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This chapter introduces Eiconcard Connections for Linux. It provides an overview of the Eiconcard Connections for Linux architecture and describes the communications options it offers. It also provides a brief description of Eicon Networks' hardware solution--the Eiconcard--and its supported communications protocols.
Eiconcard Connections for Linux allows you to:
 | Connect a Linux server to local or remote systems over OSI-compliant connections such as X.25, and supports a wide range of OSI communications services. These services include management of communications links to local or remote systems, Packet Assembler/Disassembler (PAD) support (X.3, X.28, and X.29), protocol processing for X.25, HDLC (High-level Data Link Control), Frame Relay, and PPP (Point-to-Point). |
| Eiconcard Connections for Linux also provides complete X.25 application development support through the Eicon X.25 Development Tools. | |
| Link Linux application servers, with their associated TCP/IP LANs, over a wide-area network. Eiconcard Connections for Linux integrates with the TCP/IP stack on your server, using the Eiconcard to route IP traffic over X.25, Frame Relay, PPP, or MultiLink PPP connections to remote TCP/IP hosts and networks. |
| Eiconcard Connections for Linux performs the processing required to pass IP datagrams over WAN protocols, allowing a Linux server to connect with remote networks. |
The Eiconcard Connections for Linux solution is composed of two components:
| The Eiconcard |
| An intelligent communications adapter used in all of Eicon Networks' WAN connectivity solutions. | |
| The Eiconcard Connections for Linux software |
| Provides the protocol software, the Eiconcard driver, and the management utilities required to set up your connections. |
Eicon Networks' Eiconcard is the hardware component of the Eiconcard Connections for Linux solution. One or more Eiconcards can be installed in a Linux server. Each Eiconcard has its own onboard CPU and memory, allowing it to run one or more communications stacks, including X.25, Frame-Relay, Point-to-Point (PPP) and MultiLink PPP. A range of Eiconcards is available for different communications needs, such as high-speed leased line connections, dial-up connections, or ISDN.
As the Eiconcard assumes all network-level protocol processing, the host Linux server's CPU can focus on application processing.
For a list of supported Eiconcards, consult the Eiconcard Connections for Linux Release Notes.
The Eiconcard Connections for Linux software includes three packages:
| Eiconcard Services Package |
| Provides the protocol software (X.25, HDLC, Frame Relay), the Eiconcard driver, and management utilities for the Eiconcard. The Eiconcard Services package is a key component of Eiconcard Connections for Linux and must always be installed first. | |
| Eiconcard Connections for Linux Package |
| Provides the drivers (where applicable) and management utilities required for the following: |
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Eicon Host PAD | |
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Eicon Terminal PAD | |
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Eicon X.25 Application Support | |
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Eicon Routing Services |
| Eicon X.25 Development Tools Package |
| Provides the functionality to develop applications that can use the communication services of the X.25 protocol loaded on the Eiconcard. |
The following diagram shows how the Eiconcard Connections for Linux module integrates into the Linux system.
The above figure shows the user applications that are on the Eiconcard Connections for Linux server.
The PAD Driver architecture consists of the Host PAD and Terminal PAD drivers running on top of the Eiconcard driver. These drivers fully emulate tty drivers, so any asynchronous application written to tty driver standards can function with the Linux PAD drivers.
The Eiconcard Connections for Linux package provides you with four subpackages:
| Eicon Host PAD and Terminal PAD Driver and Utilities |
| Eicon X.25 Application Support |
| Eicon Routing Services Drivers and Utilities |
| Eicon SNMP Services |
The Eicon Host PAD driver allows remote users to access your Linux server over X.25 connections. Host PAD provides this functionality by implementing the X.3, X.28, and X.29 PAD standards. It therefore allows remote login by users on systems conforming to these PAD standards over X.25. Host PAD provides the following capabilities:
| Each Eiconcard port can support multiple Host PAD sessions. |
| The Eiconcard connects directly to the X.25 network, eliminating the need for asynchronous modems and an external PAD. |
| Remote login capability over highly-reliable X.25 communications links. |
The Eicon Host PAD driver is a pseudo-driver linked into the Linux kernel. It uses the services of the Eiconcard driver to access the X.25 protocol running on the Eiconcard. A Linux login daemon such as getty provides incoming connections from Host PAD with a login shell as if the connection were on a local terminal. The Eicon Host PAD driver also provides Host PAD device-configuration utilities and files, and includes a driver-configuration utility (Eicon Host PAD Driver Configuration option in eiconcfg).
Note: The Host PAD Driver only receives calls from remote PAD users, it does not initiate them. The Terminal PAD driver initiates calls to remote hosts over an X.25 network.
The Eicon Terminal PAD driver enables Linux server users to login to remote systems over X.25. Each Eiconcard port supports multiple TPAD sessions. As with the Host PAD, the Terminal PAD provides this functionality by implementing the X.3, X.28, and X.29 PAD standards. It therefore allows local users to login to any remote systems that conform to these PAD standards over X.25.
The Eicon Terminal PAD driver is a pseudo-driver linked into the Linux kernel. It uses the services of the Eiconcard driver to access the X.25 protocol running on the Eiconcard. Linux utilities such as cu and uucp run over the Terminal PAD driver to provide the local user with terminal functionality. The Eicon Terminal PAD driver also provides Terminal PAD device-configuration utilities and files, and includes a driver-configuration utility (Eicon Terminal PAD Driver Configuration option in eiconcfg).
Note: The Terminal PAD driver only initiates calls from local session users, it does not receive them. Use the Host PAD driver to receive calls coming in over an X.25 network.
The diagram below illustrates how the Terminal PAD driver and Host PAD drivers are used in a typical installation.
The Eicon X.25 Application Support subpackage provides the functionality for running applications, developed using the Eiconcard X.25 Development Tools, over an X.25 network. For more information, consult the documentation included with the Eiconcard X.25 Development Tools.
Eicon Routing Services allows you to link Linux servers (Web, application, mail, etc.), with their associated TCP/IP LANs, over a wide-area network. Routing Services integrates with the TCP/IP stack on your Linux server, using the Eiconcard to route IP traffic over X.25, Frame-Relay, Point-to-Point (PPP), or MultiLink PPP connections to remote TCP/IP hosts and networks.
Routing Services performs the processing required to pass IP datagrams over WAN protocols, allowing a Linux server to connect with other networks over a wide area.
The Eicon X.25 Development Tools allows programmers to write user applications that can communicate over the X.25 protocol which resides on the Eiconcard.
The X.25 Development Tools provide a high-level interface that consists of a set of C functions used to perform X.25 network-level requests. This allows you to write your own custom applications which use the full facilities of the Eiconcard and the applicable protocol software.
The X.25 Development Tools are intended for programmers with a basic knowledge of X.25 communications protocols, a good knowledge of C, and familiarity with the applicable operating system.
This same API is available on Windows 2000 and Windows NT, which makes the applications portable.
OSI (Open Systems Interconnection) is a seven-layer hierarchical model for exchanging data. OSI was developed by the International Organization for Standardization (ISO), with the goal of defining, specifying, and relating communications protocols. OSI is a means of standardizing communications between different computer systems.
Eiconcard Connections for Linux supports X.25, HDLC, and Frame Relay protocols.
Eiconcard Connections for Linux is implemented according to the OSI model. The top layer--the Application Layer--is implemented by the PAD Support components or applications developed using the Eiconcard Development Tools. The Network Layer and Data Link Layer are implemented respectively by the X.25 and HDLC protocol support provided by the Eiconcard Services package. The bottom OSI layer--the Physical Layer--is implemented by a media connector on the Eiconcard.
The diagram below shows how Eiconcard Connections for Linux corresponds to the OSI network model.
The Eiconcard Connections for Linux Release Notes provides step-by-step instructions for installing the Eiconcard Connections for Linux product.
The remainder of this user's guide provides information on configuring and operating Eiconcard Connections for Linux.
In addition to this user's guide, the Eiconcard Connections for Linux software includes HTML help pages that provide detailed information on the following:
| Eiconcard Services commands |
| Eicon Host PAD commands |
| Eicon Terminal PAD commands |
| Eicon Routing Services commands |
| Configuring the mpr.if file |
| Eicon X.25 Development environment |
| Eiconcard Connections for Linux troubleshooting |
| Glossary of terms and list of acronyms |
The pages are located in the usr/lib/eicon/docs directory and can be viewed using a Web browser.
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Copyright (c) 2001 Eicon Networks