3COM 3C886 User Manual
OfficeConnect
®
®
56K LAN Modem
3C886
User Guide
http://www.3com.com/
Part No. 984/000027-2
Published March 1999
3Com Corporation
5400 Bayfront Plaza
Santa Clara, California
95052-8145
Copyright © 3Com Corporation, 1999. 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Unpublished rights reserved under the copyright laws of the United States.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 register ed in the United States and may or may
not be registered in other countries.
3Com and OfficeConnect are registered trademarks of 3Com Corporation.
IBM is a trademark of International Business Machines Corporation. Macintosh is a registered trademark of
Apple Computer Corporation. UL is a trademark of Underwriters Laboratory, Inc. Pentium is a registered
trademark of Intel Corporation. Windows and Windows NT are registered trademarks of Microsoft
Corporation. LZS is a registered trademarks of Stac, Inc. Compuserve is a registered trademark of
Compuserve Interactive Services, Inc. 3ComFacts is a service mark of 3Com.
Other brand and product names may be registered trademarks or trademarks of their respective holders.
Guide written by Eric Heller
Additional Safety Information
MPORTANT
I
AFETY
S
NFORMATION
I
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.
Use the power adapter supplied with the unit to ensure compliance with national safety
■
standards.
■
Disconnect the power adapter before moving the unit. Power can only be disconnected
from the unit by removing the power adapter from the unit or from the socket outlet.
There are no user-replaceable fuses or user-serviceable parts inside the unit. If there is a
■
physical 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.
Only connect apparatus complying with the relevant interface requirements to the ports on
■
this unit.
■
Retain this user’s guide for later use and pass it on in the event of change of ownership of
the unit.
Protect the unit from sudden, transient increases and decreases in electrical power by fitting
■
an in-line surge suppressor or uninterruptable 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.
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.
■
■
If the unit begins to make an odd noise, smell or smoke.
■
If the unit shows signs of a distinct change in performance.
Never install telephone wires during a lightning storm, or install telephone connection
■
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
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
■
the leak.
■
Do not spill food or liquids on the unit. If the unit gets wet, isolate the electrical supply and
contact your 3Com reseller.
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 telephone company can be connected to the
telephone port.
■
Avoid using a telephone, which is connected to the unit (other than a cordless type), during
an electrical storm.
■
Equipment connected to the telephone port must be located in the same building as the
unit.
■
Be sure nothing rests on the unit’s system cables and that the cables are not located where
they can be stepped on and cause damage to the unit.
Keep the unit away from radiators and heat sources. Allow 1 inch (25mm) around the unit
■
to provide adequate air circulation.
■
Install the unit in a clean area that is free from dust or extreme temperatures.
■
Allow a clearance gap of at least a 6 inches (150 mm) 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
requirements may produce hazardous conditions on the network. Advice should be sought
from a competent engineer before such a connection is made.
ABLE
T
MPORTANT
I
Additional Safety Information 3
A
BOUT
Introduction 11
How to Use This Guide 11
Conventions 11
Year 2000 Compliance 12
I
NTRODUCTION
1
Introduction 13
56K Access 13
Applications 13
Local Networking with Access to the Internet 14
Local Networking with Access to a Remote Office 14
Features 15
Ease of Installation and Use 15
High Performance 15
Connectivity 15
Routing 15
Bandwidth Management 15
Remote Management 15
Protocols 16
Error Control and Data Compression 16
Modulation Schemes 16
Security 16
Upgradability 16
Diagnostics 16
Warranty 17
Support for Internet Applications 17
T
HIS
OF
S
G
C
AFETY
UIDE
ONTENTS
NFORMATION
I
56K LAN M
2
F
UNCTIONALITY
Connection Types 19
56K Technology 19
LAN Side Connection 19
Application Sharing over the LAN 20
ODEM
D
ESCRIPTION
WAN Connection 21
One High Speed Connection 21
Sharing the Connection 21
Call Routing Protocol and IP Address Translation 22
Placing a Call to a Previously Defined Destination 22
Call Routing While No Other Calls are Connected 22
Understanding VPNs and PPTP 23
Setting Up the Server Side of the Tunnel 24
Setting Up the Client Side of the Tunnel 24
For Windows Dial-Up Networking Users 24
Establishing a Tunnel via the LAN Modem 24
3
H
ARDWARE
Package Contents 27
Before You Install the 56K LAN Modem 27
Front Panel LED Description 28
Back Panel Connector Description 29
Installing the 56K LAN Modem 29
Before You Begin 29
Installing the Analog Cable 30
Connecting to a 10BASE-T Ethernet Port 30
Connecting to Another Ethernet Hub 31
Before You Begin 31
Installing Analog Equipment 32
Installing the Power Cable 32
D
ESCRIPTION
AND
I
NSTALLATION
S
4
ETTING
TCP/IP Setup Using Windows 95 and 98 35
TCP/IP Setup Using Windows NT 4.0 38
TCP/IP Setup Using Mac OS 7.6 or later 41
TCP/IP Setup Using Windows 3.11 42
ONFIGURING
C
5
Typical Configuration 45
U
TCP/IP
P
Setting up TCP/IP using MS_TCP 42
THE
56K LAN M
Before You Begin 45
You Should Have This Information 46
Determine Whether You Use Dynamic or Static IP Addresses 46
Setting Up Your Computer If You Have a Static IP Address 47
For Windows 98 and 95 Users 47
For Windows NT 4.0 Users 47
For Macintosh Users 48
For Windows 3.11 Users 48
Configuring the 56K LAN Modem for the Typical Configuration 49
Configuring a Static IP Address on the 56K LAN Modem 52
Configure Additional Parameters 53
FOR
W
INDOWS
ODEM
AND
M
ACINTOSH
56K LAN Modem Main Page 54
Links From the Illustration 54
Links from the Buttons 55
6
DVANCED
A
Advanced Configuration 57
Setting Up Additional Service Providers 57
ISP Versus Private Network 58
When to Select ISP 58
When to Select Private Network 58
Setting Up a Connection to an ISP 58
Before You Begin 58
Setting Up a Connection to the Internet 59
Setting Up a Connection to a Private Network 62
Before You Begin 62
Setting Up a Connection to a Remote LAN 62
Associating Service Providers with Computers on the LAN 65
Editing Service Provider Profiles 66
Restricting Access to Service Providers 66
Configuring LAN Parameters 67
Understanding LAN Parameters 67
Name 67
IP Address and Subnet Mask 67
Local Domain Name 68
Enable DHCP Server 68
Enable NetBIOS Filtering 68
Configuring the LAN Parameters 68
Configuring Modem Control Parameters 69
Understanding Modem Controls 69
Connection Controls 69
Mode Controls 69
Protocol Controls 69
Changing Modem Controls 70
Changing Data Call Parameters 71
Understanding Data Call Parameters 71
Minimum Call Duration 71
Disconnecting an Automatic Data Call 71
Disconnecting a Manual Data Call 72
Number of Times to Redial for a Manual Call 72
Delay Between Redial Attempts When Placing a Manual Call 72
Configuring the Data Call Parameters 72
Selective Password Protection 72
Changing Your Password 73
What If I Forget My Password? 73
Locking and Unlocking the Configuration 73
Configuring the LAN Modem from a Remote Location 74
Configuring the LAN Modem Remotely via Another LAN Modem 74
ONFIGURATION
C
Configuring the LAN Modem Remotely via an Analog Modem 74
7
LACING
P
Placing Calls 77
Placing a Call Automatically 77
Call Routing Among Service Providers 77
Placing a Call Manually 78
Placing a Call Manually to a Temporary Service Provider 78
Receiving Calls 79
Receiving Voice Calls 79
Receiving Data Calls 79
Auto Answer 79
Disconnecting Calls 80
Disconnecting Calls Manually 80
Disconnecting Calls Automatically Using Timers 80
Minimum Call Duration 80
Idle Timeout 80
Using a Connection Script 80
Before You Begin 80
Accessing the Script Configuration Page 81
Creating a Connection Script 82
Connection Script Command Syntax 82
Using the Configuration Buttons 82
Additional Configuration Buttons 84
ECEIVING
, R
AND
ISCONNECTING
D
C
ALLS
8
T
ROUBLESHOOTING
Checking the Basics 85
Monitoring LEDs 85
Monitoring the ALERT LED 85
Monitoring the LAN Port Status LEDs 86
Evaluating Symptoms and Solutions 86
Finding More Information 90
Contacting Technical Support 90
Downloading Firmware to Your 56K LAN Modem 90
Resetting the 56K LAN Modem to a Factory Default Setting 90
Resetting the 56K LAN Modem to the Factory Defaults 90
Reviewing Statistics 91
Understanding System Statistics 91
Understanding Current Call Information 91
Understanding Last Call Information 92
Understanding Service Provider Information 93
AND
M
AINTENANCE
A
N
ETWORKING
P
RIMER
U
B
C
F
D
S
General Specifications 105
Year 2000 Compliance 105
G
3C
THE
D
C
USTOM
EFAULTS
SING
ACTORY
PECIFICATIONS
LOSSARY
OM CORPORATION LIMITED WARRANTY
W
EB
FCC CLASS B STATEMENT
FCC DECLARATION OF CONFORMITY
B
ROWSER
ABOUT THIS GUIDE
About This Guide provides an overview of this guide, describes guide conventions,
and tells you where to look for specific information.
Introduction This guide describes how to install and configure the 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 table shows where to find specific information in this guide.
This Guide
Table 1 Specific Information
If you are looking for... Turn to...
An overview of the 56K LAN Modem Chapter 1
An explanation of the 56K LAN Modem’s key functionality Chapter 2
A description of the 56K LAN Modem’s hardware components Chapter 3
Instructions on setting up TCP/IP Chapter 4
Instructions for basic configuration of the 56K LAN Modem software Chapter 5
Instructions for advanced configuration Chapter 6
Information on placing, receiving and disconnecting calls Chapter 7
Information on troubleshooting and maintenance Chapter 8
Background information on networking Appendix A
Information on using the custom browser Appendix B
56K LAN Modem factory default settings Appendix C
Technical specifications for the 56K LAN Modem Appendix D
Glossary definitions for terms used in this guide Glossary
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
12 ABOUT THIS GUIDE
Table 3 Text Conventions
Convention Description
Commands The word “command” means you must enter the command exactly as
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.
The words “enter”
and “type”
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.”
[Key] names Key names appear in text in one of two ways:
■ 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
and buttons
Words in italicized
type
Words in bold-face
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.
type
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
1
This chapter provides an overview of the OfficeConnect® 56K LAN Modem,
referred to throughout this document as the 56K LAN Modem or simply as the
LAN Modem.
Introduction The 56K LAN Modem is an easy to install, Local Area Network (LAN) to Wide Area
Network (WAN) personal analog IP router. The LAN Modem provides four built-in
10BASE-T Ethernet connections for the LAN, while utilizing the V.90 ITU 56K
standard for WAN access. Combining the 56K LAN Modem with an additional
external hub allows total WAN connectivity for up to 25 users.
With the 56K LAN Modem, small office and home office users can share remote
access to the Internet or to a corporate LAN while continuing to network locally.
56K Access 33.6 Kbps was once thought to be the practical limit for speed over standard
analog phone lines. Now, the V.90 56K ITU standar d pr ovides download speeds of
up to 56K.
upgrades to new features and enhancements as they become available.
1
And your 56K LAN Modem is software upgradable, allowing easy
For further information, visit 3Com’s 56K web site at
Applications The primary applications for the 56K LAN Modem are:
■ Local networking with shared access to the Internet
■ Local networking with shared access to a remote office LAN
1.Capable of receiving at up to 56 Kbps and sending at up to 33.6 Kbps. Due to FCC regulations, receiving speeds are limited to 53 Kbps. Actual speeds may vary . Requires compatible phone line and server equipment. The 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; ratification expected in September, 1998.
http://www.3com.com/56k.
14 CHAPTER 1: INTRODUCTION
Local Networking with
Access to the Internet
Users can share access to the Internet while continuing to network locally, as
shown in Figure 1.
PWR COLLPKT COAX1234
Alert
OfficeConnect
Hub 8 TPO
Port Status
5678
green = link OK, off = link fail, yellow = partition
Network Utilization
1%2% 3% 6% 12%25% 50%80%
3 Com
Office
¨
Connect
Hub
OfficeConnect
56K LAN modem
LAN STATUS
PWR
CD
Coll
AA
Tx
RD
OH
SD
Alert
OfficeConnect™
1
2 3 4
ISDN LAN Modem
3 Com
Analog POTS line
Internet/Intranet
online service
Public telephone
network
or
Local Networking with
Access to a Remote
Office
Figure 1 Local Networking with Internet Access
Users can share access to a remote office LAN while continuing to network locally,
as shown in Figure 2.
OfficeConnect™
56K LAN Modem
Figure 2 Local Networking with Access to a Remote Office LAN
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
High Performance
■ Internal 56K modem, capable of transmitting at speeds up to 33.6 Kbps and
downloading at speeds up to 56 Kbps
■ V.42/MNP 2-4 error control and V.42 bis/MNP 5 data compression
■ Hi/fn™ LZS
Compression Control Protocol (RFC 1962) and PPP Stacker LZS Compression
Protocol (RFC 1974)
Connectivity
■ One 56K integrated analog modem
■ Built in four-port 10BASE-T, 10 Mbps Ethernet hub. Up to 25 users can be
supported by connecting to an external eight port-hub
®
compression, which conforms to the following IETF RFCs: The PPP
1
(without compression)
Features 15
■ One pass through analog voice port for connecting an external analog device
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
■ Network Address Translation (NAT) between LAN and WAN, which allows
multiple users on the LAN to share a single remote connection
■ Multiplexing traffic from several computers to the same remote destination
■ LAN access to the Internet using a single-user account
Bandwidth Management
■ Dial on Demand (Automatic call connection)
■ Automatic disconnection of idle calls after a user-specified length of time
■ Manual call connection and disconnection
Remote Management
■ Remote management via Web browser-based interface
■ Remote firmware upgrades
1.Current FCC rules limit download speeds to 53Kbps.
16 CHAPTER 1: INTRODUCTION
Protocols
■ IETF PPP (RFC 1661, 1662, 1663)
■ 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)
Error Control and Data Compression
■ ITU-T V.42
■ ITU-T V.42bis
■ MNP 2-5
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
Upgradability
■ Flash memory for field firmware updates
■ Firmware posted on 3Com’s Web site
■ Fully upgradable to future 56K standards
Diagnostics
■ LED status display
■ Statistics display
Features 17
Warranty
■ 3Com Corporation Limited Warranty (refer to the end of this User Guide for
details)
Support for Internet Applications
Your 56K LAN Modem supports applications that use the User Datagram Protocol
(UDP) and the Transmission Control Protocol (TCP). This protocol is used primarily
by Internet games.
Look for the latest list of Internet applications and games that interoperate with
the LAN Modem at
http://www.remoteaccess.3com.com/support/docs/lanmodem/
welcome.html
18 CHAPTER 1: INTRODUCTION
56K LAN MODEM
2
Connection Types This section discusses LAN side and WAN side connections.
56K Technology Your 56K LAN Modem utilizes the V.90 56K ITU standard, which is backward
F
UNCTIONALITY DESCRIPTION
This chapter provides a description of the 56K LAN Modem’s key functionality,
covering the following topics.
■ Connection Types
■ Call Routing Protocol and IP Address Translation
■ Understanding PPTP
compatible with all US Robotics 56K standards, and is capable of download
speeds of up to 56K
configuration found when an analog modem dials into a digitally connected
Internet Service Provider. Because it requires no analog-to-digital conversions in
the downstream path (which can cause line noise), V.90 can use nearly all of the
available 64K network bandwidth. (Upstream data, typically less speed sensitive,
travels at the standard V.34 rate.)
1
. V.90 technology takes advantage of the typical network
Further information is available in Appendix A of this User Guide, or visit the 56K
web site at
LAN Side Connection On the LAN side, up to four users can connect to the 56K LAN Modem’s built in
Ethernet hub, or up to 25 users may connect to the 56K LAN Modem via an
external user-supplied hub, enabling users to share files and printers and to use
Internet email. An example of ten workstation connections is shown in Figure 3.
1.Capable of receiving at up to 56 Kbps and sending at up to 33.6 Kbps. Due to FCC regulations, receiving speeds limited to 53 Kbps. Actual speeds may vary. Requires compatible phone line and server
equipment. The 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; ratification expected in September, 1998.
http://www.3com.com/56k.
20 CHAPTER 2: 56K LAN MODEM FUNCTIONALITY DESCRIPTION
10 Mbps
Ethernet LAN
OfficeConnect
Hub 8 TPO
Port Status
PWR COLLPKT COAX1234
5678
Alert
green = link OK, off = link fail, yellow = partition
Network Utilization
1%2% 3% 6% 12%25% 50%80%
3 Com
Office
¨
Connect
Hub
LAN STATUS
Coll
Tx
AA
PWR
Alert
SD
CD
OH
RD
OfficeConnect
56KLAN Modem
3 Com
OfficeConnect®
1
2 3 4
56K LAN Modem
Figure 3 56K LAN Modem Ten Workstation Connection Example
An example of the minimum number of connections is shown in Figure 4.
3C886
56K LAN Modem
Figure 4 56K LAN Modem Minimum Connection Example
Application Sharing over the LAN
Most operating systems such as Windows 95, 98 and MacOS provide the
capability for LAN users to share applications, files and printers between
computers. For example, if only one computer has a Web browser, other LAN
users may share the browser for accessing the Internet. Note that speed will likely
be reduced when sharing applications. Refer to your operating system
documentation for instructions on setting up sharing between users on a LAN.
Connection Types 21
OfficeConnect
¤
56K LAN Modem
Public telephone
network
Remote office
LAN
Analog connection
3 Com
Oscar’s
Analog connection
Oscar’s PC
Felix’s PC
Murray’s PC
Myrna’s PC
connection
3C886
56K LAN Modem
PWRAA RD SD
Alert
Tx Coll 1 2 3 4 CD OH
LAN STATUS
OfficeConnect
¤
56K LAN Modem
Public telephone
network
Remote office
LAN
Shared analog connection
Mike
Single analog connection
Mike’s PC
Gloria’s PC
Edith’s PC
Archie’s PC
Gloria
3 Com
3C886
56K LAN Modem
PWRAA RD SD
Alert
Tx Coll 1 2 3 4 CD OH
LAN STATUS
WAN Connection The 56K LAN Modem allows up to 25 users to connect to a WAN using one
analog connection to a single location.
One High Speed
Connection
The WAN connection may be utilized by a single user to connect to a remote site
such as a corporate LAN, as shown in Figure 5.
Figure 5 Single User Connecting to a Remote Site
Sharing the Connection Once the call is established, up to four users may share the single connection
created by the call over the LAN Modem’s four-port built in hub. Or, up to 25 users
may share this connection over an external hub. Figure 6 shows two users on the
LAN accessing the Internet through the same Internet provider and over the same
connection. If you desire, you may also restrict access to certain users. Note that
speed may be affected with multiple users downloading simultaneously.
Figure 6 Shared Connection to a Remote Site
Your 56K LAN Modem is capable of supporting WAN access for up to 25 users.
However, for improved performance it is recommended that no more than four
users attempt to share a single connection at one time.
22 CHAPTER 2: 56K LAN MODEM FUNCTIONALITY DESCRIPTION
Call Routing Protocol and IP Address Translation
Placing a Call to a
Previously Defined
Destination
This section describes the call routing protocol used by the 56K LAN Modem and
explains how IP addresses are translated.
The 56K LAN Modem distinguishes between three types of destinations:
■ A direct connection to an Internet Service Provider
■ A direct connection to a Remote Office LAN
■ A direct connection to a Remote Office LAN with Internet Access
If all of these connection types are configured on the 56K LAN Modem and are
associated with your computer, the following algorithm is performed for each of
the following scenarios.
Call Routing While No Other Calls are Connected
If the 56K LAN Modem has not established any calls to a remote destination and
you want to access the Internet from your computer, you simply launch your Web
browser (or whichever networking application you like). When the 56K LAN
Modem receives the information packet requesting access to the WAN, it must
determine which connection type to use. The LAN Modem looks at the destination
Network ID (destination IP address and subnet mask) associated with the packet. If
the Network ID of the packet matches the Network ID of the Remote Office LAN,
with or without Internet access, then the call is placed to the remote LAN. If it
does not match the Network ID of the remote LAN, with or without Internet
access, then the call is routed to the direct ISP connection.
Once the connection is established, any authorized user on the LAN can use this
connection. The 56K LAN Modem will translate each individual user’s local IP
address into a single, shared IP address (assigned by the r emote location), allowing
shared access to the remote location. The following example shows three users
sharing a connection to the Internet and depicts the IP address translation as it
occurs in the LAN Modem.
Understanding VPNs and PPTP 23
From the Edge to the Heart
of the Network.
3
C
o
m
POWER
ISDN
Alert
B1
B2 TX COLL 1 2 3 4
3 Com
LAN STATUS
ISDN LAN Modem
3C892
OK
Internet Service
Provider
LAN Modem
Tunnel
terminator
Corporate
network
Understanding VPNs and PPTP
Jack’s PC
192.168.1.2
Chrissy’s PC
192.168.1.3
Larry’s PC
192.168.1.4
Janet’s PC
192.168.1.5
192.168.1.2
192.168.1.4
192.168.1.5
Translates PC IP
addresses to IP
address assigned
by ISP
LAN STATUS
PWRAA RD SD
Tx Coll 1 2 3 4 CD OH
Alert
OfficeConnect 56K LAN Modem
192.168.1.1
3C886
56K LAN Modem
IP address
assigned by ISP
198.6.1.1
3 Com
Analog POTS line
198.6.1.1
198.6.1.1
Public telephone
network
Internet/Intranet or
online service
198.6.1.1
Analog POTS line
Figure 7 IP Address Translation
Virtual private networks (VPN) are private, secure networks created in public
networks such as the Internet. A VPN is essentially a secure, private tunnel within
the Internet. Since VPN calls are placed through a local ISP, they eliminate long
distance charges that would occur from directly dialing to a remote private
network.
One of the protocols which enables a VPN to be created is PPTP. The PPTP protocol
allows for multiple workstations to establish a secure multi-protocol connection to
a remote, private network via a single, locally-dialed ISP account as shown in
Figure 8. Any networking protocols such as IP, IPX and NetBEUI can be supported
transparently through the tunnel. While the LAN Modem supports PPTP, it does
not play an active role in creating or terminating a tunnel.
Figure 8 Connection to an Remote Private Network via an ISP
24 CHAPTER 2: 56K LAN MODEM FUNCTIONALITY DESCRIPTION
The main steps for creating a VPN are as follows. Each step is explained in detail in
subsequent sections.
■ Set up the server side of the tunnel connection
■ Set up the client side of the tunnel connection
■ Initiate a tunnel between client and server using your client software
Setting Up the Server
Side of the Tunnel
Setting Up the Client
Side of the Tunnel
In order to establish a tunnel, the client side must be able to dial into a PPTP tunnel
server on the remote private network such as a Windows NT server version 4.0 or
later. If you use Windows NT 4.0, then Service Pack 3 or greater and RAS must be
installed. Also, the protocols required for the private network must be installed on
the PPTP tunnel server. It is recommended that an experienced network
administrator set up the server side. Note that protocols required for the private
network must be installed on each PPTP tunnel client as well as the PPTP tunnel
server.
In order to establish a tunnel, the client side must have PPTP tunnel client software
such as 3Com’s NETBuilder, PathBuilder, Total Control Hub. An additional
requirement is Microsoft’s Windows Dial-Up Networking version 1.2 or higher
which includes the required software VPN adapter, or Windows NT operating
system with Service Pack 3, or Network TeleSystem’s TunnelBuilder™ VPN
software for Windows 3.11 and Macintosh operating systems. This software
should reside on all workstations that wish to create a tunnel to the tunnel server.
Follow instructions provided for installation and set up.
For Windows Dial-Up Networking Users
If you are using Windows Dial-Up Networking version 1.2 or higher, the basic set
up steps are as follows. (Refer to Windows user documentation for details.)
■ Install the PPTP protocol
Establishing a Tunnel via
the LAN Modem
■ Create a RAS phone book entry for the VPN
A RAS phone book entry is similar to other phone book entries with the
exception of an IP address in the Phone number field. Once the Phone book
entry is complete, you can double-click the icon to dial into a server that
supports PPTP via any ISP.
Note that protocols required for the private network must be installed on each
PPTP tunnel client as well as PPTP tunnel server.
As with PPP, no configuration is required on the LAN Modem to use PPTP.
However, you must have an ISP configured on the LAN Modem.
Once the client side and server side are configured, you are ready to create a
tunnel. The steps required for creating a tunnel vary depending on which client
software you are using. Refer to the user documentation provided with your PPTP
software to determine how to establish a tunnel. For instance, if you are using
Windows Dial-Up Networking version 1.2 or higher, double-click the phone book
entry for the VPN.
Once you attempt to create a tunnel, the LAN Modem detects this attempt and
automatically places a call to your ISP. Once the call is connected, a tunnel is
established between your workstation and the tunnel server.
Understanding VPNs and PPTP 25
You are ready to access a remote private network LAN as if you were connected
locally. Each workstation that wishes to have access to the remote private LAN will
need to create its own tunnel.
Refer to
http://www.remoteaccess.3com.com/support/docs/lanmodem for more
information. For specific instructions on how to configure a VPN adapter in
Windows 98, 95 or Windows NT, refer to Microsoft’s Web site at
http://www.microsoft.com. and then enter PPTP in the search field.
26 CHAPTER 2: 56K LAN MODEM FUNCTIONALITY DESCRIPTION
HARDWARE DESCRIPTION AND
3
I
NSTALLATION
This chapter provides an overview of the hardware description and installation of
the 56K LAN Modem.
Package Contents The 56K LAN Modem package contents includes one of each:
■ OfficeConnect 56K LAN Modem
■ Power cable with an AC wall transformer
■ Analog telephone cable
■ 10BASE-T Ethernet cable
■ 3Com Companion Programs CD-ROM
■ OfficeConnect 56K LAN Modem Getting Started Guide
■ Rubber feet and stacking clips
Before You Install the 56K LAN Modem
To install, configure and use the 56K LAN Modem successfully, you must have the
following:
■ An available analog POTS (Plain Old Telephone Service) connection with an
available RJ-11 outlet.
■ A personal computer with TCP/IP and Ethernet connectivity that meets UL
standards in the United States or is certified to CSA standards in Canada.
■ For a PC, a 386 or higher processor is recommended and a 10BASE-T
Ethernet card is required.
■ For an Apple Macintosh computer , system 7.6 or later operating system and
Open Transport (included in System 7.6 or later). Built-in Ethernet
connectivity is provided through an Apple Ethernet port in all Power
Macintosh computers.
■ A frames-capable, JavaScript-enabled Web browser. A Web browser is required to
access and configure your LAN Modem and to view the OfficeConnect 56K LAN
Modem User Guide. You may use the customized browser provided on the 3Com
Companion Programs CD-ROM, or you may use any frames-capable Web browser,
such as Netscape Navigator (3.0 and later) or Microsoft Internet Explorer (3.0 and
later).
If you already have a version of Microsoft’s Internet Explorer W eb browser installed
and would like to install a later version, you should first uninstall the older version.
During installation, you may be asked to replace the older files. It is recommended
that you do so.
28 CHAPTER 3: HARDWARE DESCRIPTION AND INSTALLATION
■ TCP/IP software. TCP/IP is provided as part of the Windows 98, 95, NT and
Macintosh System 7.6 and later operating systems. For Windows 3.11 users,
TCP/IP software is provided on the 3Com Companion Programs CD-ROM.
Available storage space on your computer’s hard drive is not required because
nothing is installed onto your computer as part of the 56K LAN Modem setup
procedure. If you would like to copy any programs or documents from the
included CD-ROMs, ensure that you have available hard disk space.
Front Panel LED Description
The front panel provides the following LEDs.
LAN STATUS
PWR CDAA OH
Alert
RD SD TX COLL 1 2 3 4
Figure 9 56K LAN Modem Front Panel
56K LAN Modem
3C886
3 Com
The functions of the front panel LEDs are described in Table 4. These front panel
LEDs indicate proper operation and display 10BASE-T and analog port activity
status.
Table 4 Front Panel LED Indicator Definitions
LED Color Description
Alert Amber Operational Status. Lit during power-on self-diagnostic test or
PWR Green Power Indicator. Remains lit as long as power is supplied to the
AA Green Auto Answer. Indicates the 56K LAN Modem’s answer mode.
CD Green Carrier Detect. Remains lit if the 56K LAN Modem receives a valid
RD Green Received Data. Flashes when the LAN Modem receives data from
SD Green Send Data. Flashes when the LAN Modem sends data to a remote
OH Green Off Hook. Remains lit when the modem has gone off hook.
TX Green Ethernet Transmit Status. Flashes green when data is being
after pressing the reset button.
Off indicates 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.
unit.
Flashes during an incoming call.
Remains lit for the duration of the call.
Off when the LAN Modem originates a call.
data signal (carrier) from a remote modem (such as an ISP),
indicating that data transmission is possible.
a remote site.
site.
transmitted to the Ethernet LAN from the 56K LAN Modem .
Off indicates that no data is being transmitted to the Ethernet LAN
from the 56K LAN Modem.
Installing the 56K LAN Modem 29
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 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 provides the following components.
10-18 VDC
0.8 A MAX
Power
Connector
Figure 10 56K LAN Modem Back Panel
RESET
LINE PHONE
Reset Button
Telephone
Line
4
Analog
Device
Four Ethernet
10BASE-T Connectors
312
LAN
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 the unit.
■ Line: Connect the provided RJ-11 analog line from the wall outlet to this port.
■ Phone: Connect an external analog device, such as a telephone or fax
machine, to this port.
■ Four 10BASE-T Ethernet Ports: Connect the computers on your LAN, or an
external hub, to these ports.
Installing the 56K LAN Modem
Before You Begin Before you begin, you will need the following in addition to the 56K LAN Modem:
This section describes how to do the following.
■ Install the analog cable
■ Connect to a 10BASE-T Ethernet LAN
■ Install analog equipment
■ Install the power cable
■ RJ-11 (6-pin) to RJ-11 (6-pin) telephone cable which was provided in your
modem package.
30 CHAPTER 3: HARDWARE DESCRIPTION AND INSTALLATION
■ 10BASE-T Ethernet cable (8-pin to 8-pin connectors) labeled Ethernet which
was provided in the package. It is recommended that you use the cable
provided. However, if you choose to use another cable it must be a
straight-through 10BASE-T Ethernet cable. A crossover cable may not be used
to connect the LAN Modem to a workstation.
■ Power adapter (you must use the power adapter provided in the package).
Installing the Analog
Cable
Connecting to a
10BASE-T Ethernet Port
To install the analog cable:
1 Connect one end of the RJ-11 analog cable to the RJ-11 analog port labeled Line
on the 56K LAN Modem’s back panel, as shown in Figure 11.
LINE PHONE
RESET
10-18 VDC
0.8 A MAX
Figure 11 Analog Cable Connection
2 Connect the other end of the RJ-11 analog cable to a POTS analog wall jack.
To connect a computer to the 56K LAN Modem, do the following.
1 Insert one end of the 10BASE-T Ethernet cable into one of the four LAN ports on
the back of the 56K LAN Modem, as shown in Figure 12.
LINE PHONE
RESET
10-18 VDC
0.8 A MAX
Figure 12 10BASE-T Ethernet LAN Connection
2 Insert the opposite end of the cable into your computer’s 10BASE-T Ethernet port.
CAUTION: Connect only one computer to the 56K LAN Modem for initial
configuration. Once configuration is complete, you may connect the rest of the
computers to the LAN.
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