3COM Dual 56K User Manual

Dual 56K LAN Modem

User Guide

MODEL NO. 3C888

Part No. 1.018.1752 Published May 2000

http://www.3com.com/

3Com Corporation 5400 Bayfront Plaza Santa Clara, California 95052-8145

Copyright © 3Com Corporation, 2000. All rights reserved. No part of this documentation may be reproduced in any form or by any means or used to make any derivative work (such as translation, transformation, or adaptation) without permission from 3Com Corporation.

3Com Corporation reserves the right to revise this documentation and to make changes in content from time to time without obligation on the part of 3Com Corporation to provide notiﬁcation of such revision or change.

3Com Corporation provides this documentation without warranty of any kind, either implied or expressed, including, but not limited to, the implied warranties of merchantability and ﬁtness for a particular purpose. 3Com may make improvements or changes in the product(s) and/or the program(s) described in this documentation at any time.

UNITED STATES GOVERNMENT LEGENDS:

If you are a United States government agency, then this documentation and the software described herein are provided to you subject to the following restricted rights:

For units of the Department of Defense:

Restricted Rights Legend: Use, duplication, or disclosure by the Government is subject to restrictions as set

forth in subparagraph (c) (1) (ii) for Restricted Rights in Technical Data and Computer Software Clause at 48 C.F.R. 52.227-7013. 3Com Corporation, 5400 Bayfront Plaza, Santa Clara, California 95052-8145.

For civilian agencies:

Restricted Rights Legend: Use, reproduction, or disclosure is subject to restrictions set forth in subparagraph

(a) through (d) of the Commercial Computer Software - Restricted Rights Clause at 48 C.F.R. 52.227-19 and the limitations set forth in 3Com Corporation’s standard commercial agreement for the software. Unpublished rights reserved under the copyright laws of the United States.

Unless otherwise indicated, 3Com registered trademarks are registered in the United States and may or may not be registered in other countries.

3Com, OfﬁceConnect, and U.S. Robotics are registered trademarks of 3Com Corporation. 3ComFacts is a service mark of 3Com.

Acrobat and Adobe are registered trademarks of Adobe Systems, Incorporated. America Online is a registered trademark of America Online, Inc. Macintosh is a registered trademark of Apple Computer. Compuserve is a registered trademark of Compuserve Interactive Services, Inc. LZS is a registered trademarks of hi/fn, Inc. Pentium is a registered trademark of Intel Corporation. IBM is a trademark of International Business Machines Corporation. Windows and Windows NT are registered trademarks of Microsoft Corporation. Netscape Navigator is a registered trademark of Netscape Communications. IPX is a registered trademark of Novell, Inc. UL is a trademark of Underwriters Laboratory, Inc.

Other brand and product names may be registered trademarks or trademarks of their respective holders.

Guide written by Eric Heller.

Important Safety Information

MPORTANT

WARNING: Warnings contain directions that you must follow for your personal safety. Follow all

instructions carefully.

Please read the following information carefully and thoroughly before installing the unit:

Take exceptional care during the installation and removal of the unit.

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Locate the unit close to the mains socket outlet, and ensure that the mains socket is accessible.

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Use the power adapter supplied with the unit to ensure compliance with national and

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international safety standards. If there is no power adapter supplied, the mains cordset used must be compliant with the local and national regulations of the target country and must not violate the safety approval of the product (refer to the Approvals section at the back of this manual).

Disconnect the power adapter before moving the unit. Power can only be disconnected from the

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unit by removing the power adapter from the unit or from the socket outlet. Only connect apparatus complying with the relevant interface requirements to the ports on this

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unit. The safety status of the ports on this equipment are as follows.

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Ports identiﬁed by the labels LAN and Phone = SELV. SELV (Safety Extra Low Voltage) is a secondary circuit which is designed and protected so that under normal and single-fault conditions, the voltage between any two accessible parts does not exceed a safe value (42.2 V peak or 60 V DC).

There are no user-replaceable fuses or user-serviceable parts inside the unit. If there is a physical

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problem with the unit that cannot be solved with problem solving actions in this guide, contact the 3Com reseller from whom the equipment was purchased.

If the units are stackable, only stack similar units.

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AFETY

NFORMATION

Wichtige Sicherheits-Informatio nen

WARNING: Twisted Pair RJ45 data ports. These are shielded RJ45 data sockets. They cannot be

used as telephone sockets. Only connect RJ45 data connectors to these ports.

WARNUNG: Warnungen enthalten Anweisungen, die Sie zu Ihrer persönlichen Sicherheit befolgen

müssen. Bitte halten Sie sich daran.

Bitte lesen Sie die folgenden Informationen aufmerksam, ehe Sie die Einheit installieren:

Lassen Sie bei Installation und Abbau besondere Vorsicht walten.

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Stellen Sie die Einheit in der Nähe einer Stromquelle auf und achten Sie darauf, daß diese

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zugänglich ist. Verwenden Sie immer den mitgelieferten Netzadapter, damit die Einhaltung nationaler und

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internationaler Sicherheitsnormen gewährleistet ist. Wurde kein Adapter mitgeliefert, muß das verwendete Netzkabel den lokalen und nationalen Bestimmungen des Landes entsprechen und darf die Sicherheitsbestimmungen des Produkts (siehe den entsprechenden Abschnitt am Ende dieses Handbuchs) nicht verletzen.

Trennen Sie den Netzadapter von der Stromversorgung, bevor Sie die Einheit bewegen. Die

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Einheit kann nur von der Stromversorgung getrennt werden, indem Sie die Verbindung des Netzadapters entweder von Einheit oder der Stromquelle trennen.

Schließen Sie nur Geräte an den Schnittstellen dieser Einheit an, die den

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Interface-Voraussetzungen entsprechen. Die Sicherheitsmerkmale der Schnittstellen dieses Geräts sind:

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Schnittstellen mit der Bezeichnung LAN und Phone = SELV. SELV (Safety Extra Low Voltage) ist ein sekundärer Schaltkreis, der unter normalen und Single-Fault-Bedingungen so eingerichtet

ist, daß die Spannung zwischen zwei zugänglichen Bauteilen einen Sicherheitswert nicht übersteigt (42,2 V Spitzenspannung bzw. 60 V Gleichspannung).

Die Einheit enthält keine Sicherungen oder sonstige Bauteile, die vom Benutzer ausgewechselt

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oder gewartet werden können. Sollte ein physikalischer Fehler auftreten, der mit den in diesem Handbuch beschriebenen Maßnahmen nicht zu beheben ist, setzen Sie sich mit dem 3Com-Vertreter in Verbindung, bei dem Sie das Gerät erworben haben.

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Bei stapelfähiger Konstruktion nur gleichartige Einheiten verwenden.

WARNUNG: Twisted Pair RJ45-Datenschnittstellen. Dies sind abgeschirmte RJ45-Schnittstellen,

die nicht für Telefonsignale verwendet werden können. Schließen Sie an diesen Schnittstellen nur RJ45-Datenstecker an.

Important Notice de Securite

AVERTISSEMENT: les avertissements présentent des instructions que vous devez suivre très

attentivement pour votre sécurité personnelle.

Veuillez lire les informations suivantes attentivement avant l'installation de l'appareil.

Soyez très prudents pendant toute la durée de l'installation et du déplacement de l'appareil.

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Placez l'appareil près d'une prise murale qui doit rester accessible à tout instant.

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Utilisez l'adaptateur électrique fourni avec l'appareil pour garantir la conformité totale aux normes de sécurité nationales et internationales. Si aucun adaptateur n'est fourni, le câble électrique utilisé doit être conforme aux normes locales et nationales du pays et ne doit en aucun cas contrevenir aux normes de sécurité d'utilisation de l'appareil (veuillez consulter la section Approvals (Agréments) au dos du présent manuel).

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Déconnectez l'adaptateur électrique avant de déplacer l'appareil. L'alimentation ne peut être déconnectée de l'appareil qu'en retirant l'adaptateur de l'appareil ou de la prise de courant.

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Ne connectez l'appareil qu'en conformité avec les exigences techniques des ports de connexion de l'appareil. Les normes de sécurité de chaque port sont les suivantes :

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Les ports identiﬁés par les étiquettes LAN et Phone = SELV. Les circuits SELV (Safety Extra Low Voltage, très basse tension de sécurité) sont des circuits secondaires qui sont conçus et protégés pour qu'en conditions normales et à défaillance unique, la tension n'excède jamais la valeur de sécurité de 42,2 V en crête, ou 60 V DC.

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L'appareil ne contient aucun fusible remplaçable par l'utilisateur ni aucune pièce dont la maintenance peut être effectuée par l'utilisateur. Si un problème physique survient dans l'appareil, qui ne peut être résolu au moyen des techniques de dépannage du présent manuel, contactez le revendeur 3Com qui vous a fourni l'appareil.

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Si vous disposez de plusieurs appareils empilables sur racks, n'empilez que les appareils similaires.

AVERTISSEMENT: ports de données RJ45 à paires torsadées. Il s'agit de prises de données RJ45

blindées. Elles ne peuvent être utilisées comme prises de téléphone. Elles ne doivent recevoir que les connecteurs de données RJ45.

Medidas de Seguridad Importantes

ADVERTENCIA: las advertencias contienen instrucciones que es preciso seguir al pie de la letra para

evitar daños personales.

Antes de instalar la unidad, lea atentamente la siguiente información.

Tome todas las precauciones necesarias a la hora de instalar o desinstalar la unidad.

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Coloque la unidad cerca de una toma de corriente de fácil acceso.

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Utilice el adaptador de corriente suministrado con la unidad, de este modo se asegura el pleno cumplimiento de las normas de seguridad nacionales e internacionales. En caso de no recibir un adaptador con la unidad, deberá utilizar un cable que responda a los requisitos estipulados por la normativa local o nacional pertinente y que no contravenga la garantía de seguridad del producto (consulte la sección relativa a este punto al final de esta guía).

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Desenchufe el adaptador antes de mover la unidad. La única forma de interrumpir el paso de corriente consiste en desenchufar el adaptador de la unidad o de la toma de corriente.

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No deben conectarse a los puertos de la unidad aparatos que no cumplan los requisitos de la interfaz en uso. Los puertos de la unidad son de los siguientes tipos:

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Puertos con etiqueta LAN o Phone= SELV. SELV (Safety Extra Low Voltage) es un circuito secundario diseñado para que el voltaje entre dos puntos accesibles no exceda límites seguros (42,2 V punta ó 60 V CC) en circunstancias normales o de fallo simple.

La unidad no contiene fusibles ni otros componentes que el usuario pueda cambiar o reparar. De

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producirse problemas cuya resolución no se explique en esta guía, póngase en contacto con el proveedor de 3Com.

Si las unidades que posee son apilables, acople las que sean similares entre sí.

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ADVERTENCIA: puertos de datos de par trenzado RJ45. Son enchufes blindados RJ45 a los que

sólo deben acoplarse conectores de datos RJ45. No pueden utilizarse como enchufes telefónicos.

Informazioni Importanti per la Sicurezza

AVVERTENZA: il testo delle avvertenze riporta importanti istruzioni alle quali occorre attenersi per

motivi di sicurezza. Seguire attentamente tutte le istruzioni.

Prima di installare l'unità, leggere attentamente le informazioni riportate di seguito.

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Procedere con estrema cautela durante l'installazione e la rimozione dell'unità.

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Collocare l'unità vicino a una presa di corrente e verificare che la presa sia accessibile. Per garantire la conformità alle norme di sicurezza nazionali e internazionali, usare l'adattatore di

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corrente fornito con l'unità. Se l'adattatore non è compreso, il cavo alimentatore deve essere conforme alle norme locali e nazionali del paese di destinazione nonché all'omologazione di sicurezza del prodotto (per ulteriori informazioni consultare la sezione relativa alle omologazioni riportata alla ﬁne del manuale).

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Scollegare l'adattatore prima di spostare l'unità. Per scollegare l'unità occorre rimuovere l'adattatore dall'unità stessa o dalla presa di corrente.

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Collegare alle porte dell'unità solamente apparecchi conformi ai requisiti della relativa interfaccia. Le speciﬁche riguardanti la sicurezza delle porte sono le seguenti:

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Porte contrassegnate dalle targhette LAN e Phone = SELV. SELV (Safety Extra Low Voltage) è un circuito secondario ideato e protetto in modo tale che, in condizioni normali e in caso di un unico guasto, la tensione tra due parti accessibili qualsiasi non superi il valore di sicurezza (42,2 V picco o 60 V CC).

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All'interno dell'unità non vi sono fusibili sostituibili dall'utente o parti la cui manutenzione può essere effettuata dall'utente. Se si verifica un problema che non si è in grado di risolvere seguendo le istruzioni per la risoluzione dei problemi riportate nel presente manuale, contattare il rivenditore 3Com presso il quale si è acquistata l'unità.

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Se le unità sono impilabili, impilare solamente unità simili.

AVVERTENZA: porte dati RJ45 per doppino intrecciato. Si tratta di prese dati RJ45 schermate e

non possono essere utilizzate come prese telefoniche. Collegare solamente connettori dati RJ45 a queste porte.

Additional Safety Information

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Only connect apparatus complying with the relevant interface requirements to the ports on this unit.

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Disconnect the power adapter before moving the unit. Retain this user’s guide for later use and pass it on in the event of change of ownership of

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the unit.

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Protect the unit from sudden, transient increases and decreases in electrical power by ﬁtting an in-line surge suppressor or uninterruptible power supply. Products manufactured by us are safe and without risk provided they are installed, used and maintained in good working order in accordance with our instructions and recommendations.

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If any of the following conditions occur, isolate the electricity supply and refer to your 3Com reseller.

If the case or cover is not correctly ﬁtted or if it is damaged.

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If the unit begins to make an odd noise, smell or smoke.

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If the unit shows signs of a distinct change in performance.

Never install telephone wires during a lightning storm, or install telephone connection

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sockets in wet locations, unless the socket is speciﬁcally designed for wet locations. Do not touch uninstalled telephone wires or terminals unless the telephone line has been

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disconnected at the network interface. Always exercise caution when installing or modifying telephone lines.

Do not use a telephone, which is connected to the unit, to report a gas leak in the vicinity of

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the leak. Do not spill food or liquids on the unit. If the unit gets wet, isolate the electrical supply and

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contact your 3Com reseller.

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Do not push any objects into the openings of the unit. Doing so can cause ﬁre or electric shock by shorting out internal components.

Only equipment approved for use by your telecom company can be connected to the

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telephone port.

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Avoid using a telephone, which is connected to the unit (other than a cordless type), during an electrical storm.

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Equipment connected to the telephone port must be located in the same building as the unit.

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Be sure nothing rests on the units system cables and that the cables are not located where they can be stepped on and cause damage to the unit.

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Keep the unit away from radiators and heat sources. Allow 25mm (1inch) around the unit to provide adequate air circulation.

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Install the unit in a clean area that is free from dust or extreme temperatures.

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Allow a clearance gap of at least a 150 mm (6 inches) from the rear panel of the unit, to allow for cable access.

Interconnecting directly, or by way of other apparatus, to ports complying with SELV

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requirements may produce hazardous conditions on the network. Advice should be sought from a competent engineer before such a connection is made.

ABLE

MPORTANT

Wichtige Sicherheits-Informationen 3 Important Notice de Securite 4 Medidas de Seguridad Importantes 4 Informazioni Importanti per la Sicurezza 5 Additional Safety Information 5

BOUT

Introduction 11 How to Use This Guide 11 Conventions 12 Year 2000 Compliance 12

HIS

AFETY

UIDE

ONTENTS

NFORMATION

NTRODUCTION

Introduction 13 Applications 14 Hardware Description 16 Features 18

UAL

56K LAN M

UNCTIONALITY

LAN Side Connectivity: Installing an Ethernet Hub 21 Wan Side: The Two 56K Modems 22 Using the Modem Channels 22 Dial-in Functionality 25 Understanding Multilink PPP and Other Line Usage Options 27 The Virtual FAX Modem (Windows 95, 98, NT, and 2000) 28 Support for Virtual Private Networks (VPNs) 29

EFORE

Package Contents 31 Before You Begin 31 Why Check TCP/IP and IP Address Settings? 32 Checking TCP/IP and IP Address Settings 32 Adding TCP/IP to Your Protocols List 34

ODEM

ESCRIPTION

EGIN

Setting Up Your Computer If You Have a Static IP Address 39

INSTALLING THE DUAL 56K LAN MODEM

Before You Start the Installation 43

CONFIGURING THE DUAL 56K LAN MODEM FOR INTERNET ACCESS

Typical Conﬁguration 47 Changing the LAN Modem IP Address for Static IP Users 52 The LAN Modem Main Conﬁguration Page 53 Connecting an External Hub to the Dual 56K LAN Modem 56

CONFIGURING THE DUAL 56K LAN MODEM FOR PRIVATE NETWORK A

CCESS

Before You Start the Conﬁguration 59 Conﬁguration Steps 60 Changing the LAN Modem IP Address for Static IP Users 67 The LAN Modem Main Conﬁguration Page 68 The LAN Modem Support Web Site 70

ADVANCED CONFIGURATION

Advanced Conﬁguration 71 Conﬁguring Additional Service Providers 71 Editing Service Provider Proﬁles 76 Associating Service Providers with Workstations on the LAN 76 Using a Connection Script 77 Conﬁguring LAN Parameters 81 Conﬁguring V.90 Modem Control Parameters 83 Changing Data Call Parameters 85 Specifying a WINS Server Address 87 Conﬁguring the Local DNS Table 88 Reserving DHCP Addresses 89 Changing Your Password 89 Locking and Unlocking the Conﬁguration 90 Using Selective Password Protection 91 Conﬁguring the LAN Modem from a Remote Location 91 Checking for Dual 56K LAN Modem upgrades 94

CONFIGURING THE DUAL 56K LAN MODEM FOR DIAL-IN SUPPORT

Understanding Dial-in Basics 95 Understanding the Three Dial-in Proﬁle Types 96 Part I. Conﬁguring the Server-side Dual 56K LAN Modem for Dial-in Support 99 Part II. Conﬁguring a Client Device for Dial-out Access 109 Conﬁguring Dial-in User Parameters 114

Placing a Call from a Client-side LAN Modem 118

PLACING, RECEIVING AND DISCONNECTING CALLS

Using the LAN Modem Desktop Manager (Windows only) 119 Placing Calls 119 Receiving Calls 121 Disconnecting Calls 122

TROUBLESHOOTING AND MAINTENANCE

Checking the Basics 125 Monitoring LEDs 125 Evaluating Symptoms and Solutions 126 Finding More Information 131 Contacting Technical Support 131 Downloading Firmware to Your Dual 56K LAN Modem 131 Resetting the Dual 56K LAN Modem 131 Reviewing Statistics 132 Synchronizing the LAN Modem Clock 134

NETWORKING PRIMER

What is a network? 137

INSTALLING AND USING THE VIRTUAL FAX MODEM

Installing the Virtual FAX Modem 147

CREATING A VIRTUAL PRIVATE NETWORK (VPN) TUNNEL

Creating a Virtual Private Network (VPN) Tunnel 151

FACTORY DEFAULTS

Dual 56K LAN Modem Factory Defaults 153

SPECIFICATIONS

Speciﬁcations 155 Year 2000 Compliance 155

GLOSSARY

3COM CORPORATION LIMITED LIFETIME WARRANTY

REGULATORY AND APROVAL INFORMATION

ABOUT THIS GUIDE

About This Guide provides an overview of this User Guide, describes guide conventions, and shows you where to look for speciﬁc information.

Introduction This guide tells you how to install and conﬁgure the Dual 56K LAN Modem and

provides descriptions of key applications and networking concepts.

Audience Description This guide is intended for end users with no presumed level of expertise.

How to Use This Guide

Table 1 shows you where to ﬁnd speciﬁc information in this guide.

Table 1 Speciﬁc Information

If you are looking for... Turn to...

An overview of the Dual 56K LAN Modem Chapter 1 A description of the Dual 56K LAN Modem hardware components Chapter 1 An explanation of the Dual 56K LAN Modem’s key functionality Chapter 2 Instructions on checking TCP/IP and IP address settings Chapter 3 Instructions on installing the Dual 56K LAN Modem Chapter 4 Instructions on configuring the Dual 56K LAN Modem for Internet access Chapter 5 Instructions on configuring the Dual 56K LAN Modem for private network access Chapter 6 Instructions on advanced configuration of the Dual 56K LAN Modem Chapter 7 Instructions on configuring the Dual 56K LAN Modem for dial-in support Chapter 8 Information on placing and disconnecting calls and using the Desktop Manager Chapter 9 Information on troubleshooting and maintenance Chapter 10 Background information on networking Appendix A Information on installing and using the Virtual FAX Modem application Appendix B Information on creating a virtual private network (VPN) tunnel Appendix C Dual 56K LAN Modem factory default settings Appendix D Technical specifications for the Dual 56K LAN Modem Appendix E Glossary definitions for terms used in this guide Glossary

12 ABOUT THIS GUIDE

Conventions Table 2 and Table 3 list conventions that are used throughout this guide.

Table 2 Notice Icons

Icon Notice Type Alerts you to...

Information note Important features or instructions

Caution Risk of personal safety, system damage, or loss of data

Warning Risk of severe personal injury

Table 3 Text Conventions

Convention Description

Commands The word “command” means you must enter the command exactly as

The words “enter” and “type”

[Key] names Key names appear in text in one of two ways:

Menu commands and buttons

Words in italicized type

Words in bold-face type

shown in text and press the Return or Enter key. Example:

To remove the IP address, enter the following command:

SETDefault!0 -IP NETaddr = 0.0.0.0

NOTE: This guide always gives the full form of a command in

uppercase and lowercase letters. However, you can abbreviate commands by entering only the uppercase letters and the appropriate value. Commands are not case-sensitive.

When you see the word “enter” in this guide, you must type something and then press the Return or Enter key. Do not press the Return or Enter key when an instruction simply says “type.”

■ Referred to by their labels, such as “the Return key” or “the Escape

key”

■ Written with brackets, such as [Return] or [Esc].

If you must press two or more keys simultaneously, the key names are linked with a plus sign (+). Example:

Press [Ctrl]+[Alt]+[Del].

Menu commands or button names appear in italics. Example:

From the Help menu, select Contents.

Italics emphasize a point or denote new terms at the place where they are defined in the text.

Bold text denotes key features.

Year 2000 Compliance The OfﬁceConnect LAN Modem is Year 2000 compliant. Speciﬁcally, its system

clock is capable of accepting and storing dates including and beyond the year

2000. For information on Year 2000 compliance and 3Com products, visit the 3Com Year 2000 web page:

http://www.3com.com/products/yr2000.html.

INTRODUCTION

This chapter provides an overview of the OfﬁceConnect® Dual 56K LAN Modem, referred to throughout this document as the Dual 56K LAN Modem, or simply as the LAN Modem.

Introduction The Dual 56K LAN Modem is an easy-to-install, Local Area Network (LAN) to Wide

Area Network (WAN), analog IP router. The LAN Modem provides four 10BASE-T Ethernet ports for LAN-side connections and two internal, V.90 ITU 56K-standard modems for WAN-side connections, plus two additional analog ports for standard analog equipment such as a phone and/or fax machine.

To conﬁgure the Dual 56K LAN Modem, you use a standard web browser on a computer attached to the LAN Modem to access the LAN Modem’s web-based conﬁguration screens. Afterwards, you can attach up to three additional computers directly to the LAN Modem, or a combination of external hubs and computers, to create WAN access for up to 25 users.

Dial-in and Dial-out

Access

Dual 56K Analog

Modems

The Dual 56K LAN Modem supports both dial-in and dial-out remote access. This means that you can use the LAN Modem on either end of a LAN-to-WAN connection: to call out from your local LAN to an already existing network (such as the Internet or a private, corporate network), or to receive calls into your LAN from up to ten previously-deﬁned remote sites. For calls to a private network via the Internet, where security is a consideration, the LAN Modem also supports pass-though VPN (Virtual Private Network) tunneling.

The V.90 56K ITU standard used on each of the Dual 56K’s internal modems provides download speeds of up to 56K can be accessed independently on a ﬁrst-come, ﬁrst-served basis by any combination of users dialing out from the LAN and users dialing in to the LAN for separate, 56K connections. Or, the LAN Modem can be conﬁgured to provide one high-speed connection at a time.

The Dual 56K LAN Modem is software upgradeable, allowing for easy upgrades to new features and enhancements as they become available. Visit the LAN Modem Web site for the latest ﬁrmware releases: http://www.3com.com/support/docs/lanmodem.

1.Capable of receiving downloads at up to 56 Kbps and sending at up to 31.2 Kbps. Due to FCC regulations, receiving speeds are limited to 53 Kbps. Actual speeds may vary. Requires compatible analog phone line and server equipment. The Dual 56K LAN Modem complies with the V.90 ITU standard and is backwards-compatible with all US Robotics 56K standards. Standard ofﬁcially determined in February, 1998; ratiﬁed in September, 1998.

for each analog line. The two modems

14 CHAPTER 1: INTRODUCTION

Applications The primary applications for the Dual 56K LAN Modem are:

■ Local networking with shared, dial-out access to the Internet

■ Local networking with shared, dial-out access to a private network, such as a

remote corporate ofﬁce LAN (this can include indirect Internet access through the private network’s Internet connection)

■ Local networking with shared, simultaneous dial-out access to the Internet and

a private network

■ Combined dial-in and dial-out access for several possible networking scenarios

(refer to Chapter 8 for speciﬁc dial-in applications).

The following diagrams illustrate the primary Dual 56K LAN Modem applications:

Local Networking with Shared Internet Access

Local Networking with

Shared Private Network

Access

Users can share access to the Internet while they continue to network locally, as shown in Figure 1.

OfficeConnect Dual 56K LAN Modem

r A

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

Public telephone

network

Internet

Two analog POTs lines

Figure 1 Local Networking with Shared Internet Access

Users can share access to a remote private network, such as a corporate ofﬁce LAN, while they continue to network locally. This can include indirect access to the Internet through the private network’s Internet connection, as shown in Figure 2.

OfficeConnect Dual 56K LAN Modem

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

Two analog POTS lines

Public telephone

network

Private network

Figure 2 Local Networking with Remote Private Network Access

ted

Internet

 onnec c More

m o C

3 E L

O S N O C

N K C A T S 0 0 5 1 m

e t s y

s e c c A e t

m e R R

E X

P T N U A S K

W L

K C

r e

T w o

X P

s U

N D

t D

S S I I R B 4 3 4 / 3 D 2 / 1 2 T O

2 L 1 S

4 G O L A N A

1 1 T O L S 2

Dedicated or leased line connection

Applications 15

OfficeConnect Dual 56K LAN Modem

Public telephone

network

Two analog POTs lines

Dial-in modem user

Server

Workstation

Internet

private network

OfficeConnect Dual 56k LAN Modem

LAN StatusMODEM 2MODEM 1

Local Networking with

Shared Access to the

Internet and a Private

Network

Users can share simultaneous access to both the Internet and a remote private network while they continue to network locally, as shown in Figure 3.

Internet

OfficeConnect Dual 56K LAN Modem

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

Two analog POTS lines

Figure 3 Local Networking with Shared Access to the Internet and a Remote Private Network

Public telephone

network

ted



ec n n

co e r o M

o C

3 E L O S N O

T E N K C A T

S 0 0 5 1

m e t s y

N S

A s

L s e c c A e t

R m e R R

T N

W L

K C

r e

A T w S

o X P t

R e s e R

u t a

S S I I R B 4 3 4 / 3 D 2 / 1 2 T O

2 L 1 S

4 G O L A N A 3

1 T O L S

Private network

Combined Dial-in and

Dial-out Access

Users can share access to the Internet or a remote private network and continue to network locally, while a user dials in for access to a server or servers on the LAN, as shown in Figure 4. (Other dial-in scenarios are possible. Refer to Chapter 8 for speciﬁc applications.)

Figure 4 Local Networking and Dial-out Access with Dial-in Support

16 CHAPTER 1: INTRODUCTION

Hardware Description The following is an overview of the Dual 56K LAN Modem hardware, including the

function of the front panel LEDs and back panel connectors.

Front Panel LED

Description

The front panel contains the LEDs illustrated in Figure 5.

essage

Alert

Pow

Figure 5 Dual 56K LAN Modem Front Panel

LAN StatusMODEM 2MODEM 1

COLL

OfficeConnect Dual 56k LAN Modem

The functions of the front panel LEDs are described in Table 4. These front panel LEDs indicate proper operation and display analog modem and Ethernet port activity status.

Table 4 Front Panel LED Indicator Deﬁnitions

LED Color Description

Alert Amber Operational Status. Lit during power-on self-diagnostic test

Power Green Power Indicator. Remains lit as long as power is supplied to

Message Not implemented. AA (MODEM 1 or 2) Green Auto Answer. Shows the answer status for Modem 1 or 2,

CD (MODEM 1 or 2) Green Carrier Detect. Remains lit for the indicated modem if the

RD (MODEM 1 or 2) Green Received Data. Flashes when the indicated modem receives

SD (MODEM 1 or 2) Green Send Data. Flashes when the indicated modem sends data to

OH (MODEM 1 or 2) Green Off Hook. Remains lit when the indicated modem has gone

TX Green Ethernet Transmit Status. Flashes green when data is being

or after pressing the reset button. Off indicates that the unit has passed the diagnostic test and

is working properly. Flashes if one or more of the diagnostics have failed or after

the unit is placed in firmware download mode and is awaiting firmware upgrade.

the unit.

as follows:

■ Flashes during an incoming call.

■ Remains lit for the duration of the call.

■ Off when the LAN Modem originates a call.

Dual 56K LAN Modem receives a valid data signal (carrier) from a remote modem (such as an ISP), indicating that data transmission is possible.

data from a remote site.

a remote site.

off hook.

transmitted to the Ethernet LAN from the Dual 56K LAN Modem.

Off indicates that no data is being transmitted to the Ethernet LAN from the Dual 56K LAN Modem.

Hardware Description 17

10-30V DC

2A MAX

RESET

LAN

LINE 1 PHONE 1 LINE 2 PHONE 2

Table 4 Front Panel LED Indicator Deﬁnitions (continued)

LED Color Description

COLL Amber Ethernet Collision Status. Flashes amber when some

collisions are taking place on the Ethernet LAN. Off indicates that no collisions are taking place on the

Ethernet LAN.

Ports 1-4 Green Ethernet LAN Port Status. On indicates that the unit

detects the Ethernet link integrity signal from an attached computer and operation is normal.

Flashes when the LAN Modem receives data on the associated port.

Off indicates that the unit does not detect the Ethernet link integrity signal. The Ethernet cable may not be properly connected or the cable may be the wrong polarity.

Back Panel Connector

Description

The back panel contains the connectors illustrated in Figure 6.

Figure 6 Dual 56K LAN Modem Back Panel

From left to right, the back panel consists of the following:

■ Power: Connect the power module cable to this port.

■ RESET: Press this button to re-initialize or factory re-set the unit (refer to

Chapter 10 for instructions).

■ LAN 1, 2, 3, and 4: Connect up to four computers (or a combination of

computers and an external hub), to these four 10BASE-T Ethernet ports.

■ LINE 1: Connect one of the provided RJ-11 analog cables from the wall outlet

to this port.

■ PHONE 1: Connect an external analog device, such as a telephone or fax

machine, to this port.

■ LINE 2: Connect the second RJ-11 analog cable from the wall outlet to this

port.

■ PHONE 2: Connect an additional external analog device, such as a telephone

or fax machine, to this port.

18 CHAPTER 1: INTRODUCTION

Features Ease of Installation and Use

■ Web-based, point-and-click user interface for easy conﬁguration

■ Automatic Internet conﬁguration veriﬁcation via your Internet Service Provider

(ISP)

■ Web-based, context-sensitive online help

■ Dial-in Wizard for easy conﬁguration of dial-in setup

■ LAN Modem Desktop Manager tool for easy management and stats

monitoring (Windows 95

■ EZ- LAN Wizard, which optimizes workstation settings for use with the Dual

, 98®, NT® and 2000®)

56K LAN Modem (Windows 95, 98, NT and 2000)

High Performance

■ Two internal 56K modems, capable of downloading at speeds of up to 112

■ V.42/MNP 2-4 error control and V.42 bis/MNP 5 data compression

■ Hi/fn™ LZS

Kbps

(without compression)

compression, which conforms to the following IETF RFCs: The PPP

Compression Control Protocol (RFC 1962) and PPP Stacker LZS Compression Protocol (RFC 1974)

Connectivity

■ Two 56K integrated analog modems

■ Built-in four-port 10BASE-T, 10 Mbps Ethernet hub. Up to 25 users can be

supported by adding an external Ethernet hub

■ Two pass-through, analog voice ports for connecting up to two external analog

devices

■ Virtual Private Network (VPN) pass-through capability using client software

Virtual FAX Modem

■ Allows Windows users on the LAN to access one or both modems as if directly

connected through an RS-232 serial (COM) port.

■ Creates support for applications requiring a dedicated modem, such as Class

2.0 fax applications, and online services.

Routing

■ IP Routing

■ Dynamic or static IP addresses supplied by your service provider (WAN side)

■ Dynamic Host Conﬁguration Protocol (DHCP) server functionality on the LAN,

which automatically assigns an IP address to a newly-attached PC on the IP network

■ Domain Name Service (DNS) server functionality for the LAN, which translates

the common, alphanumeric name of a device (for example, “www.3com.com”) to its numeric IP address

1.Current FCC rules limit download speeds to 53Kbps per modem.

Features 19

■ Network Address Translation (NAT) between LAN and WAN, which allows

multiple users on the LAN to share a single remote connection and user account.

■ Intelligent NAT, an enhancement to NAT which enables UDP applications to

work with the Dual 56K LAN Modem.

■ Multiplexing trafﬁc from several computers to remote destinations

Bandwidth Management

■ Automatic call initiation (also known as dial-on-demand routing)

■ Automatic disconnection of idle calls after a speciﬁed length of time

■ Multilink PPP, which combines two PPP calls on two analog lines into a single,

high-speed network connection.

■ Bandwidth on Demand using Bandwidth Allocation Control Protocol

(BACP)/Bandwidth Allocation Protocol (BAP), based on a speciﬁed threshold.

■ Dynamic Bandwidth Allocation (DBA), which allows you to place a voice or

data call while a Multilink PPP call is active.

■ Manual call connection and disconnection

Remote Management

■ Remote management via Web browser-based interface

■ Remote ﬁrmware upgrades

Protocols

■ IETF PPP (RFC 1661, 1662, 1663)

■ IETF Multilink PPP (RFC 1990)

■ IETF Password Authentication Protocol (PAP) and Challenge Handshake

Authentication Protocol (CHAP) security (RFC 1994)

■ MS-CHAP support (as deﬁned in Network Working Group Information Memo:

Microsoft PPP CHAP Extensions. S. Cob, Rev. 1.3 March 1997 including only

the functionality that keeps with IETF 1994).

■ IP address negotiation using IPCP (RFC 1332)

■ Network Address Translation (NAT) between LAN and WAN (RFC 1631)

■ Point-to-Point Tunneling Protocol (PPTP—PPTP draft-ietf-pppext-pptp-02.txt).

■ Microsoft Callback Control Protocol (CBCP)

■ BACP/BAP (RFC 2125)

■ LCP Extension Protocol (for Callback functionality) (RFC 1570)

■ Telnet Com Port Control Option (RFC 2217)

Error Control and Data Compression

■ ITU-T V.42

■ ITU-T V.42bis

■ MNP 2-5

20 CHAPTER 1: INTRODUCTION

Modulation Schemes

■ V.90 (backwards-compatible with all US Robotics 56K Standards)

■ ITU-T V.34+

■ ITU-T V.34

■ ITU-T V.32bis

■ ITU-T V.32

■ ITU-T V.22bis

■ ITU-T V.22

■ ITU-T V.23

■ Bell 212A

■ ITU-T V.21

■ Bell 103

Security

■ PAP, CHAP and MS-CHAP support

■ Callback support for dial-in and dial-out calls

Upgradeability

■ Flash memory for ﬁeld ﬁrmware updates

■ Firmware posted on 3Com’s Web site

■ Fully upgradeable to future 56K standards

Diagnostics

■ LED status display

■ Statistics display

Warranty

■ 3Com Corporation Limited Lifetime Warranty (refer to the end of this User

Guide for details).

Support for Internet Applications

Support for applications that use the User Datagram Protocol (UDP) and the Transmission Control Protocol (TCP). The UDP protocol is used primarily by Internet games.

Look for the latest list of Internet applications and games that are interoperable with the LAN Modem at

http://www.3com.com/support/docs/lanmodem/.

DUAL 56K LAN MODEM

UNCTIONALITY DESCRIPTION

This chapter explains the Dual 56K LAN Modem’s key functionality for users who wish to gain a fuller understanding of the LAN Modem before attempting to install and conﬁgure the unit. The following topics are covered:

■ LAN Side Connectivity: Installing an Ethernet Hub

■ Wan Side: The Two 56K Modems

■ Using the Modem Channels

■ Dial-in Functionality

■ Understanding Multilink PPP and Other Line Usage Options

■ The Virtual FAX Modem (Windows 95, 98, NT, and 2000)

■ Support for Virtual Private Networks (VPNs)

For a basic understanding of modems and networking, refer to the Networking Primer in Appendix A.

LAN Side Connectivity: Installing an Ethernet Hub

On the Local Area Network (LAN) side of the Dual 56K LAN Modem, you can connect up to four computers and/or printers directly to the unit’s built-in Ethernet hub. This allows you to create a LAN and enable ﬁle-, application-, and printer-sharing among the attached devices. By connecting an external hub (not included) to one of the four LAN ports, you can increase the number of users to a total of 25. An example of a ten-workstation connection is shown in Figure 7.

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

r A

OfficeConnect Dual 56K LAN Modem

Port Status

Network Utilization

5678

PWR COLLPKT COAX1234

1%2% 3% 6%12%25%50%80%

Alert

green = link OK, off = link fail, yellow = partition

OfficeConnect Ethernet Hub 8

Figure 7 Dual 56K LAN Modem Ten Workstation Connection Example.

22 CHAPTER 2: DUAL 56K LAN MODEM FUNCTIONALITY DESCRIPTION

Wan Side: The Two 56K Modems

Using the Modem Channels

On the Wide Area Network (WAN) side of the Dual 56K LAN Modem, up to 25 users can share access to the WAN through use of the LAN Modem’s two internal 56K modems. When you conﬁgure the Dual 56K LAN Modem, you can choose one of two ways to use two analog lines:

■ Two separate connections to different locations (one per analog line, or

“channel”)

■ One high-speed connection at a time, using Multilink Point-to-Point Protocol

(Multilink PPP) to combine the two analog channels into one.

For an explanation of Multilink PPP, refer to “Understanding Multilink PPP and Other Line Usage Options” later in this chapter.

Once a WAN connection is established, up to 25 users can share the open connection and access the same location simultaneously.

When you use the Dual 56K LAN Modem for its most common WAN application, dial-out remote access, you can conﬁgure up to four remote destination proﬁles, referred to as Service Providers. For each Service Provider that you conﬁgure, you can choose whether to set up the connection as a single analog “channel” connection, or as a Multilink-enabled connection.

If two or more Service Providers are set up in the LAN Modem, each as a single channel connection, the following typical dial-out scenario becomes possible, as shown in Figure 8.

Greg’s PC

Internet

Greg

Marsha’s PC

r A

OfficeConnect Dual 56K LAN Modem

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

Greg Peter

Two analog lines

Public telephone

network

Pet

 rt Hea e h



o t t rk. ge wo

t d E

Ne e h

the f o om t r F

Peter’s PC

Remote Private

Jan’s PC

Network

Figure 8 Two Simultaneous Dial-out Connections to Two Different Remote Locations

Using the Modem Channels 23

OfficeConnect

Dual 56K LAN Modem

Combining both analog lines with Multilink provides a single high-speed connection

Eric’s PC

Private network

Anne’s PC

Suhlle’s PC

Floyd’s PC



s R

X L

OfficeConnect Dual 56k LAN Modem

LAN StatusMODEM 2MODEM 1

Public telephone

network

If one or more Service Providers are conﬁgured as a Multilink-enabled connection, one high-speed call at a time is possible whenever one of these calls is in session, as shown in Figure 9.

Figure 9 One High-Speed Connection to a Single Location

Sharing an Already

Established Connection

In either of the above scenarios, once the dial-out connection is established, up to 25 users can share the already-open connection. The LAN Modem is designed to make use of already-established call connections in order to provide optimal line availability for all users sharing WAN access.

Whenever the LAN Modem receives an information packet requesting WAN access, it looks for an already-established connection to the speciﬁed destination (such as an ISP for an Internet connection). If an open connection is available, the LAN Modem uses this for any authorized user. The LAN Modem uses the IP address translation system, Network Address Translation (NAT), to allow multiple users to transmit their individual information packets along this same open channel. If you choose, you can restrict line sharing so that only authorized users have access to an open connection to a speciﬁed destination.

Note that speed may be affected when multiple users share a connection and attempt to download data simultaneously.

For a further explanation of NAT and IP address translation in the LAN Modem, see “IP Address Translation Using NAT,” at the end of this section, or refer to the Networking Primer in Appendix A.

Callback Capability When you conﬁgure a Service Provider proﬁle to a remote destination, you can

choose to enable Callback in the LAN Modem. With Callback enabled, your outgoing call is immediately dropped by the receiving device and then returned, provided the call-receiving device is also set up with this feature. Callback can provide potential cost savings for the dial-out party, as well as security for the call-receiving device and its attached network.

24 CHAPTER 2: DUAL 56K LAN MODEM FUNCTIONALITY DESCRIPTION

Dial-out Call Routing When the LAN Modem makes an outgoing call, it follows a speciﬁc order for

routing data packets, based on the destination Network ID (that is, the IP address and subnet mask) associated with the packet. If you plan to conﬁgure more than one Service Provider in the LAN Modem, and in particular if you are conﬁguring both an Internet Service Provider and a Private Network Service Provider that includes Internet access, you may want to understand how routing order is determined in the LAN Modem.

When the LAN Modem receives a packet requesting WAN access, it looks ﬁrst to see whether the Network ID of the packet matches the Network ID of a conﬁgured Private Network. If the Network ID of the packet matches the Network ID of the Private Network, then the call is placed to the Private Network; if it does not match the Network ID of the Private Network, then the call is routed to the ﬁrst conﬁgured ISP connection.

IP Address Translation

Using NAT

When the Dual 56K LAN Modem is conﬁgured for any type of dial-out access, by default the IP address translation system, Network Address Translation (NAT), is used to enable IP address sharing among the attached workstations.

NAT works by taking the local, private (i.e., not “publicly-routable”) IP addresses of individual workstations attached to the LAN and translating them into a single, publicly-routable IP address assigned by the remote location and used speciﬁcally for communication across the WAN. Unlike a publicly-routable IP address, a local IP address cannot be used for communication across the WAN and is functional only within the boundaries of the LAN.

By translating the local IP addresses of each workstation in this way, the LAN Modem can send out all packets destined for the same remote location over an already-established connection. The LAN Modem in effect “masquerades” as a single user in its communication with the remote, call-receiving device.

The following example shows IP address translation as it occurs in the LAN Modem when three users share a single connection to the Internet.

Jack’s PC

192.168.1.2

Chrissy’s PC

192.168.1.3

Larry’s PC

192.168.1.4

192.168.1.2

.168.1.4

192.168.1.5

LAN Modem translates local IP addresses to ISP-assigned IP address

r A

OfficeConnect Dual 56K LAN Modem

192.168.1.1

Internet

.75

ISP-assigned IP address

204.71.201.75

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

Analog POTS line

Public telephone

network

204.71.201

204.71.201.7 20

4.71.201.7

Analog POTS line

Janet’s PC

192.168.1.5

Figure 10 Network Address Translation in a Dial-out Connection to the Internet

Dial-in Functionality 25

Small Office LAN

Server

OfficeConnect

Dual 56K LAN Modem

Two analog lines

Telecommuter

Internet

Public telephone

network

N O

m 3

OfficeConnect Dual 56k LAN Modem

LAN StatusMODEM 2MODEM 1

Dial-in Functionality When you set up the LAN Modem for dial-in support, you can conﬁgure up to ten

designated Dial-in Users to dial in to the local LAN. In addition, you must conﬁgure Dial-in Global Parameters which apply to all dial-in calls.

When you conﬁgure Dial-in Global Parameters, you choose whether to allow one or both channels to be used for dial-in calls. In addition, you choose whether to set up all dial-in connections as single channel calls or Multilinkenabled calls, and you also set the number of rings before the LAN Modem answers the incoming data call. Depending upon your choice, the following typical calling scenarios become possible:

Simultaneous Dial-in

and Dial-out Calls

If you conﬁgure the LAN Modem to make only one channel available for dial-in calls, you can have one dial-in and one dial out call occurring simultaneously, as shown in Figure 11.

Figure 11 Simultaneous Dial-in and Dial-out Connections

26 CHAPTER 2: DUAL 56K LAN MODEM FUNCTIONALITY DESCRIPTION

Simultaneous Dial-in

Calls from Two Different

Locations

High-speed Dial-in Call

from One Location

If you conﬁgure the LAN Modem to make both channels available for dial-in calls, each as a single channel connection, you can have simultaneous dial-in calls from two different locations, as shown in Figure 12.

Small Office LAN

Server

m e d o 2 9

M 8 N C

L N D S I

S U T A T S

A L

1 L L O C X T 2 B 1 B N D S

I E

O P T

R E L A

Telecommuter

Public telephone

network

OfficeConnect Dual 56k LAN Modem

r A

OfficeConnect Dual 56K LAN Modem

Telecommuter

LAN StatusMODEM 2MODEM 1

Busine

ss traveler

Two analog lines

Business traveler

Figure 12 Simultaneous Dial-in Connections from Two Different Remote Locations

If you conﬁgure the LAN Modem to make both channels available as a single, Multilink connection for dial-in calls, then one high-speed dial-in call at a time is possible, as shown in Figure 13.

Line Sharing with Dial-in

Calls

Small Office LAN

Server

LAN StatusMODEM 2MODEM 1

OfficeConnect Dual 56k LAN Modem

Second small

office site

Public telephone

network

OfficeConnect

Combining both analog lines with Multilink provides a single high-speed connection

Dual 56K LAN Modem

Figure 13 One High-Speed Dial-in Connection from a Single Location

With dial-in calls to the LAN Modem, whenever an open channel is created by an incoming call via the LAN Site-to-Site dial-in scenario, the LAN Modem is designed to make use of the already-open connection by returning any data packets to the dial-in user on the open connection. This leaves the second analog channel free for use, provided you have not set the LAN Modem to combine its two lines using Multilink PPP. Without this line sharing feature, a separate, outgoing call would be launched on the second channel during data transfers.

Understanding Multilink PPP and Other Line Usage Options 27

Callback Capability with

Dial-in Calls

Understanding Multilink PPP and Other Line Usage Options

Multilink Point-to-Point

Protocol (MLPPP)

BACP/BAP In conjunction with Multilink PPP, the protocol pair BACP/BAP (Bandwidth

When you conﬁgure the LAN Modem for dial-in support, you can choose to enable Callback in each Dial-User proﬁle that you create. When Callback is enabled, the LAN Modem is designed to identify the authorized Dial-in User, drop the incoming call, and immediately place a return call to that user. This provides security for the network attached to the LAN Modem, as well as potential cost savings for the Dial-in User.

In order for dial-in Callback to work, the calling device at the other end must also be set up with a Callback feature.

When the Dual 56K LAN Modem’s two analog lines are used independently, each uses the PPP (Point-to-Point Protocol), which is commonly used for the establishment of dial-up connections, such as to the Internet. In some conﬁgurations of the Dual 56K LAN Modem, you will encounter the following protocols, used in connection with PPP.

Multilink PPP is a protocol which allows two or more PPP connections to be combined to form a single, high-bandwidth connection or channel. In the case of the Dual 56K LAN Modem’s two 56K lines, Multilink PPP is used to combine these two 56K connections into a virtual, single 112K connection.

Allocation Control Protocol and Bandwidth Allocation Protocol) are used to negotiate the addition and removal of the second modem connection with the receiving device, based on a user-deﬁned threshold. The advantage of BACP/BAP is that it provides a higher probability of establishing a Multilink PPP call by providing a speciﬁc telephone number for the second modem to call during high trafﬁc conditions.

Dynamic Bandwidth

Allocation (DBA)

Multilink PPP

Conﬁguration Options

Dynamic Bandwidth Allocation (DBA) is another protocol used in conjunction with Multilink PPP to maximize efﬁciency of line usage. With Dynamic Bandwidth Allocation enabled, if a Multilink call is in progress, the LAN Modem can automatically and temporarily remove one of the channels from the call and use it to place a data call to another service provider without disturbing the original call. The only effect on the original call is that speed is temporarily reduced from Multilink PPP to one analog channel. Once the second outgoing data call ends, that channel is then returned to the Multilink PPP call, assuming that “Add Second Channel As Required” has been conﬁgured for that service provider. Although throughput is reduced while the second call is active, the reliability of the Multilink PPP call is maintained.

If you enable Multilink PPP when you conﬁgure the Dual 56K LAN Modem, you will be able to choose from among the following Multilink PPP options:

■ Use One Channel

When this option is conﬁgured, only one modem channel is used when connecting to a remote destination. In this case, Multilink PPP is disabled, and neither DBA nor BACP/BAP is used.

■ Use Two Channels

28 CHAPTER 2: DUAL 56K LAN MODEM FUNCTIONALITY DESCRIPTION

When this option is conﬁgured, both modem channels are used every time a connection is made to a remote destination, regardless of the amount of trafﬁc being generated. The DBA feature is not utilized, because both channels are used for every call. Make sure that your remote destination supports this functionality.

■ Add Second Channel As Required (recommended)

When this option is conﬁgured (referred to as bandwidth on demand), initially one modem channel is used to connect to a remote destination, and the second channel is automatically added when the amount of trafﬁc on the ﬁrst channel reaches a threshold that you deﬁne. When you choose Add Second Channel as Required, you enable both Multilink PPP and DBA. This is the recommended setting for Multilink PPP.

In order for you to use Multilink PPP, the destination you are calling must also support Multilink PPP. For example, if you are trying to dial out to the Internet, your ISP must support Multilink PPP in order to successfully place a Multilink PPP call. If you attempt to place a Multilink PPP call adding a “Second Channel as Required” and the location you are calling does not support Multilink PPP, then a single channel PPP connection is established. If you attempt to place a “Use Two Channels” call and the location you are calling does not support this functionality, a connection may not be established at all.

The Virtual FAX Modem (Windows 95, 98, NT, and 2000)

The Dual 56K LAN Modem can be used with the Virtual FAX Modem application (included on the OfﬁceConnect Dual 56K LAN Modem Companion Programs CD-ROM), which enables Windows users on the LAN to access one or both of the internal 56K modems as if they were directly connected to the user’s workstation through an RS-232 serial (COM) port.

By installing the Virtual FAX Modem application onto individual workstations connected to the LAN, users can run applications that call for a dedicated modem, such as a fax application for sending Class 2.0 faxes (Class 1 or Class 2 faxes are not supported) or connecting to Online services. Use of the two modems for Virtual FAX calls can be monitored by a network administrator through the Dual 56K LAN Modem’s Manual Call Control page.

Although both modems can be used at the same time to create two Virtual FAX Modem connections, each connection can support only one user at a time. In other words, a Virtual FAX Modem connection cannot be shared.

For instructions on installing and using the Virtual FAX Modem, and for information on monitoring Virtual FAX Modem calls through the Manual Call Control page, refer to Appendix B, “Installing and Using the Virtual FAX Modem.”

Support for Virtual Private Networks (VPNs) 29

Public telephone

network

Dual 56K LAN Modem

Workstation

with PPTP

client software

PPTP Tunnel

server

VPN tunnel

Corporate office

LAN



X L

OfficeConnect Dual 56k LAN Modem

LAN StatusMODEM 2MODEM 1

Internet

Support for Virtual Private Networks (VPNs)

Through its support of the Point-to-Point Tunnel Protocol (PPTP), the Dual 56K LAN Modem allows users on any workstation attached to the LAN Modem to communicate with a remote private network over the Internet using a Virtual Private Network (VPN) tunnel, provided the necessary client software is installed on the user’s workstation.

Although the LAN Modem allows for the transparent passage of VPN tunnel data from a computer on its LAN side to its WAN side, the LAN Modem cannot itself initiate or terminate a tunnel. In other words, the LAN Modem does not encrypt or encapsulate data on the outgoing side of the VPN connection, nor does it act as a tunnel terminator to unpack tunnel packets on the incoming side.

VPN tunnels are a private, secure means by which content-sensitive data that uses any routing protocol can be transported over the public, IP-routable-only Internet. Because a VPN tunnel is established through a local call to an Internet Service Provider, a user connecting to a remote Private Network through a VPN tunnel can eliminate long distance charges that might otherwise be incurred from dialing directly to the remote private network.

Figure 14 shows a VPN tunnel connection to a remote private network using a single, locally-dialed ISP call.

Figure 14 VPN Tunnel Connection to a Remote Private Network via an ISP

To create a VPN tunnel from a workstation attached to the Dual 56K LAN Modem, no special conﬁguration of the LAN Modem is required. The client workstation must, however, have the appropriate software, and a tunnel server must be set up at the remote private network.

Basic instructions for setting up and initiating a VPN tunnel from a client workstation are provided in Appendix C, “Creating a Virtual Private Network (VPN) Tunnel.”

30 CHAPTER 2: DUAL 56K LAN MODEM FUNCTIONALITY DESCRIPTION

+ 138 hidden pages