ms (typical value) and you are sending 100-byte packets. If
you are waiting for acknowledgment from the other end before sending the next
packet, this will take 400 ms. In this case, the throughput will be only 100/.4 =
250 bytes per second.
10.4 Network Configuration Parameters
When you customize your network parameters, you must consider the following
points:
•
Since there is overhead with every packet, maximize the packet size and
send full packets whenever possible. Also, try to eliminate unnecessary
protocol-only packets for the higher level protocols like TCP/IP and SNA.
•
Do not use D-bit acknowledgement because it generates an
acknowledgement for each packet sent.
•
Maximize frame window size. Keep in mind that when a packet is lost, all the
packets of the window where the loss has occurred will be sent again. So,
when your network is reliable, you can set a big window size.
10.5 Applications
Performance considerations are mainly related to the applications. As a result,
some of the most commonly used applications are terminal emulators. We
should be aware of how terminal emulators behave in an X.25 network.
10.5.1 X.25 LPP PAD Versus TCP/IP
X.25 LPP PAD will always perform better than TCP/IP. The reason is that TCP/IP,
in general, and telnet, in particular, do not utilize the network very efficiently.
TCP/IP does the same thing on a PSDN that it does on a LAN, but because the
PSDN offers less bandwidth and the PSDN suppliers typically charge on a
per-packet basis, efficient network utilization can become very important to X.25
users.
Because PADs typically service dumb ASCII terminals (for example 3101, 3151,
PCs running asynchronous terminal emulation programs), they must provide
intelligence on behalf of the terminal. As the user types, the data is buffered by
the PAD (or RISC System/6000) until the data forwarding signal is received. This
Chapter 10. Performance and Tuning
221
signal is configurable (please refer to 5.1, “Using a PAD” on page 91) and
typically, it might just be a carriage return. When this signal is received, the
packet is made with the buffered data addressed to the target host and sent
across the network. Notice that you may not send a full packet, but you are
certainly sending more than one character here, so that is better than telnet. In
addition, you can set the PAD to provide the echo to the terminal so there is no
echo back from the remote host. There is no acknowledgement (X.25 provides
error detection/correction so TCP/IP′s is redundant) saving even more packets
than when using telnet.
Note: When a virtual circuit is established for an application such as X.25 LPP
PAD or TCP/IP between two sites, all traffic for that application flows over
that single virtual circuit. It allows you to minimize the number of SVCs.
10.5.2 TCP/IP
The telnet application tends to cause the transmission of many small packets.
This is not good utilization of X.25. The ftp application tends to send larger
packets and better utilizes X.25.
Telnet is an interactive application which generally sends a single character per
packet. To make matters worse, each character must also be echoed from the
remote system back to the user′s screen, then acknowledged. This means each
user keystroke typically generates three packets with telnet.
Choosing a batch-mode application like ftp means that the user will send full
packets for the most part. For maximum efficiency, users should consider the
relationship between the TCP/IP datagram size (the Maximum Transmission Unit
or MTU) and the X.25 packet size.
By definition, the maximum size of an IP datagram is 65536 bytes. Assuming a
20-byte IP header, this leaves up to 65516 bytes for the data in the datagram. If
the IP datagram exceeds the size of the underlying MTU, fragmentation occurs.
Every TCP/IP implementation must support a minimum IP datagram size of 576
bytes. A network can have an MTU smaller than 576 bytes, but any host must be
able to reassemble the fragmented IP packets into at least a 576-byte IP
datagram.
Since UDP packets are transmitted using IP, it is especially important to note
that if the sum of the UDP header and the IP header causes the datagram to
exceed the network′s MTU size, fragmentation will occur.
It is not the same for TCP. TCP breaks the data up into segments. The size of
the segment is negotiated between the two processes when the connection is
established.
To determine the MTU size, issue the following command:
# netstat -i
Here is an example of output:
Name
lo0
lo0
xt0
xt0
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RS/0000 X.25 Cookbook
Mtu
1536
1536
576
576
Network
<Link>
127
<Link>
9.3.5
Address
loopback
killix
Ipkts
20
20
67
67
Ierrs Opkts
Oerrs Coll
0
20
0
0
0
20
0
0
0
60
0
0
0
60
0
0
To modify the MTU size, you can use the ifconfig command or go through SMIT:
smit articmpx or smit portmaster
→
User Applications
→
TCP/IP
→
Network Interfaces
→
X25 LPP Network Interface Drivers
Or use the fastpath: smit chifsx25
X.25 LPP Network Interface Drivers
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
xs0
Network Interface
[1500]
Maximum IP PACKET SIZE for THIS DEVICE
F1=Help
F5=Undo
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
#
F4=List
F8=Image
If two machines on the same network have different MTU sizes set and they start
communicating across the network, problems can occur. This would happen
when a machine with a large MTU size has a packet to send which fits within its
MTU size but is larger than the MTU size of the receiving system. It is best to set
all machines on the network to the same MTU size.
The iptrace command is helpful in understanding how TCP/IP is utilizing the
network. The utilization characteristics are the same whether you are on token
ring, Ethernet or X.25. However, do not leave it running for longer than a couple
of commands because the trace information grows quickly. The procedure is:
1. To start iptrace:
# iptrace -d <server_name> -b /tmp/iptrace.out
2. Execute a couple of commands.
3. To stop the trace:
# kill `ps -e | grep iptrace | cut -c0-6`
4. To obtain a readable report of the trace:
# ipreport /tmp/iptrace.out > /tmp/ipreport
5. Then you can edit the resulting file: /tmp/ipreport.
You can also look at x25mon to see network utilization. Use the procedure:
Chapter 10. Performance and Tuning
223
1. To start xmonitor:
# x25mon -f -n -n sx25a0 > /tmp/x25mon_trace &
2. Run a couple of commands.
3. To stop xmonitor:
# kill `ps -e | grep x25mon | cut -c0-6`
4. Then you can edit the resulting file: /tmp/xmon_trace.
When reading the trace, a full packet with M-bit (also called the “MORE bit”) set,
followed immediately by a small packet, should signal users to review the
balance between packet and MTU sizes. The M-bit indicates that X.25 has to
fragment the data into more than one packet. It sets the M-bit to say that more
data follows. When very small packets always seem to follow a full packet, the
user must either decrease the application′s MTU size, or ask the network
provider for a larger X.25 packet size. The goal is to fill most of the packets,
either in a single packet or in successive packets using the M-bits. Note that you
can subscribe to up to 1KB packets in CCITT 1980 and 4KB packets in CCITT
1984 networks, but your per-packet charge is higher.
10.5.3 SNA
The options that we discussed earlier for TCP/IP also apply for SNA. Users must
balance the SNA Request/Response Unit (RU) size with the X.25 packet size. You
can use SNA and x25mon traces to visualize the traffic and customize the RU size
in case of problems.
10.6 Memory Buffers
The X.25 device driver (and all communications drivers) use mbufs for storing
data between the actual communications link and the application requesting the
data. Usually, there are not many mbufs available, as they are defined for
temporary storage. If a customer′s application is trying to send large data
sequences, it is very likely that the system will run out of mbufs in which to store
the incoming data. This will not kill the system, but it will probably disrupt all
communication facilities until you reboot the machine.
You can show the memory buffers using the command:
# netstat -m
Here is an example of the output of the netstat command:
224
369
mbufs in use:
262 mbufs allocated to data
1 mbufs allocated to packet headers
36 mbufs allocated to socket structures
52 mbufs allocated to protocol control blocks
8 mbufs allocated to routing table entries
7 mbufs allocated to socket names and addresses
3 mbufs allocated to interface addresses
0/18 mapped pages in use
164 KBytes allocated to network (56% in use)
0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines
RS/0000 X.25 Cookbook
If you have a value other than 0 in the two highlighted lines (request for memory
denied/delayed) then you will probably have to increase the number of mbufs:
•
With the no command
The no -a command will give you a list of all network options. The parameter
which deals with the mbufs is thewall. To change it, issue:
# no -o thewall=<new_value>
•
With the chdev command
Use first the lsattr command to show the value of the mbufs parameter:
# lsattr -E -l sys0
Here is an example of what we have on our system:
..
.
maxmbuf
..
.
2048
Maximum KBytes of real memory allowed for MBUFS True
To change the value, issue:
chdev -l sys0 -a maxmbuf=<new_value>
To simulate the overrunning of the mbufs, you can do a spray across the xs0
interface. This command uses TCP/IP, and it floods the adapter with datagrams
of the size and number you specify. This test, however, will not hang the system.
Rather, it will time out when TCP/IP decides that the network (the link) is no
longer responding.
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225
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RS/0000 X.25 Cookbook
Appendix A. Summary of the SMIT Main Menus Used for
Configuration
This appendix contains the SMIT configuration screens for the X.25 LPP base,
PAD, TCP/IP and SNA Server/6000 support. The screens shown are those for AIX
V4. For AIX V3.2.5, the screens may vary slightly.
A.1 X.25 Adapter Configuration
The following table contains all the SMIT screens that are used to configure an
X.25 adapter.
Table 17 (Page 1 of 4). SMIT Menus for the Base X.25 Configuration
F a s t p a t h = smit cx25str_dd
After having installed the X.25 LPP, if you are using the
X.25 CoProcessor/2, you need to install the device
driver.
Manage X.25 LPP Device Driver
Move cursor to desired item and press Enter.
List All Configured Device Drivers to a CoProcessor/2 Adapter
Add a Device Driver
Remove a Device Driver
Configure a Defined Device Driver
Manage X.25 Ports
- A Manage the X.25 Triple-X PAD
- B -
Devices
→Communications
→X.25 CoProcessor/2 or Multiport/2 Adapter
→Adapter
→Manage Device Drivers for X.25 ...
→Manage X.25 LPP Device Driver
→Add a Device Driver
-------------------------------------------------------------------------|
Parent Adapter
|
|
|
| Move cursor to desired item and press Enter.
|
|
|
|
ampx0 Available 00-04 X.25 CoProcessor/2 Adapter
|
|
|
| F1=Help
F2=Refresh
F3=Cancel
|
| F8=Image
F10=Exit
Enter=Do
|
F1| /=Find
n=Find Next
|
F9 --------------------------------------------------------------------------
F a s t p a t h = smit cx25str_mp
Manage X.25 Ports
A - Manage X.25 Ports
Move cursor to desired item and press Enter.
List All Defined Ports
Add Port
Move Port Definition
Change / Show Characteristics of Port
Remove Port
Configure a Defined Port
Add Comio Interface to Port
Remove Comio Interface from Port
Add TCP/IP Interface to Port
Remove TCP/IP Interface from Port
 Copyright IBM Corp. 1996
F1=Help
F9=Shell
F2=Refresh
F10=Exit
- 1 - 2 -
F3=Cancel
Enter=Do
F8=Image
227
Table 17 (Page 2 of 4). SMIT Menus for the Base X.25 Configuration
F a s t p a t h = smit mksx25c
Add an X.25 Port
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
twd0
[0]
[3106010760]
[other private]
[]
Parent adapter driver
* PORT number
* Local network user address (NUA)
* Network identifier
Country prefix
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
+
#
+
#
F4=List
F8=Image
F a s t p a t h = smit x25str_mp_csp
Change / Show Characteristics of Port
This screen allows access to the detailed parameters
of the X.25 Configuration.
Move cursor to desired item and press Enter.
Change
Change
Change
Change
Manage
228
RS/0000 X.25 Cookbook
F1=Help
F9=Shell
/ Show General Parameters
/ Show Packet Parameters
/ Show Frame Parameters
/ Show Default for Permanent Virtual Circuits
Non-Default Permanent Virtual Circuit
F2=Refresh
F10=Exit
F3=Cancel
Enter=Do
F8=Image
Table 17 (Page 3 of 4). SMIT Menus for the Base X.25 Configuration
F a s t p a t h = smit x25str_mp_csp_g_sel
Fastpath = smit x25str_mp_csp_p_sel
Change / Show X.25 General Parameters
Change / Show X.25 Packet Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
Port name
Local network user address (NUA)
Calling address in call request/accept packet
Enable DLPI interface ONLY
PVC - lowest logical channel number
PVC - Number of logical channels
Incoming SVC - lowest logical channel number
Incoming SVC - number of logical channels
Two-way SVC - lowest logical channel number
Two-way SVC - number of logical channels
Outgoing SVC - lowest logical channel number
Outgoing SVC - number of logical channels
X.32 Configuration
******************
Use X.32 XID Exchange
X.32 XID Identity
X.32 XID signature
Dial-Up Configuration
********************
Connection Type
V25bis Call Establishment Method
Phone Number or Address to Call
Maximum Connection Delay
Enable/Disable DSR Polling
DSR polling timeout
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
sx25a0
[3106010760]
[allow]
[no]
[0]
[0]
[0]
[0]
[1]
[64]
[0]
[0]
#
+
+
+#
+#
+#
+#
+#
+#
+#
+#
[no]
[]
[]
+
[Direct/Leased]
[Addressed]
[]
[10]
[disable]
[30]
+
+
F3=Cancel
F7=Edit
Enter=Do
[TOP]
Port name
CCITT support
Packet modulo
Type of line
Packet layer DTE/DCE line alteration policy
Disconnect on inactivity
Registration
A-bit
Network intermediate data unit (nidu) size
#
#
F4=List
F8=Image
Change / Show X.25 Frame Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
sx25a0
[3]
[1]
[15]
[0]
[10]
[8]
[7]
[yes-automatic]
[active-sendSABM]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
Default Attributes for SVCs
**********
Default receive packet size
Default transmit packet size
Default receive packet window
Default transmit packet window
Default receive throughput class
Default transmit throughput class
[128]
[128]
[3]
[3]
[64000]
[64000]
+#
+#
+#
+#
+#
+#
Maximum Negotiable Attributes for SVCs
**********
Maximum receive packet size
Maximum transmit packet size
Maximum receive packet window
Maximum transmit packet window
[1024]
[1024]
[5]
[5]
+#
+#
+#
+#
ISO8208-Defined Timers
**********
T20 restart timer
T21 call timer
T22 reset timer
T23 clear timer
T24 window status transmission timer
T25 window rotation timer
T26 interrupt timer
T27 reject response timer
T28 registration timer
R20 retransmission count restart timer
R22 retransmission count reset timer
R23 retransmission count clear timer
R25 retransmission count window rotation timer
R27 retransmission count reject timer
R28 retransmission count registration timer
[180]
[200]
[180]
[180]
[60]
[200]
[180]
[60]
[300]
[3]
[3]
[3]
[0]
[0]
[1]
+#
+#
+#
+#
+#
+#
+#
+#
+#
+#
+#
+#
+#
+#
+#
[allow]
[allow]
[allow]
[109]
[32]
+
+
+
+#
+#
Packet-Level Features
**********
Fast select mode
D-bit
Reverse charging
Maximum facility field length
Interrupt data size
[BOTTOM]
+#
+#
+#
+#
+#
+#
+#
+
+
F1=Help
F5=Reset
F9=Shell
+#
+#
+
+
+
+
+
+#
+
F a s t p a t h = smit x25str_mp_csp_f_sel
Port name
T1 retransmission timer
T2 acknowledgement timer
T3 idle timer
T4 activity timer
N2 retransmission count
Frame modulo
Frame window size
Allow automatic DTE/DCE detection
Connection mode
[Entry Fields]
sx25a0
[1988]
[8]
[DTE]
[per OSI 8208 procedure]
[no]
[no]
[off]
[200]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
F4=List
F8=Image
Appendix A. Summary of the SMIT Main Menus Used for Configuration
229
Table 17 (Page 4 of 4). SMIT Menus for the Base X.25 Configuration
F a s t p a t h = smit x25str_mp_csp_d_sel
Change / Show X.25 Default PVC Parameters
These screens are used for PVC configuration only.
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Port name
PVC receive
PVC maximum
PVC maximum
PVC maximum
PVC D-bit
F1=Help
F5=Reset
F9=Shell
[Entry Fields]
sx25a0
[128]
[128]
[3]
[3]
[allow]
packet size
transmit packet size
receive packet window
transmit packet window
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
+#
+#
+#
+#
+
F4=List
F8=Image
F a s t p a t h = smit x25str_mp_mnd_a_sel
Add X.25 Non-Default PVC Parameters
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Port name
* PVC number
PVC receive
PVC maximum
PVC maximum
PVC maximum
PVC D-bit
F1=Help
F5=Reset
F9=Shell
[Entry Fields]
sx25a0
[]
[128]
[128]
[3]
[3]
[allow]
packet size
transmit packet size
receive packet window
transmit packet window
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
#
+#
+#
+#
+#
+
F4=List
F8=Image
F a s t p a t h = smit x25str_pad
Manage the X.25 Triple-X PAD
B - Manage the X.25 Triple-X PAD
Move cursor to desired item and press Enter.
This screen is used for the PAD function only.
Start the Triple-X PAD X.29 Daemon
Stop the Triple-X PAD X.29 Daemon
230
RS/0000 X.25 Cookbook
F1=Help
F9=Shell
F2=Refresh
F10=Exit
F3=Cancel
Enter=Do
F8=Image
A.2 TCP/IP Configuration
The following is a quick way to customize TCP/IP over the X.25 link. Table 18
only shows the main SMIT screens used for this configuration.
Note: Of course, only the screens for one RISC System/6000 are described.
Table 18 (Page 1 of 3). SMIT Menus for the TCP/IP Configuration
F a s t p a t h = smit mktcpip
Minimum Configuration & Startup
To Delete existing configuration data, please use Further Configuration menus
Communications
→TCP/IP
→Minimum Configuration & Startup
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
[kili]
[9.3.5.205]
[255.255.255.0]
xt0
* HOSTNAME
* Internet ADDRESS (dotted decimal)
Network MASK (dotted decimal)
* Network INTERFACE
NAMESERVER
Internet ADDRESS (dotted decimal)
DOMAIN Name
Default GATEWAY Address
(dotted decimal or symbolic name)
START TCP/IP daemons Now
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
[9.3.1.74]
[itsc.austin.ibm.com]
[9.3.1.74]
no
F3=Cancel
F7=Edit
Enter=Do
+
F4=List
F8=Image
F a s t p a t h = smit configtcp
Further Configuration
Communications
→TCP/IP
→Further Configuration
Move cursor to desired item and press Enter.
Hostname
Static Routes
Network Interfaces
Name Resolution
Client Network Services
Server Network Services
Manage Print Server
Select BSD style rc Configuration
F1=Help
F9=Shell
F2=Refresh
F10=Exit
- 3 - 1 -
F3=Cancel
Enter=Do
F8=Image
Appendix A. Summary of the SMIT Main Menus Used for Configuration
231
Table 18 (Page 2 of 3). SMIT Menus for the TCP/IP Configuration
F a s t p a t h = smit mkhostent
Add a Host Name
1 - Create an entry in /etc/hosts for the local and
remote hosts.
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
* INTERNET ADDRESS (dotted decimal)
* HOST NAME
ALIAS(ES) (if any - separated by blank space)
COMMENT (if any - for the host entry)
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
[Entry Fields]
[9.3.5.205]
[kili]
[]
[]
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
F a s t p a t h = smit inet
Communications
→TCP/IP
→Further Configuration
→Network Interfaces
Network Interface Selection
Move cursor to desired item and press Enter.
List All Network Interfaces
Add a Network Interface
Change / Show Characteristics of a Network Interface
Remove a Network Interface
X.25 LPP IP Host Configuration
F1=Help
F9=Shell
F2=Refresh
F10=Exit
F3=Cancel
Enter=Do
- 2 - 4 -
F8=Image
F a s t p a t h = smit chinet or smit mkinetxt
Change / Show an X.25 LPP Network Interface
2 - Initialize and start IP/X.25 interface.
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Network Interface Name
INTERNET ADDRESS (dotted decimal)
Network MASK (hexadecimal or dotted decimal)
Current STATE
232
RS/0000 X.25 Cookbook
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
[Entry Fields]
xt0
[9.3.5.205]
[255.255.255.0]
up
+
F4=List
F8=Image
Table 18 (Page 3 of 3). SMIT Menus for the TCP/IP Configuration
F a s t p a t h = smit mkroute
Add a Static Route
3 - Add a static route for each remote host if you use
two different IP network addresses.
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Destination TYPE
* DESTINATION Address
(dotted decimal or symbolic name)
* GATEWAY Address
(dotted decimal or symbolic name)
* METRIC (number of hops to destination gateway)
Network MASK (hexadecimal or dotted decimal)
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
[Entry Fields]
host
[129.35.1.93]
+
[9.3.1.74]
[1]
[255.255.255.0]
F3=Cancel
F7=Edit
Enter=Do
#
F4=List
F8=Image
F a s t p a t h = smit mksx25s
Add X.25 LPP IP SVC Host Entry
4 - For each remote host, create an entry in the IP
hostname to NUA translation table.
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[TOP]
[Entry
* Remote HOSTNAME
* Remote DTE Address
---------- Optional X.25 Facilities ---------RECEIVED data PACKET size
TRANSMITTED data PACKET size
RECEIVED data WINDOW size
TRANSMITTED data WINDOW size
CLOSED USER GROUP selection
CLOSED USER GROUP WITH OUTGOING ACCESS selection
Recognized Private Operating Agency (RPOA)
User-Defined Facilities
---------- CALL USER Data -------------------Note: RFC-1356 (supersedes RFC-877) mandates
the first byte of call user data is 0xcc. If you
do not put ′ cc′ as the first byte, SMIT
will put it there for you.
Call User Data
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
Fields]
[fili]
[3106010761]
#
+
+
[]
[]
[]
[]
[]
[]
#
#
#
#
[]
F4=List
F8=Image
Appendix A. Summary of the SMIT Main Menus Used for Configuration
233
A.3 SNA Configuration
First, you must add the X.25 QLLC Data Link Control for the X.25 Co-Processor.
From the first menu of the SMIT interface, select:
Devices
→
Communication
→
X.25 Coprocessor/2 or Multiport/2 Adapter
→
Services
→
X.25 QLLC Data Link Controls
→
Add a QLLC Data Link Control
Or use the fastpath: smit cmddlc_qllc_mk.
If using the Portmaster Adapter:
Devices
→
Communication Devices
→
Portmaster Adapter/A
→
Services
→
Data Link Controls
→
Add an SDLC Data Link Control
Or use the fastpath: smit cmddlc_sdlc_mk.
The system gives you a dlcqllc as available.
Then you can go on with the SNA configuration profiles that are required to use
SNA over X.25. (See Table 19 on page 235.)
Figure 56. AIX SNA Services/6000 Main Profiles
234
RS/0000 X.25 Cookbook
Table 19 (Page 1 of 4). SMIT Menus for the SNA Configuration
F a s t p a t h = smit _snainit
To perform the Inital Node Setup, from the SMIT main
menu select:
Initial Node Setup
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Initial Node Setup
[Entry Fields]
[AUSCP]
appn_end_node
[USIBMRA]
[*]
Control Point name
Control Point type
Local network name
XID node ID
+
Optional link station information:
Link station type
Link station name
* Calling link station?
Remote X.25 station address
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
x.25_svc
[]
yes
[3106001984]
F3=Cancel
F7=Edit
Enter=Do
+
X
F4=List
F8=Image
F a s t p a t h = smit _snacpch
To change the Control Point Profile from the SMIT main
menu select:
Change/Show Control Point Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Advanced Configuration
→Control Point
→Change/Show a Profile
* Profile name
XID node ID
Network name
Control Point (CP) name
Control Point alias
Control Point type
Maximum number of cached routing trees
Maximum number of nodes in the TRS database
Route addition resistance
Comments
F1=Help
F5=Reset
F9=Shell
[Entry Fields]
node_cp
[*]
[USIBMRA]
[AUSCP]
[AUSCP]
appn_end_node
[500]
[500]
[128]
+
#
#
#
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Appendix A. Summary of the SMIT Main Menus Used for Configuration
235
Table 19 (Page 2 of 4). SMIT Menus for the SNA Configuration
F a s t p a t h = smit _snaX25linkmk
To create the SNA DLC Profile from the SMIT main
menu, select:
Add X.25 SNA DLC Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Advanced Configuration
→Links
→X.25
→X.25 SNA DLC
→Add a Profile
[TOP]
* Profile name
Data link device name
Force disconnect time-out (1-600 seconds)
User-defined maximum I-Field size?
If yes, Max. I-Field size (265-30729)
Max. num of active link stations (1-255)
Number reserved for inbound activation
Number reserved for outbound activation
Local X.25 network address
Receive window count (1-127)
Transmit window count (1-127)
236
RS/0000 X.25 Cookbook
+
#
+
#
#
#
#
#
#
#
Secondary and Negotiable Stations
Secondary inactivity time-out (1-255 sec)
[30]
#
Primary and Negotiable Stations
Primary repoll frequency (1-255 seconds)
Primary repoll count (1-255)
[30]
[10]
#
#
Link Recovery Parameters
Retry interval (1-10000 seconds)
Retry limit (0-500 attempts)
[60]
[20]
#
#
Comments
[BOTTOM]
[Entry Fields]
[xdlc]
[x25s0]
[120]
no
[1417]
[100]
[0]
[0]
[3106010760]
[7]
[7]
F1=Help
F5=Reset
F9=Shell
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Table 19 (Page 3 of 4). SMIT Menus for the SNA Configuration
F a s t p a t h = smit _snaX25attcmk
To create a link station profile from the SMIT main
menu, select:
Add X.25 Link Station Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Advanced Configuration
→Links
→X.25
→X.25 Link Station
→Add a Profile
[TOP]
* Profile name
Use APPN Control Point′ s XID node ID?
If no, XID node ID
* SNA DLC Profile name
Stop link station on inactivity?
If yes, Inactivity time-out (0-10 minutes)
LU address registration?
If yes, LU Address Registration Profile name
Trace link?
If yes, Trace size
X.25 level
Station type
Adjacent Node Identification Parameters
Verify adjacent node?
Network ID of adjacent node
CP name of adjacent node
XID node ID of adjacent node (LEN node only)
Node type of adjacent node
Link Activation Parameters
Solicit SSCP sessions?
Initiate call when link station is activated?
Virtual circuit type
If permanent,
Logical channel number of PVC (1-4095)
If switched,
Listen name
Remote station X.25 address
X.25 Optional Facilities Profile name
Activate link station at SNA start up?
Activate on demand?
CP-CP sessions supported?
If yes,
Adjacent network node preferred server?
Partner required to support CP-CP sessions?
Initial TG number (0-20)
Restart Parameters
Restart on activation?
Restart on normal deactivation?
Restart on abnormal deactivation?
Transmission Group COS Characteristics
Effective capacity
Cost per connect time
Cost per byte
Security
Propagation delay
User-defined 1
User-defined 2
User-defined 3
no
[]
[]
[*]
learn
+
+
+
#
+
+
+
+
+
+
+
+
yes
yes
switched
+
+
+
[1]
#
[IBMQLLC]
[3106001984]
[xfacs]
no
no
no
#
+
+
+
+
no
no
[0]
+
+
no
no
no
+
+
+
#
[9600]
#
[128]
#
[128]
#
public_switched_networ> +
packet_switched_networ> +
[128]
#
[128]
#
[128]
#
Comments
[BOTTOM]
F1=Help
F5=Reset
F9=Shell
[Entry Fields]
[xlink]
yes
[07100123]
[xdlc]
no
[0]
no
[]
no
long
1984
secondary
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Appendix A. Summary of the SMIT Main Menus Used for Configuration
237
Table 19 (Page 4 of 4). SMIT Menus for the SNA Configuration
F a s t p a t h = smit _snaX25optsmk
To create an X.25 optional facilities profile, from the
SMIT main menu, select:
Add X.25 Optional Facilities Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Advanced Configuration
→Links
→X.25
→X.25 Optional Facilities
→Add a Profile
[TOP]
* Profile name
Throughput class for received data
Throughput class for transmitted data
Closed user group?
If yes, Index to closed group
Closed user group outgoing access?
Network user identification?
If yes,
Network user ID name
Network user ID in hex?
Reverse charging?
RPOA?
If yes, Data network ID codes
Packet size for received data
Packet size for transmitted data
[Entry Fields]
[xfacs]
9600
9600
no
[0]
no
no
Comments
[BOTTOM]
[]
F1=Help
F5=Reset
F9=Shell
F2=Refresh
F6=Command
F10=Exit
[]
no
no
no
[]
128
128
F3=Cancel
F7=Edit
Enter=Do
+
+
+
#
+
+
+
+
+
+
+
F4=List
F8=Image
F a s t p a t h = smit _snasess2mk
To create an LU 2 session profile using the manual
method, from the SMIT main menu, select:
Add LU 2 Session Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Advanced Configuration
→Sessions
→LU 2
→Add a Profile
[Entry Fields]
[xsess02]
[S4080502]
[2]
* Profile name
Local LU name
* Local LU address (1-255)
System services control point
(SSCP) ID (*, 0-65535)
Link Station Profile name
Network name
Remote LU name
Maximum number of rows
Maximum number of columns
[*]
[xlink]
[]
[]
[24]
[80]
Comments
An LU 2 session profile will need to be created for
each display session required over X.25.
F1=Help
F5=Reset
F9=Shell
#
+
#
#
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
F a s t p a t h = smit _snasess3mk
To create an LU 3 session profile using the manual
method, from the SMIT main menu, select:
Add LU 3 Session Profile
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
Communications Applications and Services
→SNA Server/6000
→Configure SNA Profiles
→Advanced Configuration
→Sessions
→LU 3
→Add a Profile
An LU 3 session profile will need to be created for
each printer session required over X.25.
RS/0000 X.25 Cookbook
[*]
[xlink]
[]
[]
[24]
[80]
Comments
238
[Entry Fields]
[xsess09]
[S4080509]
[9]
* Profile name
Local LU name
* Local LU address (1-255)
System services control point
(SSCP) ID (*, 0-65535)
Link Station Profile name
Network name
Remote LU name
Maximum number of rows
Maximum number of columns
F1=Help
F5=Reset
F9=Shell
#
+
#
#
[]
F2=Refresh
F6=Command
F10=Exit
F3=Cancel
F7=Edit
Enter=Do
F4=List
F8=Image
Appendix B. Differences Between X.25 LPP and AIX V3 Base X.25
Support
If you are migrating from the AIX V3 base X.25 support to the X.25 LPP you will
likely want to know what are the main differences between them. In this chapter
we will explain what hardware, functionality, configuration and setup procedures
have been changed with the new X.25 LPP.
B.1 Hardware Differences
The X.25 LPP supports:
•
The X.25 Co-Processor/2 adapter (FC 2960)
•
The X.25 Co-Processor ISA-bus adapter (FC 6753), only on AIX Version 4.1
machine with an ISA-bus and AIXlink/X.25 LPP
•
The ARTIC Portmaster Adapter/A with 1MB (FC 7006)
•
The ARTIC Portmaster Adapter/A with 2MB (FC 7008)
•
The ARTIC960 Adapter with 8-port RS232 daughter card (FC 2929)
•
The ARTIC960 Adapter with 6-port V.36/V.35 daughter card (FC 2936)
•
The ARTIC960 Adapter with 8-port X.21 daughter card (FC 2938)
•
The ISA Portmaster Multiport/2 (PS/2 FC 6590 (USA), FC 5309 (EMEA))
The ARTIC Portmaster Adapters with 1MB and 2MB can now be used to connect
to an X.25 network. They are Portmaster adapters which support V.24, V.35 and
X.21 interfaces.
Table 20. X.25 Supported Adapters
Adapter
AIX V3 Base X.25
support
X.25 LPP
supported
supported
X.25 Co-Processor ISA-bus
not supported
AIXLink Only
ARTIC Portmaster Adapter/A 1MB
not supported
supported
ARTIC Portmaster Adapter/A 2MB
not supported
supported
ARTIC960 Adapter
not supported
AIXLink V1.1.3 or
later
ISA Multiport/2 Adapter
not supported
AIXLink V1.1.3 or
later
X.25 Co-Processor/2 Micro Channel
B.2 Functionality Differences
The X.25 LPP provides the following new features:
 Copyright IBM Corp. 1996
239
X.25 LPP New Features
•
Support of the International Telegraph and Telephone Consultative
Committee (CCITT) 1988 X.25
•
Packet Layer Programming Interface Network Provider Interface (NPI)
•
Frame Layer Programming Interface Data Link Provider Interface (DLPI)
•
Compatibility application program interface (API) for applications written
to the base Version 3 X.25 support
•
Triple-X (X.3, X.28, X.29) Packet Assembler/Disassembler (PAD)
•
PAD supported printing
•
Configurable PAD access controls
•
Dial up on demand facility
•
Simple Network Management Protocol (SNMP) support for data items
from the machine instruction buffers (MIBs) for the packet and frame
layers
•
V25bis support
•
Supports up to 512 logical channels per line
•
Automatic DTE configuration
•
Supports an aggregate sustained rate of 200 128-bytes packets per
second (measured at the packet layer API) for each adapter in the
system
Table 21. Functional Differences
Functionality
AIX V3 base X.25
support
X.25 LPP
1984
1988
NPI
NO
YES
DLPI
NO
YES
API Library
YES
YES•
PAD Support
NO•
YES
SNA Support
YES
YES
TCP/IP Support
YES
YES
SNMP Support
NO
YES
Automatic DTE configuration
NO
NO
Logical channels per line
64
512
Packets per second (128-byte packets)
35
200
CCITT Conformance
Note:
•Applications based on the API library are only supported when the COMIO emulator
is configured on the port.
•Only with third-party software.
240
RS/0000 X.25 Cookbook
B.2.1 Differences between (CCITT) 1988 and 1984 X.25
The 1988 recommendations further refine and expand the CCITT X.25.
B.2.1.1 Packet Layer
The main differences between CCITT 1994 and 1988 X.25 recommendations at the
packet level are:
Network User Identification (NUI): Facilities related to Network User
Identification (NUI) have been
into divided into three parts:
•
NUI_subscription
•
NUI_override
•
NUI_selection
DTE/DTE Operation: DTE-to-DTE operation without an intervening network has
been defined. In this situation, one DTE must act as DCE. The DTE acting as
DCE at packet layer may be acting as DTE at Data Link Layer and vice versa.
This is an optional facility.
Circuit-switched Connection without Prior Agreement: A circuit-switched
connection without prior agreement (such as electronic mail-order) has been
defined and default values specified for all applicable parameters. This is an
optional capability.
Throughput Class of 64000 bits/s: A new throughput class of 64000 bits per
second has been defined. This is an optional capability.
Address Block Definition: A new Address Block has been defined for call setup
and clearing packets which allows addresses of 12 or 15 digits. This is an
optional capability.
TOA/NPI Address Subscription: A new facility, TOA/NPI_Address_Subscription,
has been added to accommodate E.164 (ISDN) addresses of up to 17 digits in
length. This addition results in a redefinition of the address block and the
consequent definition of new formats for the CALL_REQUEST, CALL_ACCEPTED,
CALL_CONECTED, CLEAR_REQUEST, CLEAR_INDICATION and
CLEAR_CONFIRMATION packets. This is an optional capability.
Call Deflection: Call_Deflection_selection facilities whereby the DTE forwards
calls after receiving an INCOMING_CALL packet (unlike CALL_REDIRECTION,
which is handled in the network and the originally called DTE never receives an
INCOMING_CALL packet) has been added. There are three call deflection
facilities:
•
Call_Deflection_Subscription, which enables the DTE to request
Call_Deflection_Selection.
•
Call_Deflection_Selection, which may be used on a per-virtual-call basis only
if Call_Deflection_Subscription has been subscribed to.
•
Call_Deflection_Notification, which informs the alternate DTE that the call has
been forwarded.
These are optional user facilities.
Appendix B. Differences Between X.25 LPP and AIX V3 Base X.25 Support
241
Priority Facility: A Priority Facility has been added to specify the priority of data
on a connection and the priority to keep a connection. This is an optional
capability.
Protection Facility: A Protection Facility has been added to specify the
protection of data on a connection.
Maximum Size of Called and Calling Address Extension: The maximum size of
the called and calling address extension fields is extended from 32 to 40 digits,
and an OSI/non-OSI indicator has been added. Support of the larger address is
optional. However, a test of the OSI/non-OSI indicator is required to determine
the size of the called and calling address.
Recognized Private Operating Agency: RPOA-related facilities have been
subdivided into:
•
RPOA_Subscription, which applies to all virtual calls
•
RPOA_Selection, which applies to a given virtual call and does not require
RPOA_Subscription
These are optional capabilities.
Mandatory Address Length Fields in CALL_ACCEPTED Packets: The use of the
address-length fields in CALL_ACCEPTED packets is mandatory, even if they are
set to zero.
Mandatory Facility Length Fields in CALL_ACCEPTED packets: The use of the
Facility Length Fields in CALL_ACCEPTED packets is mandatory, even if they are
set to zero.
Virtual Circuit Clearing/Resetting Failure: When a CLEAR_REQUEST packet is
not confirmed within time-limit T23, the DTE will retry the call clearing procedure
up to R23 times, at T23 intervals, before notifying the higher layer (virtual circuit
user) of the failure; this leaves the logical channel in the DTE_CLEAR_REQUEST
state (p6) rather than placing the logical channel in an inoperative state, as
specified by early versions.
When a RESET_REQUEST packet is not confirmed within time-limit T22, the DTE
will retry the resetting procedure up to R22 times, at T22 intervals, before
notifying the higher layer (virtual circuit user) of the failure; this leaves the
logical channel in the DTE_RESET_REQUEST state (d2) rather than placing the
logical channel in an inoperative state, as specified by early versions.
B.2.1.2 Frame Layer
The main differences between CCITT 1994 and 1988 X.25 recommendations at the
frame level are:
DTE/DTE Operation: Although not specified in CCITT Recommendation X.25,
International Standard Organization ISO 7776 supports communication between
two DTEs without an intervening network. Since there is no intervening network,
link layer characteristics must be made by bilateral agreement rather than at at
subscription time. This is an optional capability but is required if communicating
using Open Systems-Interconnect (OSI).
242
RS/0000 X.25 Cookbook
Clearing a FRMR Condition at the DCE: After the DCE has transmitted an FRMR
response, the frame rejection condition is cleared when the DCE receives an
FRMR response (in addition to when a SABM/SABME, DISC or DM is sent or
received).
Maximum Number of Outstanding I-Frames: American National Standards ANS
X3.100 specifies that all networks must support k=7. K is the maximum number
of outstanding I-frames.
B.3 Configuration and Setup Differences
Installation and Setup Differences
•
You need to order and install the X.25 LPP.
•
You do not need to install the adapter microcode.
There is one exception to this, and that is the microcode for the ARTIC960
adapter, which is supplied on diskette with the adpater.
•
You do not need to use xmanage to connect to the network.
•
Several SMIT fastpaths have changed.
•
Several attribute names have changed.
Since the X.25 LPP is a Licensed Program Product, your first step in your
configuration and setup procedure is to install the X.25 code. You do not need to
install the microcode from diskette anymore, it is now installed with the LPP.
Your next step is to configure the device driver and the X.25 port. As soon as
your X.25 port is configured and available, the X.25 LPP software tries to bring
up the frame and packet layer, which means that you don′t have to use xmanage
to connect to the X.25 network. The command xmanage is not supported by the
X.25 LPP.
You′ll probably need to change some attributes such as number of virtual
circuits, throughput, etc. If you are going to use SMIT fastpaths, be aware that
many of them have changed.
Table 22. SMIT Fastpaths Differences
Parameter
Old SMIT Fast Path
New SMIT Fast Path
Change / Show X.25
General Parameters
x25csg
x25str_mp_csp_g_sel
Change / Show X.25
Frame Parameters
x25csf
x25str_mp_csp_f_sel
Change / Show X.25
Packet Parameters
x25csp
x25str_mp_csp_p_sel
The xroute command works only with X.25 ports that have COMIO emulation
configured and must be used only when you have applications which use this
emulation ( xtalk, SNA, ...). The new TCP/IP implementation does not use the
COMIO emulation, so you no longer need to add xroute entries when using more
than one X.25/IP interface.
The X.25 LPP allows you to enable/disable only these two facilities:
•
Fast Select
Appendix B. Differences Between X.25 LPP and AIX V3 Base X.25 Support
243
•
Reverse Charging
B.4 Command Differences
Many commands that were used for management and configuration purposes
have changed.
Command Differences Summary
•
The x25mon command is now used for tracing an X.25 port.
•
The x25ip command is now used for managing the NUA/IP table.
•
The lsx25 command has been added for listing the configuration of the
X.25 support on the system.
•
The x25status command has been added to display the status of the
connection between the DTE and the DCE.
•
The x25debug command has been added to enable more in-depth
diagnostics to be carried out on the device driver and microcode.
The xmonitor comand does not exist anymore. The x25mo n command is now
used to trace an X.25 port.
Table 23. Differences Between xmonitor and x25mon
xmonitor
x25mon
Frame
Layer
-frame
-f
Packet
Layer
-packet
-p
Port
x25s n
-n sx25a n
The x25ip command has the same syntax than the x25xlate command.
The lsx25 command uses information available from the system configuration
database to display the relationship between adapters, drivers, ports, etc. that
are configured to use X.25.
The x25status command is a partial replacement for the xmanage function in the
BOS X.25 facility. It enables the system administrator the ability to interigate the
status of the X.25 ports. However, it does NOT enable the ports to be
manipulated like the xmanage facility.
B.5 ODM/SMITAttributes Differences
Table 24 shows the differences in attribute names.
Table 24 (Page 1 of 2). SMIT Attribute Names
244
AIX V3 X.25 Support
AIX X.25 LPP
num_in_out_svc
bi_vc_num
in_out_svc
bi_vc_start
ccitt_support
ccitt
RS/0000 X.25 Cookbook
Table 24 (Page 2 of 2). SMIT Attribute Names
AIX V3 X.25 Support
AIX X.25 LPP
connection_mode
connect_seq
d_bit
d_bit_accept
pvc_d_bit
def_pvc_d_bit
def_rx_pkt_size
def_rx_size
def_rx_through
def_rx_th
def_rx_pkt_win
def_rx_win
def_tx_pkt_size
def_tx_size
def_tx_through
def_tx_th
def_tx_pkt_win
def_tx_win
frame_modulo
f_modulo
fast_select
fs_mode
num_in_svcs
in_vc_num
in_svc
in_vc_start
line_type
line_type
local_nua
local_nua
max_rx_pkt_size
max_rx_size
max_rx_pkt_win
max_rx_win
max_tx_pkt_size
max_tx_size
max_tx_pkt_win
max_tx_win
n2_counter
n2
network_id
network_id
num_out_svcs
out_vc_num
out_svc
out_vc_start
pkt_modulo
pkt_modulo
num_of_pvcs
pvc_num
pvc_channel
pvc_start
rev_charging
rev_charge
t1_timer
t1
t21_timer
t21
t22_timer
t22
t23_timer
t23
t24_timer
t24
t25_timer
t25
t26_timer
t26
t4_timer
t4
zero_address
zero_address
Appendix B. Differences Between X.25 LPP and AIX V3 Base X.25 Support
245
B.6 Default Values of Important Parameters
The default values of several important parameters have changed. Table 25
shows the differences between the AIX V3 base X.25 support and the X.25 LPP.
Table 25. Default Values of Important Parameters
246
Parameter
AIX V3 base
X.25 Defaults
X.25 LPP Defaults
Frame window size
7
7
Frame modulo
8
8
Packet modulo
8
8
CCITT support
1980
1984
Default receive packet size
128
128
Default transmit packet size
128
128
Default receive packet window
2
3
Default transmit packet window
2
3
Default receive throughput class
9600
64000
Default transmit throughput class
9600
64000
RS/0000 X.25 Cookbook
Appendix C. X.25 Cables and Connectors
This appendix will be divided into two sections. Section C.1, “IBM X.25
Co-Processor and IBM X.25 Co-Processor/2” describes the cables and
connectors used with the IBM X.25 Co-Processor and the IBM X.25
Co-Processor/2. These adapters use the same cables and connectors. Any
reference to the X.25 Co-Processor or Co-Processor applies to both adapters.
Section C.2, “IBM Portmaster Adapter/2 and Multiport Model 2” on page 257
describes the cables and connectors used with the IBM ARTIC Portmaster
Adapter/2, Multiport Model 2 and ARTIC960 adapters.
C.1 IBM X.25 Co-Processor and IBM X.25 Co-Processor/2
This section describes the cables and connectors used with the IBM X.25
Co-Processor and the IBM X.25 Co-Processor/2. These adapters use the same
cables and connectors. Any reference to the X.25 Co-Processor, X.25
Co-Processor/2 or Co-Processor applies to both adapters.
Figure 57. Co-Processor Adapters
 Copyright IBM Corp. 1996
247
C.1.1 X.25 Co-Processor 37-Pin Connector Pin Assignment
Table 26.
Pin
X.25 Co-Processor 37-Pin Connector Pin Assignment
Circuit Designation
Symbol
X.21bis /V24
X.21bis /V35
X.21
1
Reserved
2
Transmitted data
TXD
x
3
Received data
RXD
x
4
Request to send
RTS
x
x
5
Clear to send
CTS
x
x
6
Data set ready
DSR
x
x
7
Signal ground
GND
x
x
8
Carrier detect
CD
x
x
9
Cable ID 0
ID0
x
10
Transmitted data (A)
T (A)
x
11
Control (A)
C (A)
x
12
Received data (A)
R (A)
x
13
Indication (A)
I (A)
x
14
Transmit clock (A)
S (A)
x
15
Cable ID 1
ID1
16
Receive clock (B)
RX CLK (B)
x
17
Transmitted data (B)
TXD (B)
x
18
Transmit clock (B)
TX CLK (B)
x
19
Receive data (B)
RXD (B)
x
20
Data terminal ready
DTR
x
21
Remote loopback test
RLBT
x
22
Call indicate
CI
x
23
Reserved
24
Transmit clock
TX CLK
x
25
Test indicate
TI
x
26
Receive clock
RX CLK
x
27
Local loopback test
LLBT
x
x
x
x
x
x
28
Transmitted data (B)
T (B)
x
29
Control (B)
C (B)
x
30
Received data (B)
R (B)
x
31
Indication (B)
I (B)
x
32
Transmit clock (B)
S (B)
x
33
Reserved
34
Receive clock (A)
RX CLK (A)
x
35
Transmitted data (A)
TXD (A)
x
36
Transmit clock (A)
TX CLK (A)
x
37
Received data (A)
RXD (A)
x
248
RS/0000 X.25 Cookbook
C.1.2 X.25 Co-Processor Modem Attachment Pin Assignment
Supported modem types include the V.11, V.24/X.21bis and V.35/X.21bis
attachments.
C.1.2.1 X.21 Pin Assignment
Table 27. Pin Assignment of V.11 Type of Interface Circuits to 15-Pin Connectors
PIN
NUMBER
CIRCUIT
ASSIGNMENT
1•
2
3
4
5
6
7
8
9
10
11
12
13
14
15
T(a)•
C(a)
R(a)
I(a)
S(a)
B(a)/X(a)
G
T(b)•
C(b)
R(b)
I(b)
S(b)
B(b)/X(b)
Future use
Circuit Description
Transmit
Control
Receive
Indication
Signal element timing
Byte timing/Modem transmit signal (not used)
Signal ground or common return
Transmit
Control
Receive
Indication
Signal element timing
Byte timing/Modem transmit signal (not used)
Future use
Note:
•Assigned for connecting the shields between tandem sections of shielded interface cables.
•(a) and (b) indicate pins which are associated to form pairs.
G - Signal ground (or common return):
In the case of interchange circuits according to Recommendation
V.11, it interconnects the zero volt reference points of a generator and
a receiver to reduce environmental signal interference, if required.
T - Transmit:
The binary signals originated by the system to be transmitted during
the data transfer phase via the data circuit to one or more remote
systems are transferred on this circuit to the modem.
This circuit also transfers the call control signals originated by the
system to be transmitted to the modem in the call establishment and
other call control phases as specified by the relevant
recommendations for the procedural characteristics of the interface.
The modem monitors
conditions, according
characteristics of the
modem as defined in
characteristics of the
this circuit for detection of electrical circuit fault
to the specifications of the electrical
interface. A circuit fault is interpreted by the
the recommendation for the procedural
interface.
R - Receive:
The binary signals sent by the modem as received during the data
transfer phase from a remote system are transferred on this circuit to
the system.
This circuit also transfers the call control signals sent by the modem
as received during the call establishment and other call control
Appendix C. X.25 Cables and Connectors
249
phases as specified by the relevant recommendation for the
procedural characteristics of the interface.
The system monitors this circuit for detection of electrical circuit fault
conditions, according to the specifications of the electrical
characteristics of the interface. A circuit fault is to be interpreted by
the system as defined in the recommendations for the procedural
characteristics of the interface.
C - Control:
Signals on this circuit control the modem for a particular signalling
process.
Representation of a control signal requires additional coding of circuit
T-Transmit as specified in the relevant recommendation for the
procedural characteristics of the interface. During the data phase, this
circuit must remain ON. During the call control phases, the condition
of this circuit must be as specified in the relevant recommendation for
the procedural characteristics of the interface.
The modem monitors this circuit for detection of electrical circuit fault
conditions, according to the specifications of the electrical
characteristics of the interface. A circuit fault is to be interpreted by
the modem as defined in the recommendation for the procedural
characteristics of the interface.
I - Indication:
Signals on this circuit indicate to the system the state of the call
control process.
Representation of a control signal requires additional coding of circuit
R-Receive, as specified in the relevant recommendation for the
procedural characteristics of the interface. The ON condition of this
circuit signifies that signals on circuit R contain information from the
distant system. The OFF condition signifies a control signalling
condition which is defined by the bit sequence on circuit R as
specified by the procedural characteristics of the interface.
The system monitors this circuit for detection of electrical circuit fault
conditions, according to the specifications of the electrical
characteristics of the interface. A circuit fault is to be interpreted by
the system as defined in the recommendation for the procedural
characteristics of the interface.
S - Signal element timing:
Signals on this circuit provide the system with signal element timing
information from the modem. The condition of this circuit is ON and
OFF for nominally equal periods of time. However, for burst
asynchronous operations, longer periods of the OFF condition may be
permitted equal to an integer odd number of the nominal period of the
ON condition as specified by the relevant procedural characteristics
of the interface.
The system must present a binary signal on circuit T-Transmit and a
condition on circuit C-Control, in which the transitions nominally occur
at the time of the transitions from the OFF to ON condition of this
circuit.
250
RS/0000 X.25 Cookbook
The modem presents a binary signal on circuit R-Receive and a
condition on circuit I-Indication in which the transitions nominally
occur at the time of the transitions from the OFF to ON condition of
this circuit.
The modem transfers signal element timing information on this circuit
across the interface whenever the timing source is capable of
generating this information.
C.1.2.2 V.24/X.21bis Pin Assignment
Table 28. V.24/X.21bis Pin Assignment to 25-Pin Connector (Speeds up to 20 Kbps)
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
CCITT
Circuit
103
104
105
106
107
102
109
114
115
141
108
140
125
142
CCITT Circuit Designation
Transmitted data
Received data
Request to send
Ready for sending
Data set ready
Signal ground
Received line signal detector
N
N
N
N
F
F
Tx signal element timing from modem
F
Rx signal element timing from modem
Local loopback
F
Data terminal ready/ Connect data set to line
Local loopback
Calling indicator
N
F
Test indicator
Note:
N
Pin permanently reserved for national use.
F
Pin reserved for future international standard and should not be used for
national use.
Appendix C. X.25 Cables and Connectors
251
C.1.2.3 V.35/X.21bis Pin Assignment
Table 29. V.35/X.21bis Pin Assignment to 34-Pin Connector (Speeds above 20 kbps)
Pin
CCITT
Circuit
CCITT Circuit Designation
Direction
Common
A
B
102
Signal ground or common return
C
105
Request to send
D
106
Ready for sending
To system
E
107
Data set ready
To system
F
109
Data channel received line sig. detect.
To system
H
108.2
J
125
Calling indicator
To system
K
141
Local loopback
Not Used
L
-
F
-
M
-
F
-
N
140
Loopback/Maintenance test
P
103
Transmitted data
A-wire
From system
R
104
Received data
A-wire
To system
S
103
Transmitted data
B-wire
From system
T
104
Received data
B-wire
To system
U
113
Tx sig. elem. timing from system
A-wire
Not Used
V
115
Receiver signal element timing
A-wire
To system
W
113
Tx sig. elem. timing from system
B-wire
Not Used
X
115
Receiver signal element timing
B-wire
To system
Y
114
Tx sig. elem. timing from modem
A-wire
To system
Z
-
AA
114
BB
-
F
-
CC
-
F
-
DD
-
F
-
EE
-
F
-
FF
-
F
-
HH
-
N
-
JJ
-
N
-
KK
-
N
-
LL
-
N
-
MM
-
F
-
NN
142
From system
Data terminal ready
From system
Not Used
F
Tx sig. elem. timing from modem
Test indicator
B-wire
To system
Not Used
Note:
252
N
Pin permanently reserved for national use.
F
Pin reserved for future international standard and should not be used for national
use.
RS/0000 X.25 Cookbook
C.1.2.4 V.36 Pin Assignment
Table 30. V.36 Pin Assignment to 37-Pin Connector
Pin
CCITT
Circuit
Signal Name
Direction
04
103
TXDnA
From system
22
103
TXDnB
From system
06
104
RXDnA
To system
24
104
RXDnB
To system
05
114
TCLKInA
To system
23
114
TCLKInb
To system
08
115
TCLKInA
TO system
26
115
TCLKInB
To system
17
113
TCLKOnA
From system
35
113
TCLKOnB
From system
07
105
RTSn
From system
09
106
CTSn
To system
13
109
DCDn
To system
12
108.2
DTRn
From system
11
107
DSRn
To system
19
102
SigGnd(-)
01
-
-
-
C.1.3 X.25 Co-Processor Interconnection Cables
This section shows the pin assignments for the Co-Processor-to-modem
interconnection cables.
C.1.3.1 X.21 Interface Cable
D-37 Connector
D-15 Connector
┌─────────────┐
┌─────────────┐
│ T(A)
10├──────────┤2
T(A) │
│ C(A)
11├──────────┤3
C(A) │
│ R(A)
12├──────────┤4
R(A) │
│ I(A)
13├──────────┤5
I(A) │
│ S(A)
14├──────────┤6
S(A) │
│ GND
7 ├─────X────┤8
GND │
│ T(B)
28├─────┼────┤9
T(B) │
│ C(B)
29├─────┼────┤10
C(B) │
│ R(B)
30├─────┼────┤11
R(B) │
│ I(B)
31├─────┼────┤12
I(B) │
│ S(B)
32├─────┼────┤13
S(B) │
│ ID0
9 ├─────┘
│
ID0 │
└─────────────┘
└─────────────┘
Transmitted data (A)
Control (A)
Received data (A)
Indication (A)
Transmit clock (A)
Signal ground
Transmitted data (B)
Control (B)
Received data (B)
Indication (B)
Transmit clock (B)
Figure 58. X.21 Interface Cable
Appendix C. X.25 Cables and Connectors
253
C.1.3.2 X.21bis/V.24 Interface Cable
D-37 Connector
D-25 Connector
┌─────────────┐
┌─────────────┐
│ TXD
2├──────────┤2
TXD
│
│ RXD
3├──────────┤3
RXD
│
│ RTS
4├──────────┤4
RTS
│
│ CTS
5├──────────┤5
CTS
│
│ DSR
6├──────────┤6
DSR
│
│ GND
7├─────X────┤7
GND
│
│ CD
8├─────┼────┤8
CD
│
│ TX CLK
24├─────┼────┤15
TX CLK │
│ RX CLK
26├─────┼────┤17
RX CLK │
│ LLBT
27├─────┼────┤18
LLBT │
│ DTR
20├─────┼────┤20
DTR
│
│ RLBT
21├─────┼────┤21
RLBT │
│ CI
22├─────┼────┤22
CI
│
│ TI
25├─────┼────┤25
TI
│
│ ID0
9├─────┤
│
ID0
│
│ ID1
15├─────┘
│
ID1
│
└─────────────┘
└─────────────┘
Figure 59. X.21bis/V.24 Interface Cable
254
RS/0000 X.25 Cookbook
Transmitted Data
Received Data
Request to Send
Clear to Send
Data set ready
Signal ground
Carrier detect
Transmit clock
Receive clock
Local loopback test
Data terminal ready
Remote loopback test
Call indicate
Test indicate
C.1.3.3 X.21bis/V.35 Interface Cable
D-37 Connector
M/34 Connector
┌──────────────┐
┌────────────────┐
│ GND
7├─────X─────┤B
GND
│
│ RTS
4├─────┼─────┤C
RTS
│
│ CTS
5├─────┼─────┤D
CTS
│
│ DSR
6├─────┼─────┤E
DSR
│
│ CD
8├─────┼─────┤F
CD
│
│ DTR
20├─────┼─────┤H
DTR
│
│ CI
22├─────┼─────┤J
CI
│
│ TXD(A)
35├─────┼─────┤P
TXD(A)
│
│ RXD(A)
37├─────┼─────┤R
RXD(A)
│
│ TXD(B)
17├─────┼─────┤S
TXD(B)
│
│ RXD(B)
19├─────┼─────┤T
RXD(B)
│
│ RX CLK (A) 34├─────┼─────┤V
RX CLK (A)│
│ TX CLK (A) 36├─────┼─────┤Y
TX CLK (A)│
│ RX CLK (B) 16├─────┼─────┤X
RX CLK (B)│
│ TX CLK (B) 18├─────┼─────┤AA
TX CLK (B)│
│ ID1
15├─────┘
│
ID1
│
└──────────────┘
└────────────────┘
Signal ground
Request to Send
Clear to Send
Data set ready
Carrier detect
Data Terminal Ready
Call indicate
Transmitted data (A)
Receive data (A)
Transmitted data (B)
Receive data (B)
Receive clock (A)
Transmit clock (A)
Receive clock (B)
Transmit clock (B)
Figure 60. X.21bis/V.35 Interface Cable
C.1.4 X.25 Co-Processor Adapter and Cable Diagnostics
Adapter and cable wrap plugs, used for diagnostics, are automatically included
with cables and X.25 adapter orders specifying the RISC/6000 order numbers.
The following wrap plug pin assignments, taken from the X.25 Co-Processor/2
Hardware Technical Reference manual , are listed below.
They are supplied for local loopback tests in accordance with CCITT
Recommendation X.150:
•
D-37 wrap plug
•
D-15 wrap plug
•
D-25 wrap plug
•
M/34 wrap plug
C.1.4.1 D-37 Wrap Plug - Co-Processor
The D-37 wrap plug is used to test local loopback at the D-37 connector on the
adapter. It has a cable identifier of ID0=1, ID1=1.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal
Pin no.
Pin no. Signal │
│ T(B)
28
30
R(B) │
│ T(A)
10
12
R(A) │
│ C(B)
29
31
I(B) │
│ C(A)
11
13
I(A) │
│ TXD
2
3
RXD
│
│ RTS
4
5
CTS
│
│ DTR
20
6
DSR
│
│ LLBT
27
25
TI
│
│ RLBT
21
22
CI
│
│ TXD(A)
35
37
RXD(A) │
│ TXD(B)
17
19
RXD(B) │
│ ID0
9
15
ID1
│
└───────────────────────────────────────────────┘
Figure 61. D-37 Wrap Plug
Appendix C. X.25 Cables and Connectors
255
C.1.4.2 D-15 Wrap Plug - Co-Processor, X.21
The D-15 wrap plug is used to test loopback at the DCE end of the X.21 interface
cable.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal
Pin no.
Pin no. Signal │
│ T(B)
9
11
R(B) │
│ T(A)
2
4
R(A) │
│ C(B)
10
12
I(B) │
│ C(A)
3
5
I(A) │
└───────────────────────────────────────────────┘
Figure 62. D-15 Wrap Plug
C.1.4.3 D-25 Wrap - Plug Co-Processor, V.24
The D-25 wrap plug is used to test loopback at the DCE end of the X.21bis/V.24
interface cable.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal
Pin no.
Pin no. Signal │
│ TXD
2
3
RXD
│
│ RTS
4
5
CTS
│
│ DTR
20
6
DSR
│
│ LLBT
18
25
TI
│
│ RLBT
21
22
CI
│
└───────────────────────────────────────────────┘
Figure 63. D-25 Wrap Plug
C.1.4.4 M/34 Wrap Plug - Co-Processor, V.35
The M/34 wrap plug is used to test loopback at the DCE end of the X.21bis/V.35
interface cable.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal
Pin no.
Pin no. Signal │
│ TXD(A)
P
R
RXD(A) │
│ TXD(B)
S
T
RXD(B) │
│ RTS
C
D
CTS
│
│ DTR
H
E
DSR
│
└───────────────────────────────────────────────┘
Figure 64. M/34 Wrap Plug
256
RS/0000 X.25 Cookbook
C.2 IBM Portmaster Adapter/2 and Multiport Model 2
The cables and connectors described in this section are for use with the IBM
Portmaster Adapter/2 and Multiport Model 2. The cables and connectors are
interchangable between the adapters and have the same pin assignments.
Figure 65. Portmaster and Multiport
C.2.1 IBM ARTIC Portmaster Adapter/A Pin-Out Information
The following tables describe the pin assignments of the interface cables:
C.2.1.1 V.35 Pin Assignment
Table 31 (Page 1 of 2). Portmaster and Multiport: V.35
Mnemonic
I/O
Port
0
Port
1
Port
2
Port
3
Port
4
Port
5
25-Position Connector
TxDA
O
94
21
47
71
72
23
02
TxDB
O
70
46
22
95
96
48
14
RxDA
I
08
54
58
29
28
57
03
RxDB
I
33
78
82
04
03
81
16
TxCA IN
I
76
06
77
56
27
55
15
TxCB IN
I
52
31
53
80
02
79
12
Appendix C. X.25 Cables and Connectors
257
Table 31 (Page 2 of 2). Portmaster and Multiport: V.35
Mnemonic
I/O
Port
0
Port
1
Port
2
Port
3
Port
4
Port
5
25-Position Connector
RxCA
I
20
41
38
19
32
30
17
RxCB
I
45
16
13
44
07
05
09
TxCA OUT
O
24
73
98
25
99
26
24
TxCB OUT
O
49
97
74
50
75
51
11
RTS
O
42
43
92
93
37
39
04
CTS
I
15
65
86
87
59
09
05
DCD
I
89
40
62
61
35
84
08
DTR
O
18
91
69
68
14
12
20
DSR
I
66
90
88
64
60
85
06
SGND
-
34
17
63
67
01
83
07
FGND
-
100
shield
TxDA, TxDB Transmit Data
RxDA, RxDB Receive Data
TxCA IN, TxCB IN Transmit Clock (DCE clock)
RxCA, RxCB Receive Clock (DCE clock)
TxCA OUT, TxCB OUT Transmit Clock (DTE clock)
258
RS/0000 X.25 Cookbook
01
C.2.1.2 V.24 Pin Assignment
Table 32. Portmaster and Multiport: V.24
Mnemonic
I/O
Port
0
Port
1
Port
2
Port
3
Port
4
Port
5
Port
6
Port
7
25-Position Connector
TxD
O
51
54
07
10
13
16
94
48
02/BA
RxD
I
02
05
83
86
89
92
46
74
03/BB
RTS
O
01
04
82
85
88
91
45
73
04/CA
CTS
I
77
80
34
37
40
43
71
24
05/CB
DCD
I
28
31
59
62
65
68
21
99
08/CF
DTR
O
76
79
33
36
39
42
70
23
20/CD
DSR
I
53
56
09
12
15
18
96
50
06/CC
HRS
I
27
30
58
61
64
67
20
98
23/CI
RI
I
03
06
84
87
90
93
47
75
22/CE
TxCLKIN
I
29
32
60
63
66
69
22
100
15/DB
TxCLK
O
52
55
08
11
14
17
95
49
24/DA
RxCLK
I
78
81
35
38
41
44
72
25
17/DD
SGND
-
19
19
26
26
57
57
97
97
07/AB
FGND
Cable Shield
01/AA
Note: x stands for port number
TxD
Transmit Data
RxD
Receive Data
RTS
Request To Send
CTS
Clear To Send
DCD
Data Carrier Detect
DTR
Data Terminal Ready
DSR
Data Set Ready
HRS
Half Rate Select
RI
Ring Indicate
TxCLK IN Transmit Clock IN
TxCLK
Transmit Clock
RxCLK
Receive Clock
SGND
Signal Ground
FGND
Frame Ground
Appendix C. X.25 Cables and Connectors
259
C.2.1.3 X.21 Pin Assignment
Table 33. Portmaster and Multiport: X.21
Mnemonic
I/O
Port
0
Port
1
Port
2
Port
3
Port
4
Port
5
25-Position Connector
TxA
O
40
04
66
69
73
55
02
TxB
O
41
05
19
20
10
13
24
RxA
I
02
64
28
31
54
75
03
RxB
I
62
26
57
77
18
53
17
CxA
O
01
63
27
30
34
16
04
CxB
O
60
24
47
50
35
17
20
IxA
I
61
25
48
51
15
36
05
IxB
I
42
06
68
71
72
33
06
XxA
O
22
45
09
12
74
56
08
XxB
O
03
65
29
32
49
52
22
SxA
I
23
46
78
59
39
14
15
SxB
I
21
44
76
37
38
58
23
Ground
-
43
07
08
67
11
70
07
Note: x stands for port number
TxA, TxB
Transmit Data
RxA, RxB Receive Data
CxA, CxB Control
IxA, IxB
Indication
XxA, XxB Transmit Clock
SxA, SxB Receive Clock
C.2.2 Modem Attachment Pin Assignment
For modem pin assignments, see C.1.2, “X.25 Co-Processor Modem Attachment
Pin Assignment” on page 249.
260
RS/0000 X.25 Cookbook
C.2.3 X.25 Portmaster and Multiport Interconnection Cables
This sections shows the pin assignments for the Portmaster and Multiport to
modem interconnection cables.
C.2.3.1 X.21 Interface Cable - 6 Port Portmaster and Multiport
D-25 Connector
D-15 Connector
┌─────────────┐
┌─────────────┐
│ T(A)
2├──────────┤2
T(A) │
│ C(A)
4├──────────┤3
C(A) │
│ R(A)
3├──────────┤4
R(A) │
│ I(A)
5├──────────┤5
I(A) │
│ S(A)
15├──────────┤6
S(A) │
│ X(A)
8├──────────┤7
X(A) │
│ GND
7├──────────┤8
GND) │
│ T(B)
24├──────────┤9
T(B) │
│ C(B)
20├──────────┤10
C(B) │
│ R(B)
17├──────────┤11
R(B) │
│ I(B)
6├──────────┤12
I(B) │
│ S(B)
23├──────────┤13
S(B) │
│ X(B)
22├──────────┤14
X(B) │
└─────────────┘
└─────────────┘
Transmitted data (A)
Control (A)
Received data (A)
Indication (A)
Receive clock (A)
Transmit clock (A)
Signal ground
Transmitted data (B)
Control (B)
Received data (B)
Indication (B)
Receive clock (B)
Transmit clock (B)
Figure 66. X.21 Interface Cable
C.2.3.2 X.21bis/V.24 Interface Cable - 8 Port Portmaster and
Multiport
D-25 Connector
D-25 Connector
┌─────────────┐
┌─────────────┐
│ TXD
2├──────────┤2
TXD
│
│ RXD
3├──────────┤3
RXD
│
│ RTS
4├──────────┤4
RTS
│
│ CTS
5├──────────┤5
CTS
│
│ DSR
6├──────────┤6
DSR
│
│ GND
7├──────────┤7
GND
│
│ CD
8├──────────┤8
DSR
│
│ TX CLK
15├──────────┤15 TX CLC
│
│ RX CLK
17├──────────┤17 RX CLK
│
│ DTR
20├──────────┤20
DTR
│
│ DTECLK
24├──────────┤24 DTECLK
│
│ RI
22├──────────┤22
RI
│
│ HRS
23├──────────┤23
HRS
│
└─────────────┘
└─────────────┘
Transmitted Data
Received Data
Request to Send
Clear to Send
Data set ready
Signal ground
Carrier detect
Transmit clock in
Receive clock in
Data term. ready
DTE clock out
Ring Indicate
Half speed rec.
Figure 67. X.21bis/V.24 Interface Cable
Appendix C. X.25 Cables and Connectors
261
C.2.3.3 V.35 Interface Cable - 6 Port Portmaster and Multiport
D-25 Connector
M-34 Connector
┌─────────────┐
┌─────────────┐
│ GND
7├──────────┤B
GND
│
│ RTS
4├──────────┤C
RTS
│
│ CTS
5├──────────┤D
CTS
│
│ DSR
6├──────────┤E
DSR
│
│ CD
8├──────────┤F
CD
│
│ DTR
20├──────────┤H
DTR
│
│ DTECLK (A)24├──────────┤U DTECLK (A)│
│ DTECLK (B)11├──────────┤W DTECLK (B)│
│ TXD (A)
2├──────────┤P
TXD (A)│
│ RXD (A)
3├──────────┤R
RXD (A)│
│ TXD (B) 14├──────────┤S
TXD (B)│
│ RXD (B) 16├──────────┤T
RXD (B)│
│ RX CLK (A)17├──────────┤V RX CLK (A)│
│ TX CLK (A)15├──────────┤Y TX CLC (A)│
│ RX CLK (B) 9├──────────┤X RX CLK (A)│
│ TX CLK (B)12├──────────┤AA TX CLC (A)│
└─────────────┘
└─────────────┘
Signal ground
Request to Send
Clear to Send
Data set ready
Carrier detect
Data term. ready
DTE clock (A)
DTE clock (B)
Transmitted Data (A)
Received Data (A)
Transmitted Data (B)
Received Data (B)
Receive clock (A)
Transmit clock (A)
Receive clock (B)
Transmit clock (B)
Figure 68. X.21bis/V.35 Interface Cable
C.2.4 X.25 Portmaster, Multiport and ARTIC960 Diagnostic Wrap Plugs
This sections documents the pin assignments for the Portmaster, Multiport and
ARTIC960 adapter wrap plugs.
C.2.4.1 D-15 Wrap Plug: X.21
The D-15 wrap plug is used to test loopback at the DCE end of the X.21 interface
cable.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal
Pin no.
Pin no. Signal │
│ T(B)
9
11
R(B) │
│ T(A)
2
4
R(A) │
│ C(B)
10
12
I(B) │
│ C(A)
3
5
I(A) │
│ X(A)
7
6
S(A) │
│ X(B)
14
13
S(B) │
└───────────────────────────────────────────────┘
Figure 69. D-15 Wrap Plug
262
RS/0000 X.25 Cookbook
C.2.4.2 D-25 Wrap Plug: EIA 232 V.24
The D-25 wrap plug is used to test loopback at the DCE end of the X.21bis/V.24
interface cable.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal Pin no.
Pin no. Signal │
│ TXD
2
3
RXD
│
│ RTS
4 - 8
15 - 5
CTS
│
│ DTR
20 - 22 23 - 6
DSR
│
│ DTECLK 24
17
RXCLK │
│ RLBT
21
22
CI
│
└───────────────────────────────────────────────┘
Figure 70. D-25 Wrap Plug
PIN 8
DCD
Pin 15
TXCLKIN
Pin 22
RI
Pin 23
HRS
C.2.4.3 M/34 Wrap Plug: V.35
The M/34 wrap plug is used to test loopback at the DCE end of the X.21bis/V.35
interface cable.
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal Pin
Pin Signal
Pin Signal │
│ TXD(A) P - R RXD(A) - Y
TXCLK(A) │
│ TXD(B) S - T RXD(B) - AA TXCLK(B) │
│ RTS
C - D CTS
- F
DCD
│
│ Signal
Pin
Pin Signal
│
│ DTR
H E
DSR 6
│
│ DTECLK(A) U V
RXCLK(A)
│
│ DTECLK(B) W X
RXCLK(B)
│
└───────────────────────────────────────────────┘
Figure 71. M/34 Wrap Plug
C.2.4.4 D-25 Wrap Plug: X.21
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal
Pin no.
Pin no. Signal │
│ T(B)
2
3
R(B) │
│ T(A)
24
17
R(A) │
│ C(B)
4
5
I(B) │
│ C(A)
20
6
I(A) │
│ X(A)
8
15
S(A) │
│ X(B)
22
23
S(B) │
└───────────────────────────────────────────────┘
Figure 72. D-25 Wrap Plug
Appendix C. X.25 Cables and Connectors
263
C.2.4.5 D-25 Wrap Plug: V.35
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal Pin
Pin Signal
Pin Signal │
│ TXD(A) 2 - 3 RXD(A) - 15 TXCLK(A) │
│ TXD(B) 14 - 16 RXD(B) - 12 TXCLK(B) │
│ RTS
4 - 5 CTS
- 8 DCD
│
│ Signal
Pin
Pin Signal
│
│ DTR
20 6
DSR 6
│
│ DTECLK(A) 24 - 17
RXCLK(A)
│
│ DTECLK(B) 11 9
RXCLK(B)
│
└───────────────────────────────────────────────┘
Figure 73. D-25 Wrap Plug
C.2.4.6 D-37 Wrap Plug - 6 ARTIC960: V.36
The pin assignments are as follows:
┌───────────────────────────────────────────────┐
│ Signal Pin
Pin Signal
Pin Signal │
│ TXD(A) 4 - 6 RXD(A) - 5
TCLK(A) │
│ TXD(B) 22 - 24 RXD(B) - 23
TCLK(B) │
│ RTS
7 - 9 CTS
- 13 DCD
│
│ Signal
Pin
Pin Signal
│
│ DTR
12 - 11
DSR
│
│ TCLK(A)
17 8
RCLK(A)
│
│ TCLK(B)
35 - 26
RCLK(B)
│
└───────────────────────────────────────────────┘
Figure 74. D-37 Wrap Plug
264
RS/0000 X.25 Cookbook
C.2.4.7 D-78 Wrap Plug - 6 Port X.21
The pin assignments are as follows:
Figure 75. D-78 X.21 Wrap Plug
Appendix C. X.25 Cables and Connectors
265
C.2.4.8 D-100 Wrap Plug - 8 Port X.21
The pin assignments are as follows:
Figure 76. D-100 Wrap Plug
266
RS/0000 X.25 Cookbook
C.2.4.9 D-100 Wrap Plug - 8 Port V.24
The pin assignments are as follows:
Figure 77. D-100 V.24 Wrap Plug
Appendix C. X.25 Cables and Connectors
267
C.2.4.10 D-100 Wrap Plug - 6 Port V.35 and 6 Port V.36
The pin assignments are as follows:
Figure 78. D-100 V.36/V.35 Wrap Plug
268
RS/0000 X.25 Cookbook
Appendix D. CCITT Causes and Diagnostics
D.1 CCITT Clear and Reset Causes
The CCITT meanings for the clear cause codes are:
Table 34. List of CCITT Clear Causes
Hex
Dec
Meaning
00
01
03
05
09
0B
0D
11
13
15
19
21
29
80
00
01
03
05
09
11
13
17
19
21
25
33
41
128
Originated by the remote X.25 data terminal equipment (DTE)
Number busy
Incorrect facility request
Network congestion
Out of order
Access barred
Not obtainable
Remote procedure error
Local procedure error
RPOA out of order
Reverse charging acceptance not subscribed
Incompatible destination
Fast select acceptance not subscribed
80 through FF Not defined by CCITT, but used by SNA
The CCITT meanings for the reset cause codes are:
Table 35. List of CCITT Reset Causes
Hex
Dec
Meaning
00
01
03
05
07
09
0F
11
1D
80
00
01
03
05
07
09
15
17
29
128
Originated by the remote X.25 data terminal equipment (DTE)
Out of order
Remote procedure error
Local procedure error
Network congestion
Remote DTE operational
Network operational
Incompatible destination
Network out of order
Originated through FF DTE
D.2 CCITT Diagnostic Codes
Table 36 (Page 1 of 2). List of CCITT Diagnostic Codes
Hex
Dec
Meaning
00
01
02
10
11
12
13
14
15
16
0
1
2
16
17
18
19
20
21
22
Clear or reset generated during restart
Invalid P(S) in packet from DCE
Invalid P(R) in packet from DCE
Invalid packet type
Invalid packet from DCE in state r1
Invalid packet from DCE in state r2
Invalid packet from DCE in state r3
Invalid packet from DCE in state p1
Invalid packet from DCE in state p2
Invalid packet from DCE in state p3
 Copyright IBM Corp. 1996
269
Table 36 (Page 2 of 2). List of CCITT Diagnostic Codes
Hex
Dec
Meaning
17
18
19
1A
1B
1C
1D
20
21
22
23
24
25
26
27
28
29
2A
2B
2C
2D
30
31
32
33
34
35
40
41
42
43
44
45
46
47
48
49
4A
4B
4C
4D
4E
50
51
52
53
54
70
71
72
73
74
75
76
77
78
79
7A
80
23
24
25
26
27
28
29
32
33
34
35
36
37
38
39
40
41
42
43
44
45
48
49
50
51
52
53
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
80
81
82
83
84
112
113
114
115
116
117
118
119
120
121
122
128
Invalid packet from DCE in state p4
Invalid packet from DCE in state p5
Invalid packet from DCE in state p6
Invalid packet from DCE in state p7
Invalid packet from DCE in state d1
Invalid packet from DCE in state d2
Invalid packet from DCE in state d3
Packet not allowed
Unidentifiable packet received from DCE
Incoming call received on one-way channel
Clear or call packet received from DCE on a permanent virtual circuit (PVC)
Packet received on an unassigned logical channel
REJECT not subscribed to
Packet received from DCE was too short
Packet received from DCE was too long
Invalid general format identifier (GFI)
Restart packet received from DCE with non-zero logical channel identifier
Invalid fast-select packet received from DCE
Unauthorized interrupt confirmation
Interrupt packet received from DCE when acknowledgment was still outstanding
Unauthorized reject
Timer expired (or limit surpassed)
Time-out or retries reached on call response from DCE
Time-out or retries reached on clear response from DCE
Time-out or retries reached on reset response from DCE
Time-out or retries reached on restart response from DCE
Time expired fpr call deflection
Call setup clearing or registration problem
Facility/Registration code not allowed
Invalid facility parameter
Invalid called address
Address missing in incoming call from DCE
Invalid facility/registration length field
Incoming call barred
No logical channel available
Call collision
Duplicate facility requested
Non-zero address length in fast-select clear from DCE
Non-zero facility length in fast-select clear from DCE
Facility not provided when expected
Invalid CCITT-specified DTE facility
Minimum number of call redirections or call deflections exceeded
Miscellaneous
Improper cause code from DTE
Nonoctet aligned
Inconsistent Q-bit settings
NUI problem
International problem
Remote network problem
International protocol problem
International link out of order
International link busy
Transit network facility problem
Remote network facility problem
International routing problem
Temporary routing problem
Unknown called DNIC
Maintenance action (may also apply within a national network)
Reserved for DTE-defined diagnostic information
270
RS/0000 X.25 Cookbook
D.3 Product-Specific Diagnostic Codes
Table 37. List of Product-Specific Diagnostic Codes
Hex
Dec
Meaning
81
82
83
84
85
86
87
88
129
130
131
132
133
134
135
136
No listener for incoming call
No available LCN for call
User e r r o r
User call rejection
Call cleared before accept
Invalid call reference
Registration timer expired
Invalid link layer state
D.4 ISO 8208 Diagnostic Codes
Table 38. List of ISO 8208 Diagnostic Codes
Hex
Dec
Meaning
90
91
92
93
A0
A1
A2
A3
A4
A5
A6
A7
E0
E1
E2
E3
E4
E5
E6
E7
E8
E9
EA
EB
144
145
146
147
160
161
162
163
164
165
166
167
224
225
226
227
228
229
230
231
232
233
234
235
Timer expired or retransmission count surpassed
Timer expired or retransmission count surpassed on interrupt-confirm from DCE
T25 timer expired, for data packet transmission
Timer expired or retransmission count surpassed for reject
DTE-specific signals
DTE operational
DTE not operational (level 2) or no application listening (network)
DTE resource constraint
Fast select not subscribed
Invalid partially full data packet received from DCE
D-bit procedure not supported
Registration or cancellation confirmed
OSI Network Service Problem
Disconnection (transient condition)
Disconnection (permanent condition)
Connection rejection -- reason unspecified (transient condition)
Connection rejection -- reason unspecified (permanent condition)
Connection rejection -- quality of service not available (transient condition)
Connection rejection -- qualtity of service not available (permanent condition)
Connection rejection -- NSAP unreachable (transient condition)
Connection rejection -- NSAP unreachable (permanent condition)
Reset -- reason unspecified.
Reset -- congestion
Connection rejection -- NSAP address unkown (permanent condition)
D.5 SNA Diagnostic Codes
Table 39 (Page 1 of 3). List of SNA Diagnostic Codes
Hex
Dec
Meaning
00
0C
10
11
12
13
0
12
16
17
18
19
Normal initialization or termination
Invalid LLC type
Invalid packet type (general)
Invalid packet type for state r1
Invalid packet type for state r2
Invalid packet type for state r3
Appendix D. CCITT Causes and Diagnostics
271
Table 39 (Page 2 of 3). List of SNA Diagnostic Codes
Hex
Dec
Meaning
14
15
16
17
18
19
1A
1B
1C
1D
20
21
22
23
24
30
31
32
33
34
40
50
51
52
53
54
55
56
57
58
59
5A
5B
5D
60
61
62
63
64
65
66
69
70
71
72
73
74
75
76
77
78
79
7B
7F
80
81
82
83
84
20
21
22
23
24
25
26
27
28
29
32
33
34
35
36
48
49
50
51
52
64
80
81
82
83
84
85
86
87
88
89
90
91
93
96
97
98
99
100
101
102
105
112
113
114
115
116
117
118
119
120
121
123
127
128
129
130
131
132
Invalid packet type for state p1
Invalid packet type for state p2
Invalid packet type for state p3
Invalid packet type for state p4
Invalid packet type for state p5
Invalid packet type for state p6
Invalid packet type for state p7
Invalid packet type for state d1
Invalid packet type for state d2
Invalid packet type for state d3
DCE timer expired (general)
DCE timer expired: incoming call
DCE timer expired: clear indication
DCE timer expired: reset indication
DCE timer expired: restart indication
DTE timer expired: (general)
DTE timer expired: call request
DTE timer expired: clear request
DTE timer expired: reset request
DTE timer expired: restart request
Unassigned (general)
QLLC error: (general)
QLLC error: undefined C-field
QLLC error: unexpected C-field
QLLC error: missing I-field
QLLC error: undefined I-field
QLLC error: I-field too long
QLLC error: Frame reject received
QLLC error: Header invalid
QLLC error: Data received in wrong state
QLLC error: Time-out condition
QLLC error: Nr invalid
QLLC error: Recovery rejected or terminated
QLLC error: ELLC time-out condition
PSH error (general)
PSH error: sequence error
PSH error: header too short
PSH error: PSH format invalid
PSH error: command undefined
PSH error: protocol invalid
PSH error: data received in wrong state
PAD error: time-out condition
PAD error: (general)
PAD error: PAD access facility failure
PAD error: SDLC FCS error
PAD error: SDLC time-out
PAD error: SDLC frame invalid
PAD error: I-field too long
PAD error: SDLC sequence error
PAD error: SDLC frame aborted
PAD error: SDLC FRMR received
PAD error: SDLC response invalid
PAD error: invalid packet type
PAD error: PAD inoperable
DTE-specific (general)
DTE-specific: 8100_DPPX-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
272
RS/0000 X.25 Cookbook
Table 39 (Page 3 of 3). List of SNA Diagnostic Codes
Hex
Dec
Meaning
85
86
87
88
89
8A
8B
8C
8D
8E
8F
90
91
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
AA
AB
AC
AD
AE
B0
B1
C0
C1
C2
C3
C4
C5
C6
C7
D0
D1
D2
E0
E1
E2
E3
E4
E5
E6
E7
E8
E9
EA
EB
EC
ED
133
134
135
136
137
138
139
140
141
142
143
144
145
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
176
177
192
193
194
195
196
197
198
199
208
209
210
224
225
226
227
228
229
230
231
232
233
234
235
236
237
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
DTE-specific: INN_QLLC-specific
Network-specific
Network-specific: DDX-P RNR packet received
Packet not allowed (general)
Packet not allowed: invalid M-bit packet sequence
Packet not allowed: invalid packet type received
Packet not allowed: invalid packet on PVC
Packet not allowed: unassigned LC
Packet not allowed: diagnostic packet received
Packet not allowed: packet too short
Packet not allowed: packet too long
Packet not allowed: invalid GFI
Packet not allowed: not identifiable
Packet not allowed: not supported
Packet not allowed: invalid Ps
Packet not allowed: invalid Pr
Packet not allowed: invalid D-bit received
Packet not allowed: invalid Q-bit received
DTE-specific: (NPSI gate/date) (general)
DTE-specific: no LU-to-LU session
DTE-specific: (general)
DTE-specific: termination pending
DTE-specific: channel inoperative
DTE-specific: unauthorized interrupt confirmation
DTE-specific: unauthorized interrupt request
DTE-specific: PU (PVC) not available
DTE-specific: inactivity time-out
DTE-specific: incompatible line configuration
Resources: (general)
Resources: buffers depleted
Resources: PIU too long
Local procedure error (general)
Local procedure error: packet with LC=0 not received
Local procedure error: restart or diagnostic packet on LCI = x′000′
Local procedure error: incoming call received on wrong LC
Local procedure error: facility not subscribed to
Local procedure error: packet not restart or diagnostic on LCI = x ′000′
Local procedure error: facility parameters not supported
Local procedure error: facility not supported
Local procedure error: unexpected calling DTE
Local procedure error: invalid D-bit request
Local procedure error: reset indication on virtual call
Local procedure error: invalid protocol identifier
Local procedure error: connection identifier mismatch
Local procedure error: missing cause or diagnostic code
Appendix D. CCITT Causes and Diagnostics
273
D.5.1 List of Diagnostic Codes Used by xtalk
The following diagnostic codes are set up by the IBM-supplied application xtalk
when clearing connections:
Table 40. List of xtalk Diagnostic Codes
Hex
Dec
Meaning
F1
F4
241
244
Normal disconnection
Connection request rejected. This may be because the program is busy (already
connected to someone else), or because the other program is not listening.
D.5.2 Logical Channel States
This is the list of the CCITT logical channel states referred to in D.2, “CCITT
Diagnostic Codes” on page 269 and D.5, “SNA Diagnostic Codes” on page 271.
274
State
Meaning
d1
Flow control ready
d2
DTE reset request
d3
DCE reset indication
p1
Channel ready
p2
DTE call request
p3
DCE incoming call
p4
Data transfer
p5
Call collision
p6
DTE clear request
p7
DCE clear indication
r1
Packet level ready
r2
DTE restart request
r3
DCE restart indication
RS/0000 X.25 Cookbook
Appendix E. Facilities
Facilities allow the suscriber greater control of the X.25 environment. X.25
applications use facilities to take advantage of options in the network
subscription.
E.1 Supported Facilities for X.25 Communications
Several types of facilities may be requested in a call packet. Standard X.25
facilities are the most common, but you may also find non-X.25 facilities specific
to your network or CCITT-defined facilities to be used with the OSI network
services. Check with you network provider to see which facilities are available.
E.1.1 Defining Facilities
See 7.3, “Requesting the Use of a Facility with TCP/IP” on page 145 and 8.3.6.4,
“Defining X.25 Optional Facilities Profile” on page 168 to see how to define
facilities for TCP/IP and SNA interfaces.
E.1.2 Facilities Format
Non-standard facilities are preceded by a facility marker : 0x0000, 0x000FF or
0x000F. They are laid out as follows:
┌─────────────────────────────────────────────────────────────────┐
│
X.25 facilities
│
├─────────────────────────────────────────────────────────────────┤
│
0x0
│
├─────────────────────────────────────────────────────────────────┤
│
0x0
│
├─────────────────────────────────────────────────────────────────┤
│
non-X.25 facilities provided by the local network
│
├─────────────────────────────────────────────────────────────────┤
│
0x0
│
├─────────────────────────────────────────────────────────────────┤
│
0xFF
│
├─────────────────────────────────────────────────────────────────┤
│
non-X.25 facilities provided by the remote network
│
├─────────────────────────────────────────────────────────────────┤
│
0x0
│
├─────────────────────────────────────────────────────────────────┤
│
0x0F
│
├─────────────────────────────────────────────────────────────────┤
│
CCITT-specified DTE facilities
│
└─────────────────────────────────────────────────────────────────┘
Figure 79. Facilities Format
If any section is not required, both it and the preceding facility marker can be left
out.
Within each section, the facilities format is defined as a series of facility codes,
followed by a number of bytes of arguments.
The number of bytes of arguments is defined by the first two bits of the facility
code:
 Copyright IBM Corp. 1996
275
┌─┬───────────────┬───────┬───────┬───────┬───────┬───────┬───────┐
│0│
Class
│
│
└─┴───────────────┴───────┴───────┴───────┴───────┴───────┴───────┘
Figure 80. Facility Code Format
The class can have one of the following values:
00
Class A. This has a single byte parameter field
01
Class B. This has two bytes as a parameter
10
Class C. This has three bytes as a parameter
11
Class D. The next byte defines how long the parameter is
There is one special facility code, 0xFF, which is reserved for extension of the
facility codes. The octet following this one indicates an extended facility code
having the format A, B, C or D. Repetition of the facility code 0xFF is permitted
resulting in additional extensions.
E.1.3 Index of the Facilities
Use the following index to find the paragraph describing the facility you are
looking for.
Table 41. Index of Facilities
Value
276
RS/0000 X.25 Cookbook
Function
Param.
length
Reference
01
Fast Select / Reverse charging
1
E.2.7
02
Throughput class required
1
E.2.3
03
Closed User Group selection required
1
E.2.4
04
Charging Information - Requesting Service
1
E.2.9
08
Called line adress modified notification
1
E.2.14
09
Closed User Group with outgoing access selection
1
E.2.5
0A
Quality of Service Negotiation - Minimum throughput
class
1
E.3.3
0B
Expedited Data Negotiation
1
E.3.5
41
Bilateral Closed User Group selection required
2
E.2.6
42
Packet Size selection
2
E.2.1
43
Window Size selection
2
E.2.2
44
RPOA selection required (basic format)
2
E.2.13
49
Transit Delay Selection and Notification
2
E.2.16
C1
Charging information - Call Duration
variable
E.2.12
C2
Charging information - Segment Count
variable
E.2.11
C3
Call Redirection Notification
variable
E.2.15
C4
RPOA selection required (extended format)
variable
E.2.13
C5
Charging information - Monetary Unit
variable
E.2.10
C6
Network User Identification
variable
E.2.8
C9
Called Address Extension (OSI)
variable
E.3.2
CA
Quality of Service Negotiation - End-to-end transit delay
variable
E.3.4
CB
Calling Address Extension (OSI)
variable
E.3.1
E.2 X.25 Facilities
The following are the formats of the facilities.
E.2.1 Packet Size Selection
E.2.1.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x42
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
Reserved
│
Transmit packet size
│
├─┼──────────────────────────────┼────────────────────────────────┤
│2│
Reserved
│
Receive packet size
│
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 81. Packet Size Selection
0x42
Packet size selection.
Transmit packet size
Indicates the requested size for packets transmitted
from the calling DTE. Supported values are:
0x04 = 16 octets
0x05 = 32 octets
0x06 = 64 octets
0x07 = 128 octets
0x08 = 256 octets
0x09 = 512 octets
0x0A = 1024 octets
0x0B = 2048 octets
0x0C = 4096 octets
Receive packet size
Requested size for packets transmitted from the called
DTE. Supported values are the same as for the
transmitted packet size.
E.2.2 Window Size Selection
E.2.2.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x43
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
Reserved
│
Transmit window size
│
├─┼──────────────────────────────┼────────────────────────────────┤
│2│
Reserved
│
Receive window size
│
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 82. Window Size Selection
0x43
Window size selection
Transmit window size
Requested size for the window for packets transmitted
by the calling DTE. This represents the maximum
number of packets that can be received without an
acknowledgment. Values are in the range from 0x01 to
0x07 inclusive.
Appendix E. Facilities
277
Received window size
Requested size for the window for packets to be
transmitted by the called DTE. Values are in the range
from 0x01 to 0x07 inclusive.
E.2.3 Throughput Class
E.2.3.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x02
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│ Outgoing Throughput class │ Incoming Throughput Class
│
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 83. Throughput Class
0x02
Throughput class required.
Outgoing Throughput
Throughput class requested for data to be sent by the
calling DTE. Supported values are:
0x07 = 1200 bit/s
0x08 = 2400 bit/s
0x09 = 4800 bit/s
0x0A = 9600 bit/s
0x0B = 19200 bit/s
0x0C = 48000 bit/s
Incoming Throughput
Throughput class request for data sent from the called
DTE. Supported values are the same as for incoming
throughput class.
E.2.4 Closed User Group Selection
E.2.4.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x03
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
First BCD digit of CUG │
Second BCD digit of CUG │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 84. Closed User Group Selection (Basic Format)
Or
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x47
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
First BCD digit of CUG │
Second BCD digit of CUG │
├─┼──────────────────────────────┼────────────────────────────────┤
│2│
Third BCD digit of CUG │
Fourth BCD digit of CUG │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 85. Closed User Group Selection (Extended Format)
278
0x03 (0x47)
Closed User Group selection required (extended).
CUG
Indicates the value of a Closed User Group: 1 to 99 for the
basic format, 1 to 9999 for the extended format.
RS/0000 X.25 Cookbook
E.2.5 CUG with Outgoing Access
E.2.5.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x09
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
First BCD digit of CUG │
Second BCD digit of CUG │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 86. CUG with Outgoing Access (Basic Format)
or
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x48
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
First BCD digit of CUG │
Second BCD digit of CUG │
├─┼──────────────────────────────┼────────────────────────────────┤
│2│
Third BCD digit of CUG │
Fourth BCD digit of CUG │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 87. CUG with Outgoing Access (Extended Format)
0x09 (0x48)
Closed User Group with outgoing access (extended).
CUG
Indicates the value of a closed user group. 1 to 99 for the
basic format, 1 to 9999 for the extended format.
E.2.6 Bilateral Closed User Group Selection
E.2.6.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x41
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
First BCD digit of CUG │
Second BCD digit of CUG │
├─┼──────────────────────────────┼────────────────────────────────┤
│2│
Third BCD digit of CUG │
Fourth BCD digit of CUG │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 88. Bilateral Closed User Group Selection
0x41
Bilateral Closed User Group selection required.
CUG
Indicates the value of a Closed User Group (1 to 9999).
E.2.7 Reverse Charging and Fast Select
E.2.7.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x01
│
├─┼───────────────┬───────┬───────┬───────┬───────┬───────┬───────┤
│1│
A
│
│ B │
└─┴───────────────┴───────┴───────┴───────┴───────┴───────┴───────┘
Figure 89. Reverse Charging and Fast Select
Appendix E. Facilities
279
0x01
Fast Select.
A
Indicates whether a restricted response is required when fast select
is also requested. Valid values are:
B
00
Fast select not selected
01
Fast select selected
10
Fast select requested with no restriction on response
11
Fast select requested with restriction on response
Reverse charge required; valid values are:
0
No reverse charging requested
1
Reverse charging requested
E.2.8 Network User Identification
E.2.8.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC6
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of Network User Identification
│
├─┼───────────────────────────────────────────────────────────────┤
│2│
│
├─┤
Network User Identification
│
│*│
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 90. Network User Identification
0xC6
Network user identification.
Length of NUI
The number of bytes given in network user
identification data.
NUI data
Network user identification data in format identified by
the network administrator.
E.2.9 Charging Information Request
E.2.9.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x04
│
├─┼───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┤
│1│
│ A │
└─┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┘
Figure 91. Charging Information Request
0x04
Charging Information - Requesting Service
can be one of:
280
RS/0000 X.25 Cookbook
0
Charging information not requested
1
Charging information requested
E.2.10 Charging (Monetary Unit)
E.2.10.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC5
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of charging information
│
├─┼───────────────────────────────────────────────────────────────┤
│2│
│
├─┤
Charging Identification
│
│*│
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 92. Charging (Monetary Unit)
0xC5
Charging information - monetary unit
Length of Charging Info
Number of bytes of the charging information
Charging Identification
Charging information - monetary unit data
E.2.11 Charging (Segment Count)
E.2.11.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC2
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of charging information
│
├─┼───────────────────────────────────────────────────────────────┤
│2│
│
├─┤
Charging Identification
│
│*│
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 93. Charging (Segment Count)
0xC2
Charging information - segment count
Charging Identification
Charging information - segment count data
E.2.12 Charging (Call Duration)
E.2.12.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC1
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of charging information
│
├─┼───────────────────────────────────────────────────────────────┤
│2│
│
├─┤
Charging Identification
│
│*│
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 94. Charging (Call Duration)
0xC1
Charging information - call duration
Appendix E. Facilities
281
Length of Charging Info
Length in bytes of charging information
Charging Identification
Charging information - call duration data
E.2.13 RPOA Selection
E.2.13.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x44
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│
First BCD digit of RPOA │
Second BCD digit of RPOA │
├─┼──────────────────────────────┼────────────────────────────────┤
│2│
Third BCD digit of RPOA │
Fourth BCD digit of RPOA │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 95. RPOA Selection (Basic Format)
Or
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC4
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of RPOA information
│
├─┼──────────────────────────────┬────────────────────────────────┤
│2│ First BCD digit of RPOA #1 │
Second BCD digit of RPOA #1 │
├─┼──────────────────────────────┼────────────────────────────────┤
│3│ Third BCD digit of RPOA #1 │
Fourth BCD digit of RPOA #1 │
├─┼──────────────────────────────┼────────────────────────────────┤
│*│ First BCD digit of RPOA #n │
Second BCD digit of RPOA #n │
├─┼──────────────────────────────┼────────────────────────────────┤
│*│ Third BCD digit of RPOA #n │
Fourth BCD digit of RPOA #n │
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 96. RPOA Selection (Extended Format)
0x44 (0xC4)
Recognized private operating agency selection
required.
RPOA
Indicates the requested RPOA transit network
identification code, 1 to 9999.
Length of RPOA info.
Length in bytes of the RPOA information in the facility.
E.2.14 Called Line Address Modified Notification
E.2.14.1 Coding in the Call Packet
When the redirection is done by the DCE:
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x08
│
├─┼───────┬───────┬───────┬───────┬───────────────────────────────┤
│1│ 0 │
│
A
│
└─┴───────┴───────┴───────┴───────┴───────────────────────────────┘
Figure 97. Called Line Address Modified Notification
282
0x08
Called line address modified notification
A
Can have one of the following values:
RS/0000 X.25 Cookbook
0x7
Call distribution within a hunt group
0x1
Call redirection due to original DTE busy
0x9
Call redirection due to original DTE out of order
0x0F
Call redirection due to prior request from originally called
DTE for systematic redirection
Or, when the redirection is DTE originated:
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x08
│
├─┼───────┬───────────────────────────────────────────────────────┤
│1│ 1 │
B
│
└─┴───────┴───────────────────────────────────────────────────────┘
Figure 98. Called Line Address Modified Notification (CLAMN)
0x08
Called Line Address Modified Notification.
B
Passed from the remote DTE, gives a reason for the redirection.
E.2.15 Call Redirection Notification
E.2.15.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC3
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of redirection information
│
├─┼───────────────────────────────────────────────────────────────┤
│2│
Call redirection reason
│
├─┼──────────────────────────────┬────────────────────────────────┤
│3│
│
Length of called address
│
├─┼──────────────────────────────┴────────────────────────────────┤
│4│
│
├─┤
Called Address
│
│*│
(BCD)
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 99. Call Redirection Notification
0xC3
Call Redirection Notification.
Call redirection reason
Contains reason for call redirection.
Call redirection address
0x1
Call redirection due to original DTE busy
0x9
Call redirection due to original DTE out of
order
0x0F
Call redirection due to prior request from
originally called DTE for systematic
redirection
The original called DTE address coded in BCD.
Appendix E. Facilities
283
E.2.16 Transit Delay Selection and Indication
E.2.16.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x49
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
│
├─┤
Transit delay in milliseconds
│
│2│
( in binary, hi byte first )
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 100. Transit Delay Selection and Indication
0x49
Transit delay selection and notification
Transit delay
Transit delay in milliseconds
E.3 CCITT Specified Facilities to Support the OSI Network
The following facilities are defined for OSI networks.
E.3.1 Calling Address Extension
E.3.1.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xCB
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Number of bytes following
│
├─┼───────────────┬───────────────────────────────────────────────┤
│2│
Use
│
Length of calling extension address
│
├─┼───────────────┴───────────────────────────────────────────────┤
│3│
│
├─┤
Calling extension address
│
│*│
(BCD)
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 101. Calling Address Extension
0xCB
Calling address extension
Use
May may have the following values:
00
To carry an entire calling OSI NSAP
address
01
To carry a partial calling OSI NSAP address
10
To carry a non-OSI calling address
11
Reserved
Calling extension address Up to 40 decimal digits coded in BCD containing the
calling address extension
284
RS/0000 X.25 Cookbook
E.3.2 Called Address Extension
E.3.2.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xC9
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Number of bytes following
│
├─┼───────────────┬───────────────────────────────────────────────┤
│2│
Use
│
Length of called extension address
│
├─┼───────────────┴───────────────────────────────────────────────┤
│3│
│
├─┤
Called extension address
│
│*│
(BCD)
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 102. Called Address Extension
0xC9
Called address extension
Use
Values as above
Called address extension Up to 40 decimal digits containing the called address
extension coded in BCD
E.3.3 Minimum Throughput Class
E.3.3.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x0A
│
├─┼──────────────────────────────┬────────────────────────────────┤
│1│ Calling minimum throughput │ Called minimum throughput
│
└─┴──────────────────────────────┴────────────────────────────────┘
Figure 103. Minimum Throughput Class
0x0A
Quality of Service Negotiation - minimum throughput
class
Calling min throughput
Throughput class requested for data to be sent by the
calling DTE. Supported values are:
0x07 = 1200 bit/s
0x08 = 2400 bit/s
0x09 = 4800 bit/s
0x0A = 9600 bit/s
0x0B = 19200 bit/s
0x0C = 48000 bit/s
Called min throughput
Throughput class request for data sent from the called
DTE. Supported values are the same as for the calling
minimum throughput class.
Appendix E. Facilities
285
E.3.4 End-to-End Transmit Delay Facility
E.3.4.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0xCA
│
├─┼───────────────────────────────────────────────────────────────┤
│1│
Length of the following area
│
├─┼───────────────────────────────────────────────────────────────┤
│2│
│
├─┤
Cumulative transit delay in milliseconds
│
│3│
( in binary, hi byte first )
│
├─┼───────────────────────────────────────────────────────────────┤
│4│
│
├─┤
Requested end─to─end delay in milliseconds
│
│5│
( in binary, hi byte first )
│
├─┼───────────────────────────────────────────────────────────────┤
│6│
│
├─┤
Maximum acceptable transit delay in milliseconds
│
│7│
( in binary, hi byte first )
│
└─┴───────────────────────────────────────────────────────────────┘
Figure 104. End-to-End Transmit Delay Facility
0xCA
Quality of Service Negotiation - End-to-end transit
delay.
Length
The number of values in the stream. This can be one
of 1, 2 or 3, as the requested end-to-end delay and
maximum acceptable transit delay are optional.
Req end to end delay
Specifies cumulative, requested end-to-end and
maximum acceptable transit delays.
E.3.5 Expedited Data Negotiation
E.3.5.1 Coding in the Call Packet
┌─┬───────────────────────────────────────────────────────────────┐
│0│
0x0B
│
├─┼───────┬───────┬───────┬───────┬───────┬───────┬───────┬───────┤
│1│
│ A │
└─┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┘
Figure 105. Expedited Data Negotiation
286
0x0B
Expedited Data Negotiation
A
Can be one of:
RS/0000 X.25 Cookbook
0
No use of expedited data
1
Use of expedited data
Appendix F. PAD Parameters and Commands
F.1 PAD Parameters
For more detailed descriptions of the PAD parameters, see Table 43 on
page 289.
Table 42 (Page 1 of 3). User-Customizable PAD Parameters Defined in X.3
Number
Name
Value
Meaning
1
PAD recall
0
1
32-126
Data flow may not be interrupted, you cannot enter PAD
commands
The escape character is DLE
Value of the PAD recall character in decimal
2
Echo
0
1
No echo by the PAD
Local echo by the PAD
3
Data
forwarding
signal
0
1
2
4
6
8
16
18
32
64
126
Data forwarding not controlled by a character
Alphanumeric characters (A-Z, a-z, 0-9)
Character CR
Characters ESC, BEL, ENQ, ACK
Characters CR, ESC, BEL, ENQ, ACK
Characters DEL, CAN, DC2
Characters ETX, EOT
Characters CR, ETX, EOT
Characters HT, LF, VT, FF
All other characters in column 0 and 1 not included in
above
Any character in column 0 and 1, or DEL character
4
Idle timer delay
0
1-255
No timeout period is used
Timeout period expressed in units of 0.05 seconds
5
Ancillary device
control
0
1
2
No use of X-ON (DC1) and X-OFF (DC3) flow control
Use X-ON and X-OFF (during data transfer)
Use X-ON and X-OFF (during data and command
transfer)
6
PAD service
signals
0
16
32
48
No service signals are sent to the terminal (start-stop
mode DTE)
Service signals other than prompt PAD service are
transmitted in standard format
Service signal prompt PAD service is transmitted in
standard format
PAD service signals are transmitted in a
network-dependent format
English extended dialogue mode
French extended dialogue mode
Spanish extended dialogue mode
1
4
8-15
 Copyright IBM Corp. 1996
7
Action of PAD
on break signal
0
1
2
3
4
5
6
7
8
9-15
16
17-31
Nothing
Send interrupt packet to correspondent
Reset
= 1 + 2
Send to DTE indication of break PAD message
= 1 + 4
= 2 + 4
= 1 + 2 + 4
Escape from data transfer state
Formed from combination of 1, 2, 4, 8
Discard output to terminal
Formed from combination of 1, 2, 4, 8, 16
8
Discard output
0
1
Normal data delivery to terminal
Discard all output to terminal
287
Table 42 (Page 2 of 3). User-Customizable PAD Parameters Defined in X.3
Number
Name
Value
Meaning
9
Padding after
carriage return
0
1-255
No padding after CR in datastream sent to terminal
Specified number of padding characters inserted after
CR in datastream sent to terminal
10
Line folding
0
1-255
No line folding
Line folding after the specified number of consecutive
printable characters
11
(read
only)
Line speed
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
110 bit/s
134.5 bit/s
300 bit/s
1200 bit/s
600 bit/s
75 bit/s
150 bit/s
1800 bit/s
200 bit/s
100 bit/s
50 bit/s
75/1200 bit/s (outbound/inbound)
2400 bit/s
4800 bit/s
9600 bit/s
19200 bit/s
48000 bit/s
56000 bit/s
64000 bit/s
12
Flow control of
the PAD
0
1
No use of X-ON and X-OFF
Use of X-ON and X-OFF
13
Linefeed after
carriage return
0
1
2
3
4
5
6
7
No linefeed
Insertion in
Insertion in
= 1 + 2
Insertion in
= 1 + 4
= 2 + 4
= 1 + 2 +
0
No padding characters inserted after LF sent to
terminal, in data transer state
Specified number of padding characters inserted after
LF sent to terminal, in data transfer state
14
Padding after
linefeed
1-255
datastream after echo of CR to terminal
4
15
Editing
0
1
No use of editing in data transfer state
Use of editing in data transfer state
16
Character
delete
0-127
International Alphabet 5 (IA5) character that causes
character delete
17
Line delete
0-127
IA5 character that causes line delete
18
Line display
0-127
IA5 character that causes line display
19
Editing PAD
service signals
0
1
2
8,
32-126
No editing of PAD service signals
Editing for printing terminals
Editing for display terminals
Editing using a character from IA5
20
Echo mask
0
1
2
4
8
16
32
64
All characters echoed (no mask)
No echo of CR
No echo of LF
No echo of VT, HT and FF
No echo of BEL, BS
No echo of ESC, ENQ
No echo of ACK, NAK, STX, SOH, EOT, ETB, ETX
No echo of editing characters designated by parameters
16-18 above
No echo of all other characters in columns 0 and 1 not
mentioned above and DEL
128
288
insertion
datastream to terminal
datastream from terminal
RS/0000 X.25 Cookbook
Table 42 (Page 3 of 3). User-Customizable PAD Parameters Defined in X.3
Number
Name
Value
Meaning
21
Parity
treatment
0
1
2
3
No parity checked or generated
Parity checking
Parity generation
= 1 + 2
22
Page wait
0
1-255
Page wait disabled
Number of line feed characters considered by the PAD
for the page wait function
F.2 Detailed Description of PAD Parameters
Table 43 (Page 1 of 2). Detailed Descriptions of PAD Parameters Defined in X.3
Number
Name
Explanation
1
PAD recall
This parameter specifies the character that a user can type at the
terminal to interrupt the data flow with the X.25 host and send
commands to the PAD.
Note: If this parameter value is changed to 0, the user will no
longer be able to change PAD parameters.
2
Echo
This parameter specifies whether characters received from the
terminal are to be transmitted back to the terminal, as well as
being interpreted by the PAD.
When working in line mode, this parameter should be set to 1 to
get an echo from the PAD, and the echo provided by the host
should be disabled with the stty -echo command.
3
Data
forwarding
signal
This parameter specifies the conditions under which a string of
input characters from a terminal will be converted to a data
packet and forwarded over the network, as defined in X.25.
If this parameter is set to 0, every character typed at the terminal
is sent by the PAD in an individual packet. For the other settings,
the PAD acts as a buffer and sends a packet only when the
specified character is entered. If the terminal is in line mode, for
example entering UNIX commands, this parameter may be set to
18. Thus, packets will only be sent to the host on pressing Enter,
Ctrl-C or Ctrl-D.
4
Idle timer delay
This parameter specifies a time-out period for the reception of
characters from the terminal. After this time-out expires,
characters already received by the PAD are formatted into a
packet and sent across the X.25 network.
If using line mode, this parameter would be set to 0. When a
non-zero value is used, this parameter can improve the
performance of applications transferring data from the terminal to
the host, as the time delay between the PAD receiving two
consecutive characters is lower than the time-out period. The PAD
accumulates the data and only sends it when it has a full packet
or when the file transfer application has stopped sending
characters.
5
Ancillary device
control
This parameter allows for flow control between the PAD and the
terminal. The PAD indicates whether or not it is ready to accept
characters from the terminal by transmitting special characters
(the IA5 characters used to switch an ancillary transmitting device
on and off).
6
PAD service
signals
This parameter determines whether or not, and in what format,
PAD service signals are transmitted. It controls the service
signals and the dialogue mode for the terminal.
7
Action of PAD
on break signal
This parameter specifies the action to be taken by the PAD when
it receives a break signal from the terminal.
Appendix F. PAD Parameters and Commands
289
Table 43 (Page 2 of 2). Detailed Descriptions of PAD Parameters Defined in X.3
Number
Name
Explanation
8
Discard output
This parameter determines whether data should be disassembled
and transmitted to the terminal, or discarded.
9
Padding after
carriage return
This parameter determines if the PAD will automatically add
padding characters into the character stream being sent to the
terminal after receiving a CR.
10
Line folding
This parameter determines how many characters can be sent to
the terminal without inserting an appropriate formatting character.
11
Line speed
This parameter indicates the line speed at which the terminal is
attached to the PAD. This parameter cannot be changed; it can
only be read.
12
Flow control of
the PAD
This parameter allows for the control of flow between the terminal
and the PAD. The terminal indicates whether or not it is ready to
accept characters from the PAD by transmitting special
characters, which in IA5 are used to switch ancillary transmitting
devices on and off.
13
Linefeed after
carriage return
This parameter provides for the automatic insertion, by the PAD,
of a linefeed character into the character stream to or from the
terminal, or after each CR character. This function only applies in
the data transfer state.
14
Padding after
linefeed
This parameter determines if the PAD will automatically add
padding characters into the character stream being sent to the
terminal after a linefeed character. This function only applies in
the data transfer state.
15
Editing
This parameter controls the use of local editing in the PAD
command state and the data transfer state. During the PAD
command state, the editing function is always available. For
example, the terminal is able to edit the PAD command signals
sent to the PAD before they are processed.
Parameters 15 - 19 control these editing functions.
16
Character
delete
This parameter determines the character from the IA5 that is to
request character deletion for the PAD editing buffer.
17
Line delete
This parameter determines the character from the IA5 that causes
the PAD to delete the contents of its edit buffer.
18
Line display
This parameter determines the character from the IA5 that causes
the PAD to display the contents of its edit buffer.
19
Editing PAD
service signals
This parameter controls how the PAD service signals can be
edited.
20
Echo mask
This parameter selects which characters are echoed if local echo
is enabled.
21
Parity
treatment
This parameter allows the PAD to check parity in the data stream
from the terminal and/or generate parity on the data stream to the
terminal.
22
Page wait
This parameter controls screen scrolling. It allows the PAD to
suspend the transmission of characters to the terminal after a
specified number of linefeed characters have been sent from the
PAD.
F.3 Commands Entered from the PAD Prompt
Table 44 (Page 1 of 2). Commands that can be Issued from the PAD Prompt
290
PAD command
Explanation
BREAK
Send a break character to the PAD.
RS/0000 X.25 Cookbook
Table 44 (Page 2 of 2). Commands that can be Issued from the PAD Prompt
PAD command
Explanation
CALL
Establish a connection to the remote X.25 host
( call 3106010761)
CLEAR
Clear the connection with the remote X.25 host. The clear is sent from the
PAD immediately - see ICLEAR.
HELP
Request help text, see 5.3.2, “PAD Commands” on page 97 for more
details.
ICLEAR
Sends an invitation to clear to the remote X.25 DTE. This allows the
remote host to send any pending data before clearing the call.
INTERRUPT
Send an interrupt packet. The packet contents cannot be user specified.
LANGUAGE
Set the language for PAD help text to English, French or Spanish.
( language french)
NUI
This command is not implemented in the PAD.
PAR
Read the PAD parameters.
PAR?
Displays all parameters
PAR? 2, 3
Displays parameter 2 and 3
In advanced mode, READ or PARAMETER can be used instead of PAR
PROFILE
Displays which profiles are available, or to change the profile enter
PROFILE followed by the profile name, for example, PROFILE PROFILE_51
READ
See PAR above
RREAD
READ function for remote PAD
RSET
SET function for remote PAD
SET
Sets one or more of the PAD parameters:
set 2:1, 14:2
or in advanced mode
set echo:1, lfpad:2
Note: The default profile does not allow the parameters to be changed
locally, as they are being controlled remotely through the TTY subsystem
and the stty command.
STATUS
Gives whether a connection to the remote X.25 host is active. Returns
ENGAGED if it is active or FREE if the connection has not been established.
Appendix F. PAD Parameters and Commands
291
F.4 Messages from the PAD to the Terminal
Just as the user can send commands to the PAD, the PAD can send indications
to the user. These indications are called PAD service signals. The PAD service
signals are summarized in the following table.
Table 45. Service Signals Sent from the X.3 PAD to the X.28 Terminal
PAD service signal
Explanation
COM
Call successful
CLR OCC
The called DTE is occupied
CLR NC
N e t w o r k congestion
CLR INV
Invalid facility
CLR NA
Access barred (for example because of CUG)
CLR ERR
Local procedure error
CLR RPE
Remote procedure error
CLR NP
Called number does not exist
CLR DER
The called number is out of order
CLR PAD
The call has been cleared as an answer to an invitation to clear from the remote DTE
CLR DTE
The remote DTE has cleared the call
CLR CONF
Clear confirmation (response to CLR PAD command)
RESET DTE
Remote DTE
RESET ERR
Local procedure error
RESET NC
N e t w o r k congestion
ERROR
Error in PAD command
XXX
Line delete function complete
292
RS/0000 X.25 Cookbook
Appendix G. CIO and X.25 Device Driver Error Codes
 Copyright IBM Corp. 1996
Symbol
Hex.
Dec.
Cause
CIO OK
00
00
Operation was successful
CIO BAD_MICROCODE
01
01
Invalid microcode
CIO BUF_OVFLW
02
02
Data too large for buffer
CIO HARD_FAIL
03
03
H a r d failure
CIO LOST_DATA
04
04
Data were lost
CIO N O M B U F
05
05
No mbuf available
CIO NOT_STARTED
06
06
Start not performed
CIO TIMEOUT
07
07
Operation timed out
CIO NET_RCVRY_ENTER
08
08
Enter network recovery
CIO NET_RCVRY_EXIT
09
09
Exit network recovery
CIO NET_RCVRY_MODE
0A
10
Network recovery mode
CIO INV_CMD
0B
11
Invalid command
CIO BAD_RANGE
0C
12
Bad address range
CIO NETID_INV
0D
13
Invalid net ID
CIO NETID_DUP
0E
12
Duplicate net ID
CIO NETID_FULL
0F
15
All net are used
CIO TX_FULL
10
16
Transmit queue is full
X25 BAD_CALL_ID
41
65
The X.25 Reject operation completed
X25 CLEAR
42
66
The session has been closed
X25 INV_CTR
43
67
The counter is invalid
X25 NAME_USED
44
68
The name is already being listened to
X25 NOT_PVC
45
69
Not defined as a Permanent Virtual Circuit
(PVC)
X25 NO_ACK
46
70
No acknowledgement has been issued
X25 NO_ACK_REQ
47
71
No packets currently require
acknowledgement
X25 NO_LINK
48
72
The link is not configured or could not be
connected
X25 NO_NAME
49
73
There is no such name in the routing list
X25 PROTOCOL
4A
74
An X.25 protocol error occurred, probably
caused by trying to transmit data on a
circuit which has already been cleared
X25 PVC_USED
4B
75
The Permanent Virtual Circuit (PVC) has
already been allocated
X25 RESET
4C
76
The virtual circuit has been reset
X25 TABLE
4D
77
Could not update routing list
X25 TOO_MANY_VCS
4E
78
No virtual circuits are free on the port
X25 AUTH_LISTEN
4F
79
You cannot listen to this name because the
routing list entry has a userid which
excludes the user running the application
X25 BAD_PKT_TYPE
50
80
Invalid packet type
X25 BAD_SESSION_TYPE
51
81
293
294
RS/0000 X.25 Cookbook
Appendix H. Country Networks Default Parameters
Table 46. Default Parameters for the Various Networks
Country
Code
Network
Conn.
Mode
CCITT
Support
Thruput
Range
Packet
Range
Argentina
Australia
Austria
Austria
Belgium
Brazil
Canada
Canada
Chile
China
De n m a r k
De n m a r k
Egypt
Finland
Finland
France
Greece
Hong Kong
Iceland
Indonesia
Ireland
Israel
Italy
Japan
Korea
Luxembourg
Malasia
Mexico
Netherlands
N e w Zealand
Norway
Portugal
Singapore
South Africa
Spain
Sweden
Switzerland
Turkey
UK*
USA
USA
USA
Germany
Germany
Yugoslavia
722
505
232
232
206
724
302
302
730
460
238
238
602
244
244
208
202
454
274
510
272
425
222
440
450
270
502
334
204
530
242
268
525
655
214
240
228
286
234-5
310-6
310-6
310-6
218
218
220
Other public
Other public
DATEX
Other public
Other public
Other public
DATAPAC
Other public
Other public
Other public
DATAPAC
Other public
Other public
DATAPAC
Other public
Other public
Other public
DATAPAC
Other public
Other public
Other public
Other public
Other public
Other public
Other public
Other public
Other public
Other public
Other public
Other public
DATAPAC
Other public
Other public
Other public
Other public
DATAPAC
Other public
Other public
Other public
DDN
Other public
TELENET
DATEX
Other public
Other public
Passive
Active
Passive
Passive
Passive
Active
Passive
Passive
Active
Active
Active
Passive
Active
Active
Active
Active
Active
Passive
Active
Active
Passive
Passive
Passive
Active
Active
Active
Passive
Passive
Active
Active
Passive
Passive
Passive
Active
Passive
Passive
Passive
Passive
Passive
Active
Active
Active
Passive
Active
Passive
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1984
1984
1984
1980
1984
1984
1980
1980
1984
1984
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1984
1980
75-48000
75-48000
300-9600
300-9600
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
75-48000
16-1024
16-1024
64-512
64-512
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
64-512
16-4096
16-4096
16-1024
16-4096
16-4096
16-1024
16-1024
16-4096
64-512
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-1024
16-4096
16-1024
DATAPAC
DATEX
DDN
TELENET
Other public
Passive
Passive
Active
Active
Active
1980
1980
1980
1980
1980
75-48000
75-48000
75-48000
75-48000
75-48000
16-1024
16-1024
16-1024
16-1024
16-1024
Others
*: Also first incoming SVC set to 512, first 2-way SVC set to 1024, first outgoing SVC set to
1536.
 Copyright IBM Corp. 1996
295
296
RS/0000 X.25 Cookbook
Appendix I. Special Notices
This publication is intended to help customers and systems engineers install,
customize and use X.25 support of the RISC System/6000. The information in
this publication is not intended as the specification of any programming
interfaces that are provided by AIX/6000, AIXLink/X.25, AIX X.25 or AIX SNA
Services. See the PUBLICATIONS section of the IBM Programming
Announcement for AIX/6000, AIXLink/X.25, AIX X.25 or SNA Services for the RISC
System/6000 for more information about what publications are considered to be
product documentation.
References in this publication to IBM products, programs or services do not
imply that IBM intends to make these available in all countries in which IBM
operates. Any reference to an IBM product, program, or service is not intended
to state or imply that only IBM′s product, program, or service 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, program or service.
Information in this book was developed in conjunction with use of the equipment
specified, and is limited in application to those specific hardware and software
products and levels.
IBM may have
this document.
these patents.
Licensing, IBM
patents or pending patent applications covering subject matter in
The furnishing of this document does not give you any license to
You can send license inquiries, in writing, to the IBM Director of
Corporation, 500 Columbus Avenue, Thornwood, NY 10594 USA.
Licensees of this program who wish to have information about it for the purpose
of enabling: (i) the exchange of information between independently created
programs and other programs (including this one) and (ii) the mutual use of the
information which has been exchanged, should contact IBM Corporation, Dept.
600A, Mail Drop 1329, Somers, NY 10589 USA.
Such information may be available, subject to appropriate terms and conditions,
including in some cases, payment of a fee.
The information contained in this document has not been submitted to any
formal IBM test and is distributed AS IS. The information about non-IBM
(″vendor″) products in this manual has been supplied by the vendor and IBM
assumes no responsibility for its accuracy or completeness. The use of this
information or the implementation of any of these techniques is a customer
responsibility and depends on the customer′s ability to evaluate and integrate
them into the customer′s operational environment. While each item may have
been reviewed by IBM for accuracy in a specific situation, there is no guarantee
that the same or similar results will be obtained elsewhere. Customers
attempting to adapt these techniques to their own environments do so at their
own risk.
Any performance data contained in this document was determined in a
controlled environment, and therefore, the results that may be obtained in other
operating environments may vary significantly. Users of this document should
verify the applicable data for their specific environment.
 Copyright IBM Corp. 1996
297
The following terms are trademarks of the International Business Machines
Corporation in the United States and/or other countries:
AIX
AIXwindows
APPN
BookMaster
IBM
NetView
PS/2
RS/6000
S/390
System/390
VTAM
AIX/6000
AnyNet
BookManager
C Set ++
Micro Channel
Portmaster
RISC System/6000
S/370
SAA
Systems Application Architecture
XWindow System
The following terms are trademarks of other companies:
PC Direct is a trademark of Ziff Communications Company and is used by IBM
Corporation under license.
UNIX is a registered trademark in the United States and other countries licensed
exclusively through X/Open Company Limited.
C-bus is a trademark of Corollary, Inc.
Microsoft, Windows, and the Windows 95 logo are trademarks or registered
trademarks of Microsoft Corporation.
Java and HotJava are trademarks of Sun Microsystems, Inc.
BSC
CA
DCE
Digital, VT
SCSI
ADD
SMS
AFS
ODM
TI
DCA
MS
DynaText
Geneva
Network File System, NFS
X-Windows
Intel,80186
BusiSoft Corporation
Computer Associates
The Open Software Foundation
Digital Equipment Corporation
Security Control Systems, Incorporated
Applications Design and Development,
Incorporated
Standard Microsystems Corporation
Transarc Corporation
Optical Disk Mastering, Incorporated
Texas Instruments, Incorporated
Digital Communications Associates,
Incorporated
Microsoft Corporation
Electronic Book Technologies,
Incorporated
Apple Computer, Incorporated
Sun Microsystems, Inc.
Massachusetts Institute of Technology
Intel
Other trademarks are trademarks of their respective companies.
298
RS/0000 X.25 Cookbook
Appendix J. Related Publications
The publications listed in this section are considered particularly suitable for a
more detailed discussion of the topics covered in this redbook.
J.1 International Technical Support Organization Publications
For information on ordering these ITSO publications see “How To Get ITSO
Redbooks” on page 303.
•
International Technical Support Organization Bibliography of Redbooks,
GG24-3070.
To get listings of ITSO technical publications (known as “redbooks”) online,
VNET users may type:
TOOLS SENDTO WTSCPOK TOOLS REDBOOKS GET REDBOOKS CATALOG
How to Order ITSO Technical Publications
IBM employees in the USA may order ITSO books and CD-ROMs using
PUBORDER. Customers in the USA may order by calling 1-800-879-2755 or by
faxing 1-800-284-4721. Visa and Master Cards are accepted. Outside the
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Customers may order hardcopy ITSO books individually or in customized
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employees and customers may also order ITSO books in online format on
CD-ROM collections, which contain books on a variety of products.
J.2 Redbooks on CD-ROMs
Redbooks are also available on CD-ROMs. Order a subscription and receive
updates 2-4 times a year at significant savings.
CD-ROM Title
System/390 Redbooks Collection
Networking and Systems Management Redbooks Collection
Transaction Processing and Data Management Redbook
AS/400 Redbooks Collection
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RISC System/6000 Redbooks Collection (PostScript)
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J.3 Other Publications
These publications are also relevant as further information sources:
Manuals written for the X.25 LPP:
•
AIXLink/X.25 1.1 for AIX: Guide and Reference , SC23-2520-02.
Other manuals:
 Copyright IBM Corp. 1996
299
•
X.25 Interface Co-Processor/2 Technical Reference , S16F-1879-00.
•
Realtime Interface Co-Processor Portmaster Adapter/A , S33F-5337-01 and
supplements SC28-9598-00 and SC28-9599-00.
•
AIX Communication Concepts and Procedures for RISC ,
GC23-2203-01.
•
AIX Version 3.2 Technical Reference Volume 3:
Communications , SC23-2384-02.
•
AIX Version 3.2 System Management Guide: Communications &
Networks , GC23-2487-00.
•
AIX Version 4 System Management Guide: Communications & Networks ,
SC23-2526-03.
•
The X.25 DTE/DCE and DTE/DTE Interface, SC30-3409-02.
•
AIX SNA Server/6000: Transaction Program Reference , SC31-7003-01.
•
AIX SNA Server/6000: Configuration Reference , SC31-7014-01.
•
AIX SNA Server/6000: Command Reference , SC31-7100-00.
•
AIX V4 Software Problem Debugging and Reporting , GG24-2513-00.
•
Special Thanks to /AIXTRA: IBM′s Magazine for AIX Professionals for
permission to reprint the article entitled ″Networking with X.25″, by Cindy
Kueck Young and Alan E. Hodel, ″Networking with X.25″, January 1992 issue,
G362-1002-00.
J.3.1 Articles
J.4 Non-IBM References
•
ISO 8208 - the International Standard on Information Processing Systems Data Communications - X.25 Packet Level Protocol for Data Terminal
Equipment (1987).
•
ISO 7776 - the International Standard on Information Processing Systems Data Communications - High-Level Data Link Control Procedures Description of the X.25 LAPB-compatible DTE Data Link Procedures .
•
Yellow Book, Volume VIII - Fascicle VIII.2, Data Communication Networks
Services and Facilities, Terminal Equipment and Interfaces, Recommendations
X.1-X.29 (7th Plenary Assembly, Geneva 10-21 November 1980).
CCITT Recommendation X.25, Interface Between Data Terminal Equipment
(DTE) and Data Circuit Terminating Equipment (DCE) for Terminals Operating
in the Packet Mode and Connected to Public Data Networks by Dedicated
Circuit .
•
Red Book, Volume VIII - Fascicle VIII.3, Data Communication Networks
Interfaces, Recommendations X.20-X.32 (8th Plenary Assembly,
Malaga-Torremolinos 8-19 October 1984).
CCITT Recommendation X.25, Interface Between Data Terminal Equipment
(DTE) Data and Circuit Terminating Equipment (DCE) for Terminals Operating
in the Packet Mode and Connected to Public Data Networks by Dedicated
Circuit .
300
RS/0000 X.25 Cookbook
•
Blue Book, Volume VIII - Fascicle VIII.2, Data Communication Networks:
Services and facilities, Interfaces, Recommendations X.1-X.32 (9th Plenary
Assembly, Melbourne 14-25 November 1988, ISBN 92-61-03671-6).
CCITT Recommendation X.25, Interface Between Data Terminal Equipment
(DTE) and Data Circuit Terminating Equipment (DCE) for Terminals Operating
in the Packet Mode and Connected to Public Data Networks by Dedicated
Circuit .
•
Deasington, Richard X.25 Explained: Protocols for Packet Switching
Networks . 2nd edition. Chichester: Ellis Horwood, 1988.
•
Inside X.25: A Manager ′ s Guide , by Sherman K. Schlar, McGraw Hill,
ISBN-0-07-607007-7, 300 pages, 1990.
Appendix J. Related Publications
301
302
RS/0000 X.25 Cookbook
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Abbreviations
EMEA
Europe, Middle East and
Africa
ABBREVIATION
MEANING
ESC
the escape character
AIX
advanced interactive
executive (IBM′s flavor of
UNIX)
FTP
file transfer protocol
GDLC
Generic data link control
(SNA)
GOSIP
government OSI profile (USA)
HCON
HCON - IBM AIX 3270 host
connection program/6000
(licensed program)
AIX BOS
AIX base operating system
APAR
authorized program analysis
report
API
application program interface
ARTIC
a real time interface
coprocessor
HDLC
high-level data link control
(X.25 protocol)
ASCII
American National Standard
Code for Information
Interchange
IP
internet protocol (ISO)
IPC
inter-programm
communication
BCD
binary coded decimal
IPL
initial program load
BSC
binary synchronous
communication
ISO
International Organization for
Standardization
BSD
Berkeley software distribution
(UC at Berkeley, UNIX)
ITSC
International Technical
Support Center
CCITT
Comite Consultatif
International Telegraphique
et Telephonique
Kbps
kilobits per second
LAN
local area network
LAPB
link access protocol balanced
LAPX
link access procedure
balanced (XI)
LLC
logical link control (LAN, top
sublayer of layer 2, IEEE
802.2)
LPP
licensed program product
LU
logical unit
MPQP
IBM 4-Port Multiprotocol
Communications Controller
MTU
maximum transmission unit
(Internet protocols)
Mbps
megabits per second
NIA
network interface adapter
NIS
network information system
(Sun Microsystems Inc.)
CD
carrier detect (RS-232)
COMIO
Common Input/Output
CPU
central processing unit
CTS
clear to send (RS-232)
CU
call up (UNIX / AIX utility for
using modems and
asynchronous lines)
CUD
call/clear user data (XI)
CUG
closed user group (OSI layer
3)
Ctrl
control
DCD
data carrier detect
DCE
data circuit-terminating
equipment (ISO, CCITT, EIA)
DDN
defense data network
DLPI
Data Link Provider Interface
DSE
data switching equipment
NPI
network provider interface
DSR
data set ready
NTN
DTE
data terminal equipment
national trends network (EPA,
USA)
DTR
data terminal ready
NTU
network
terminating/terminator unit
EBCDIC
extended binary coded
decimal interchange code
NUA
network user address
NUI
network user identifier (PPSN)
 Copyright IBM Corp. 1996
307
ODM
object data manager (AIX)
TELNET
U.S. Dept. of Defense′ s
virtual terminal protocol,
based on TCP/IP
OSI
open systems interconnection
PAD
packet assembler /
disassembler (X.25)
TTY
teletypewriter
PING
packet internet groper
TXCLK
transmit clock
PMR
problem management report
TXD
transmit data
PN
part number
UA
unnumbered
acknowledgement
PS/2
IBM Personal System 2
PSDN
packet switching data
network
UUCP
UNIX-to-UNIX communication
protocol
PTF
program temporary fix
V.24
list of definitions for
interchange circuits between
terminal equipment and
circuit-terminating equipment
(CCITT)
PTT
Post Telegraph Telephone
(National Post and
Telecommunication Authority)
PU
physical unit (SNA)
V.35
standards for data
transmission at 48 kilobits per
second (CCITT)
PVC
permanent virtual circuit
QLLC
qualified logical link control
VC
virtual circuit (XI)
RCM
realtime control microcode
VTAM
RISC
reduced instruction set
computer/cycles
virtual telecommunications
access method (IBM) (runs
under MVS, VM, DOS/VSE)
RJE
remote job entry
WAN
wide area network
RPOA
recognized private operating
agency (CCITT)
X.21
ISO standard for interface to
digital transmission services
RTS
request to send (RS-232)
X.25
RXCLK
receive clock
ISO standard for interface to
packet switched
communications services
RXD
receive data
X.28
SABM
set asynchronous balance
mode
SDLC
synchronous data link control
(teleprocessing)
a CCITT recommendation for
the DTE / DCE interface for a
start-stop DTE accessing the
packet assembly/disassembly
facility in a public network
situated in the same country
SMIT
system management
interface tool (AIX)
X.29
SNA
systems network architecture
(IBM)
SNMP
simple network management
protocol
a CCITT recommendation for
procedures for the exchange
of control information
between a packet
assembly/disassembly facility
(PAD), a packet mode DTE or
another PAD
SRC
system resource controller
X.3
SSCPID
system services control point
identifcation
SVC
switched virtual circuit
a CCITT recommendation for
the packet
assembly/disassembly facility
in a public data network
TCP/IP
transmission control protocol
internet protocol
XID
exchange station
identification (SDLC)
bps
bits per second
ms
millisecond
308
RS/0000 X.25 Cookbook
Index
COMIO Emulation 35
Configuring SNMP 147
Consultative Committee on International Telegraph
and Telephone (CCITT) 1
Control Point Profile, changing 163
CUD 84, 146
Special Characters
/etc/hosts
139
Numerics
6-Port V.35 Interface Board/A 26, 29
6-Port X.21 Interface Board/A 26, 29
8-Port RS-232-D/CCITT V.24 Interface Board/A
A
B
279
E
EGYPT 295
End-to-End Transmit Delay Facility
ESCDELAY variable 194
Expedited Data Negotiation 286
C
Call redirection notification 19, 283
Call User Data 84
Called Address Extension 285
Called Line Address Modified Notification
Calling Address Extension 284
CANADA 295
CCITT 1
CCITT Clear and Reset Causes 269
CCITT Diagnostic Codes 269
CCITT Recommendation X.25 5
CCITT Specified Facilities to OSI 284
Changing TCP/IP CUD Values 146
Charging Information Request 280
Charging requesting service 19
chdev command 70, 71
CHILE 295
CHINA 295
Clearing an X.25/IP session 143
Clearing codes 100
closed user group (CUG) 18
Closed User Group Selection 278
Closed User Group with Outgoing Access
Co-Processor/2 25
 Copyright IBM Corp. 1996
D
Data Circuit-terminating Equipment (DCE) 5
Data Link Control (DLC) 159
Data Link Control (DLC) profile, defining 164
Data-Switching Equipment (DSE) 5
Data-Terminal Equipment (DTE) 5
DCE 5
DDN 142
Debugging Information 206
DENMARK 295
Differences between X.25 LPP and AIX V3 bos X.25
support 239
DLC 159
DLPI 35
DSE 5
DTE 5
abbreviations 307
acronyms 307
AIX SNA Server/6000 149
ARGENTINA 295
arpt_killc 143
ARTIC960 Adapter 30
AUSTRALIA 295
AUSTRIA 295
backupx25 89
BELGIUM 295
bibliography 299
Bilateral Closed User Group Selection
BRAZIL 295
26, 29
282
279
286
F
Facilities, list of 276
fast select mode 69
fast select option 19
FC 1170 29
FC 1210 29
FC 1211 29
FC 2028 29
FC 5306 29
FC 6590 29
FC 7006 26
FC 7008 26
FC 7042 26
FC 7046 26
FC 7048 26
FINLAND 295
flow-control parameters negotiation
Fragmentation 222
FRANCE 295
Function Keys not Working Properly
18
194
309
G
M
GERMANY 295
GREECE 295
MALAYSIA 295
manage unexpected results by ping
Maximum facility field length 71
Maximum Transmission Unit 222
mbuf 224
Memory buffers 224
MEXICO 295
Minimum Throughput Class 285
modem setting verification 52
MTU 222
H
Hardware Requirements 39
high-level data-link control (HDLC)
HONG KONG 295
hooks 203
8
I
I (information) frames 8
IBM ARTIC Multiport Adapter Model II 29
IBM ARTIC Portmaster Adapter/A 26
IBM ARTIC960 Adapter 30
IBM X.25 Interface Co-Processor 25
ICELAND 295
implied route 191
INDONESIA 295
Initial Node Setup 161
International Organization for Standardization
(ISO) 3
Interrupt Level 26
IP sessions on the same virtual channel 143
iptrace 223
IRELAND 295
ISO 3
ISO 8208 Diagnostic Codes 271
ISRAEL 295
ITALY 295
J
JAPAN
295
K
KOREA
295
L
link level 8
Link Station profile, defining 165
logical channel 14
Logical Channel States 274
lsdev command 45
lslpp command 52
LU 0 151
LU 1 151
LU 2 151
LU 2 Session profile, defining 169
LU 3 151
LU 3 Session profile, defining 171
LU 6.2 151
LUXEMBOURG 295
310
RS/0000 X.25 Cookbook
192
N
NETHERLANDS 295
network user address (NUA) 12
Network user identification 19, 280
NEW ZEALAND 295
NORWAY 295
NPI 35
O
Open Systems Interconnection (OSI)
OSI 4
4
P
Packet Assembler Disassembler (PAD) 91
packet layer 9
packet level protocol 9
packet-switched data network (PSDN) 1
PAD commands 97
PAD parameters 95, 287
PAD Parameters and Commands 287
PAD parameters, detailed description 289
PAD Profiles, parameter settings for predefined
profiles 101, 102
PAD start 113
PAD stop 113
PAD Support 35
PAD, basic functions of 92
PAD, commands entered from the prompt 290
PAD, messages from PAD to the terminal 292
Performances 219
permanent virtual circuit (PVC) 15
physical connections to the network 47
ping 192
Portmaster Adapter 26, 29
PORTUGAL 295
Problem Determination 181
Product-Specific Diagnostic Codes 271
Profiles for LU 2, defining 163
PSDN 1
PVC 15
Q
W
QLLC 150
Qualified Logical Link Control (QLLC)
150
R
RCM 26
Realtime Control Microcode (RCM) 26
reject packet 184
removex25 89
restart packet 184
restorex25 89
reverse charging 70
Reverse Charging and Fast Select 279
reverse charging option 19
RPOA selection 19, 282
S
S (supervisory ) frames 8
SINGAPORE 295
SMIT screens 227
SNA APIs 152
SNA Diagnostic Codes 271
SNA profiles 153
SNA Server Problem Determination 194
SNA Server/6000 setup for X.25 158
SNMP 35
SOUTH AFRICA 295
SPAIN 295
start IP/X.25 interface 138
static route 191
SVC 15
SWEDEN 295
switched virtual circuit (SVC) 15
SWITZERLAND 295
Window Size Selection 277
Wrap plug 25
Wrap plug Portmaster and Multiport
Wrap plug Co-Processor 255
262
X
X.21 Connection 47
X.21 Pin Assignment 249
X.21bis Connections: V.24 and V.35 47
X.25 Commands 34
X.25 Device Driver 33
X.25 Optional facilities profile, defining 168
X.25 ports 33
X.28 93
X.28 Facility codes 99
X.29 93
X.3 93
X.32 36
x29d 113
xroute 83
xspad command 114
xtalk 74
XTALK Diagnostic Codes 274
Y
YUGOSLAVIA
295
T
Throughput Class 278
throughput class negotiation
TURKEY 295
17
U
U (unnumbered) frames
UNITED KINGDOM 295
USA 295
8
V
V.24/X.21bis Pin Assignment
V.35/X.21bis Pin Assignment
V.36 Pin Assignment 253
virtual circuit 13, 14
VTAM definitions 160
251
252
Index
311
IBML

Printed in U.S.A.
SG24-4475-01
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