3com CoreBuilder 5000 Ethernet 36-Port 10BASE-T Module User Guide

CoreBuilder™ 5000

Ethernet 36-Port 10BASE-T Module User Guide

http://www.3com.com/

Document Number 17-00629-3 Published May 1997

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

Copyright © 3Com Corporation, 1997. 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. Portions of this document are reproduced in whole or part with permission from third parties.

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 products or programs 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.

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 the 3Com Corporation standard commercial agreement for the software. Unpublished rights reserved under the copyright laws of the United States.

If there is any software on removable media described in this documentation, it is furnished under a license agreement included with the product as a separate document, in the hardcopy documentation, or on the removable media in a directory file named LICENSE.TXT. If you are unable to locate a copy, please contact 3Com and a copy will be sent to you.

Federal Communications Commission Notice

This equipment was tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference, in which case you must correct the interference at your own expense.

Canadian Emissions Requirements

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.

Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.

EMC Directive Compliance

This equipment was tested and conforms to the Council Directive 89/336/EEC for electromagnetic compatibility. Conformity with this directive is based upon compliance with the following harmonized standards:

EN 55022 – Limits and Methods of Measurement of Radio Interference EN 50082-1 – Electromagnetic Compatibility Generic Immunity Standard: Residential, Commercial, and

Light Industry Warning: This is a Class A product. In a domestic environment, this product may cause radio interference, in

which case you may be required to take adequate measures. Compliance with this directive depends on the use of shielded cables.

Low Voltage Directive Compliance

This equipment was tested and conforms to the Council Directive 72/23/EEC for safety of electrical equipment. Conformity with this directive is based upon compliance with the following harmonized standard:

EN 60950 – Safety of Information Technology Equipment

VCCI Class 1 Compliance

This equipment is in the 1st Class category (information equipment to be used in commercial or industrial areas) and conforms to the standards set by the Voluntary Control Council for Interference by Information Technology Equipment aimed at preventing radio interference in commercial or industrial areas.

Consequently, when the equipment is used in a residential area or in an adjacent area, radio interference may be caused to radio and TV receivers, and so on.

Read the instructions for correct handling.

Fiber Cable Classification Notice

Use this equipment only with fiber cable classified by Underwriters Laboratories as to fire and smoke characteristics in accordance with Section 770-2(b) and Section 725-2(b) of the National Electrical Code.

UK General Approval Statement

The CoreBuilder 5000 Integrated System Hub and ONline System Concentrator are manufactured to the International Safety Standard EN 60950 and are approved in the U.K. under the General Approval Number NS/G/12345/J/100003 for indirect connection to the public telecommunication network.

Trademarks

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

3Com, Boundary Routing, CardFacts, EtherLink, LANplex, LANsentry, LinkBuilder, NETBuilder, NETBuilder II, NetFacts, Parallel Tasking, SmartAgent, TokenDisk, TokenLink, Transcend, TriChannel, and ViewBuilder are registered trademarks of 3Com Corporation.

3TECH, CELLplex, CoreBuilder, EtherDisk, EtherLink II, FDDILink, MultiProbe, NetProbe, and ONline are trademarks of 3Com Corporation.

3ComFacts is a service mark of 3Com Corporation. The 3Com Multichannel Architecture Communications System is registered under U.S. Patent

Number 5,301,303. AT&T is a registered trademark of American Telephone and Telegraph Company. Banyan and VINES are registered trademarks of Banyan Systems Inc. CompuServe is a registered trademark of CompuServe, Inc. DEC, DECnet, DELNI, POLYCENTER, VAX, VT100, VT220, and the Digital logo are trademarks of Digital

Equipment Corporation. Hayes is a registered trademark of Hayes Microcomputer Products. OpenView is a registered trademark of Hewlett-Packard Company. Intel is a registered trademark of Intel Corporation. AIX, IBM, and NetView are registered trademarks of International Business Machines Corporation. Microsoft, MS-DOS, Windows, Windows 95, and Windows NT are registered trademarks of

Microsoft Corporation. V30 is a trademark of NEC Corporation. NetWare and Novell are registered trademarks of Novell, Incorporated.

IPX is a trademark of Novell, Incorporated. OSF and OSF/Motif are registered trademarks of Open Software Foundation, Inc. ONC, OpenWindows, Solaris, Solstice, Sun, Sun Microsystems, SunNet Manager, and SunOS are trademarks

of Sun Microsystems, Inc.

iii

SPARCstation is a trademark licensed exclusively to Sun Microsystems Inc. OPEN LOOK is a registered trademark of Unix System Laboratories, Inc. UNIX is a registered trademark of X/Open Company, Ltd. in the United States and other countries. Other brand and product names may be registered trademarks or trademarks of their respective holders.

HOW TO USE THIS GUIDE

Audience 1 Structure of This Guide 2 Document Conventions 3 Related Documents 4

3Com Documents 4 Reference Documents 4

1 INTRODUCTION

36-Port 10BASE-T Module Description 1-2 36-Port 10BASE-T Module Features and Benefits 1-2 Theory of Operation 1-5

Sample Module Application 1-5

2 DESIGNING AND EXPANDING THE NETWORK

Understanding General Network Configuration Rules 2-1

Before Configuring Your Network 2-2 Basic Network Rules 2-2 LAN Equivalent Requirements 2-4

Configuring Fiber Backbone, Twisted Pair to-the-Desk 2-5

Fiber Backbone Configuration Rules 2-5 Fiber Backbone, Twisted Pair to-the-Desk Configuration Example 2-6 Verifying Fiber Backbone Configuration 2-7

Configuring Twisted Pair Backbone, Twisted Pair to-the-Desk 2-7

Twisted Pair Backbone Configuration Rules 2-8 Twisted Pair Backbone, Twisted Pair to-the-Desk Configuration

Example 2-8 Determining Fiber Equivalent Distance 2-9

Using Patch Panels 2-9

Using Module Workgroups 2-10

Workgroup Definition 2-10 Dividing the Network into Workgroups 2-11

Setting Redundant Links 2-15

Setting Redundancy Between Two Ports on One 36-Port 10BASE-T Module 2-16

Setting Redundancy Between Ports on Two 36-Port 10BASE-T Modules 2-16

3 INSTALLING AND OPERATING THE MODULE

Precautionary Procedures 3-2 Unpacking Procedures 3-2 Quick Installation 3-3 Setting DIP Switches 3-4

DIP Switch Features 3-4 Setting the DIP Switches 3-4 DIP Switch Definition 3-5

Installing the Module 3-7

Attaching the Tie-Wrap Bracket 3-11

Before You Begin 3-11

Configuring the Module 3-14

Configuration Overview 3-14 Set Port Mode Commands 3-15

Enable/Disable/Shutdown Ports Command 3-15 Setting Port Redundancy Command 3-15

Setting Remote Diagnostics Command 3-16 Enable/Disable Link Integrity Command 3-16 Set Port Alert Filter Command 3-16 Set Port Auto Polarity Command 3-17 Network Selection 3-17

Assigning Connectors on the Module to a Network 3-18

Assigning a Monitor Card to a Network 3-18

Showing Module Configurations 3-19

Show Module Command 3-19 Show Port Command 3-19

Connecting Module Daughter Cards 3-21

Gathering Statistics 3-23

Repeater Statistics 3-23 Ethernet and RMON Statistics 3-23

Monitoring Network Statistics 3-24

Monitor Command 3-24 Show Counter Command 3-25

Monitoring the Front Panel 3-27

Module Status LED 3-27 Port Status and Activity LEDs 3-27

Verifying LED and Network Operation 3-29

Using the CoreBuilder 5000 Controller Module to Verify Bicolor LED Operation 3-30

Using the DMM to Verify Network Connections 3-30

Verifying Network Connections for the 36-Port 10BASE-T Module 3-31

4 TROUBLESHOOTING

Troubleshooting Using the Module Status LED 4-1 Troubleshooting Using the Port Status LEDs 4-2 Technical Assistance 4-3

A SPECIFICATIONS

Electrical Specifications A-1 Environmental Specifications A-1 Mechanical Specifications A-2 General Specifications A-2 50-Pin Connector and Cable A-3 Twisted Pair Connectors and Cables A-5

Twisted Pair Connectors A-5 Twisted Pair Cables A-6

Connecting Twisted Pair Cables A-6

vii

B TECHNICAL SUPPORT

Online Technical Services B-1

World Wide Web Site B-2 3Com Bulletin Board Service B-2

Access by Analog Modem B-2

Access by Digital Modem B-2 3ComFacts Automated Fax Service B-3 3ComForum on CompuServe Online Service B-3

Support From Your Network Supplier B-4 Support From 3Com Corporation B-5 Returning Products for Repair B-6 Accessing the 3Com MIB B-6 Contacting 3Com Technical Publications B-7

INDEX

3COM CORPORATION LIMITED WARRANTY

viii

FIGURES

1-1 CoreBuilder 5000 Ethernet 36-Port 10-BASE-T Module Faceplate 1-4 1-2 Sample 36-Port 10BASE-T Module Application 1-5 2-1 Sample Configuration Distance Calculation 2-6 2-2 Twisted Pair Network 2-8 2-3 Typical Corporate Organizational Structure 2-11 2-4 36-Port 10BASE-T Module Workgroup Port Allocation 2-13 2-5 Redundant Twisted Pair Configuration 2-15 3-1 36-Port 10BASE-T Module DIP Switch Location 3-5 3-2 Installing a CoreBuilder 5000 Module 3-8 3-3 Opened and Closed Module Ejectors 3-9 3-4 50-Pin Connector Cable Connection 3-10 3-5 Attaching the Tie-Wrap Bracket to the 36-Port Module 3-12 3-6 Attaching Cables With 90° Connectors 3-13 3-7 Attaching the CoreBuilder 5000 Ethernet Monitor Card 3-22

3-8 36-Port 10BASE-T Module Faceplate 3-28 A-1 50-Pin Cable Male and Female Connectors A-3 A-2 RJ-45 Connector Pinouts A-5

TABLES

2-1 Seven Basic Network Rules 2-2

2-2 LAN Product Equivalent Distances 2-4

2-3 Sample Network Reorganization 2-12

3-1 Quick Installation Checklist 3-3

3-2 Network Selection DIP Switch Settings 3-6

3-3 36-Port 10BASE-T Module LED Interpretations 3-29

4-1 Module Status LED Troubleshooting 4-1

4-2 Port Status LED Troubleshooting 4-2 A-1 50-Pin Cable Pinouts and Port Assignments A-4

HOW TO USE THIS GUIDE

This guide explains how to install and operate the 3Com CoreBuilder information on monitoring the module using the 3Com CoreBuilder 5000 Distributed Management Module. An appendix explains cabling guidelines, specifications, and options for the Ethernet 36-Port 10BASE-T Module.

Before installing or using the 36-Port 10BASE-T Module, read Chapters 1, 2, and 3 of this guide for basic installation and operating instructions.

™

5000 Ethernet 36-Port 10BASE-T Module. It also includes

Audience This guide is intended for the following people at your site:

■ Network manager or administrator

■ Hardware installer

2 HOW TO USE THIS GUIDE

Structure of This Guide

This guide contains the following chapters:

Chapter 1, Introduction – Introduces the functions and features of the Ethernet 36-Port 10BASE-T Module.

Chapter 2, Designing and Expanding the Network – Shows possible network configurations using the CoreBuilder 5000 Integrated System Hub and the 36-Port 10BASE-T Module.

Chapter 3, Installing and Operating the Module – Provides illustrated procedures for installing the 36-Port 10BASE-T Module into the CoreBuilder 5000 hub. Also shows front panel LEDs and DIP switches on the module and describes network management commands.

Chapter 4, Troubleshooting – Provides help in isolating and correcting problems that may arise when installing or operating this module.

Appendix A, Specifications – Provides electrical, environmental, and mechanical specifications for the module. In addition, this appendix provides information on 50-pin Telco-type connectors, RJ-45 connectors, and twisted pair cables.

Appendix B, Technical Support – Lists the various methods for contacting the 3Com technical support organization and for accessing other product support services.

Index

Document Conventions 3

Document Conventions

The following document conventions are used in this manual:

Convention Indicates Example

Courier text User input In the Agent Information Form,

enter MIS in the New Contact field.

System output After pressing the Apply button, the

Bold command string Path names Before you begin, read the

Text in angled brackets User-substituted

identifiers

Capitalized text in plain brackets

Italics Text emphasis,

Icon Notice Type Alerts you to...

Information note Important features or instructions

Keyboard entry by the user

document titles

system displays the message Transmitting data.

readme.txt file located in

/usr/snm/agents.

In the command above, substitute <rem_name> with the name of the remote machine.

Type your password and press [ENTER].

Ensure that you press the Apply button after you add the new search parameters.

Caution Risk of personal safety, system damage, or loss

of data

Warning Risk of severe personal injury

4 HOW TO USE THIS GUIDE

INTRODUCTION

This chapter describes the 3Com CoreBuilder™ 5000 Ethernet 36-Port 10BASE-T Module (Model Number 6136M-TPCL). For more information on the 3Com refer to the CoreBuilder 5000 Integrated System Hub Installation and Operation Guide.

The Ethernet 36-Port 10BASE-T Module requires the Distributed Management Module (DMM) Version 2.2 or later for full functionality.

This chapter contains the following sections:

■ 36-Port 10BASE-T Module Description

■ 36-Port 10BASE-T Module Features and Benefits

■ Theory of Operation

CoreBuilder 5000 Integrated System Hub,

1-2 CHAPTER 1: INTRODUCTION

36-Port 10BASE-T Module Description

36-Port 10BASE-T Module Features and Benefits

The 36-Port 10BASE-T Module is a connector-switching module which:

■ Supports Telco 50-pin connector-based 10BASE-T wiring

■ Enables users to assign a backplane segment at the connector level

of the module

■ Connects up to 36 devices (PCs, terminals, printers, modems) to

the 3Com CoreBuilder 5000 Integrated System Hub

■ Provides 36 10BASE-T-compliant ports using 25-pair 10BASE-T cables

or 12-leg hydra cables

The CoreBuilder 5000 Ethernet 36-Port 10BASE-T Module provides the following features:

■ Checks driver and receiver integrity using Remote Diagnostics Mode.

■ Supports security through the CoreBuilder 5000 Private Line Card

(PLC). The PLC provides continuous eavesdropping and intrusion protection without affecting network performance.

■ Allows you to connect up to two CoreBuilder 5000 Network

Monitor Cards for network management.

■ Allows you to install or remove the module without having to power

down the hub.

■ Supports scalable network management architecture which enables

you to gather Ethernet and Remote Network Monitoring (RMON) network statistics for any of the CoreBuilder 5000 backplane segments.

Each module supports two daughter cards including a Network Monitor Card (NMC) for in-depth monitoring of the network or a Private Line Card for private Ethernet conversations.

■ Provides easy configuration using the CoreBuilder 5000 Manager.

■ Supports three 12-port Telco 50-pin connectors which you can

switch (per connector) to any of the eight CoreBuilder 5000 hub backplane channels or eight extended segments in any combination of eight.

■ Provides per-connector switching to all eight of the

CoreBuilder 5000 hub backplane segments and eight isolated segments.

36-Port 10BASE-T Module Features and Benefits 1-3

■ Provides IEEE Repeater statistics gathering for monitoring of the

CoreBuilder 5000 hub’s security and network management architecture.

■ Offers high port density at a low cost per port.

■ Supports up to 100 meters on 10BASE-T-compliant unshielded

twisted pair (UTP) wiring as well as shielded twisted pair (STP) wiring.

■ Provides connector-switching connectivity for STP and UTP 10BASE-T

networks.

■ Maintains inventory information for the 36-Port 10BASE-T Module in

non-volatile RAM (NVRAM). Information includes the module serial number, power requirements, power class settings (for example, powerup priority), and date of manufacture and a user note pad for entering installation-specific information.

■ Supports CoreBuilder 5000 hub power management architecture

which enables administrators to prioritize the allocation of power to modules.

In addition, the 36-Port 10BASE-T Module supports Repeater Management Information Base (MIB) statistics without the need for a network monitor card.

1-4 CHAPTER 1: INTRODUCTION

Figure 1-1 illustrates the CoreBuilder 5000 36-Port 10BASE-T Module.

MODULE

STATUS

1 4

13 16 19 22

25 28 31 34

Module Status LED

Bi-color Status/Activity Status LEDs

1X-12X

50-pin connector (ports 1 to 12)

13X-24X

50-pin connector (ports 13 to 24)

25X-36X

50-pin connector (ports 25 to 36)

6136M-TPCL

Figure 1-1 CoreBuilder 5000 Ethernet 36-Port 10-BASE-T Module Faceplate

Theory of Operation 1-5

Theory of Operation

Sample Module

Application

The 36-Port 10BASE-T Module is a connector-switching Ethernet module that enables administrators to connect up to 36 network devices to the module using a patch panel or punch-down block for each Telco 50-pin connector.

You can attach the workstations in Figure 1-2

to the 36-Port 10BASE-T Module using a patch panel or punch-down block that is directly connected to the Telco 50-pin connectors on the 36-Port 10BASE-T Module. Each Telco 50-pin connector provides 12 twisted pair ports that enable you to connect up to 12 workstations (per connector) to the 36-Port 10BASE-T Module.

36-Port 10BASE -T Module

CoreBuilder 5000 Integrated System Hub

Patch

Workstation

Tel co-to-RJ45 connections

Figure 1-2 Sample 36-Port 10BASE-T Module Application

DESIGNING AND EXPANDING THE

NETWORK

This chapter describes how to configure networks that use the CoreBuilder Ethernet 36-Port 10BASE-T Module.

This chapter contains the following sections:

■ Understanding General Network Configuration Rules

■ Configuring Fiber Backbone, Twisted Pair to-the-Desk

■ Configuring Twisted Pair Backbone, Twisted Pair to-the-Desk

■ Using Patch Panels

■ Using Module Workgroups

■ Setting Redundant Links

CAUTION: To ensure proper operation, install all equipment using only approved cables. Refer to Appendix A on twisted pair connector and cable requirements.

™

5000 Integrated System Hub and the CoreBuilder 5000

, Specifications, for information

Understanding General Network Configuration Rules

This section describes general rules for configuring an Ethernet network using fiber as the backbone medium, and twisted pair as the horizontal medium (connection to printers, computers). It also provides rules to ensure that your network configuration conforms to distance limitations imposed by Ethernet and networking equipment.

The following topics are discussed:

■ Before Configuring Your Network

■ Basic Network Rules

■ LAN Equivalent Requirements

2-2 CHAPTER 2: DESIGNING AND EXPANDING THE NETWORK

Before Configuring

Before configuring your network, consider your:

Your Network

■ Network size from end-to-end:

■ 100 meters

■ 1000 meters

■ 4000 meters

■ Greater than 4000 meters

■ Plans for expansion. Once the network expands beyond a certain

size, you may need to add an Ethernet switch or an additional internetworking device.

Basic Network Rules Table 2-1

■ Seven basic network rules to keep in mind when you construct

your network

■ 3Com

For hardware-specific information on the Ethernet 36-Port 10BASE-T Module, refer to Appendix A

Table 2-1 Seven Basic Network Rules

lists:

Corporation’s recommendations for these rules

, Specifications.

Rule Definition Recommendations/Notes 1 If possible, use 10BASE-FB

as the backbone medium.

Use 62.5 micron cable to conform with IEEE 10BASE-F and ANSI FDDI standards.

Use ST-type connectors.

2 Wire the backbone in a star

topology for proper fault isolation.

Make sure to lay extra fiber cables. The extra cost is small and you need them as your network grows.

The star topology conforms to Ethernet and FDDI wiring. Ensure that you run at least two FDDI fiber strands to each backbone connection.

Understanding General Network Configuration Rules 2-3

Table 2-1 Seven Basic Network Rules (continued)

Rule Definition Recommendations/Notes 3 The maximum fiber Ethernet

network diameter is 4200 meters of fiber cable.

4 Certain LAN devices on the

network shrink the maximum Fiber Ethernet network diameter to less than 4200 meters.

5 Assume that 1 meter of

coaxial or twisted pair cable is equal to 1 meter of fiber cable.

6 The fiber link distances must

not exceed the limits imposed by the optical power budget.

7 When in doubt, use a switch

or bridge.

4200 meters is the maximum distance between any two transceivers on the network.

4200 meters does not include the transceiver cable (that is, drop or patch cable) that connects a device with an external transceiver. Transceiver cables can extend up to 50 meters. Thus, total network diameter can be as much as 4300 meters (4200 m + 2 * 50 m) between any two nodes.

Many LAN products delay the signal that travels through them. This is known as equivalent distance. Each microsecond delay:

Reduces the maximum link distance Shrinks the network diameter by

approximately 200 meters of fiber cable

Table 2-2

3Com products. A conservative rule. For example, the

actual equivalence is about 1.1 meters of coaxial for each meter of fiber. For simplicity, assume 1 meter.

For 62.5 micron cable, you can utilize up to 4000 meters point-to-point using CoreBuilder 5000 or ONline Fiber Modules. If you have poor quality cable or cross several patch panels, you may have to sacrifice some distance in cable length.

Some older Ethernet fiber optic products are less powerful than CoreBuilder 5000 Fiber Module optics. If connecting to an Ethernet fiber optic product, remember that the least powerful device determines the maximum point-to-point distance.

If you are not certain if you have exceeded allowable network distances, use a bridge to extend the network.

lists equivalent distances for

2-4 CHAPTER 2: DESIGNING AND EXPANDING THE NETWORK

LAN Equivalent

Requirements

LAN equivalence is the sum of the incoming and outgoing module port signals. When you configure your network, consider that each installed product reduces the network diameter.

Table 2-2

lists the LAN product equivalent distances required for each

LAN product.

Table 2-2 LAN Product Equivalent Distances

Equivalent

LAN Product

CoreBuilder 5000 and ONline Ethernet 10BASE-T Modules 585

Incoming signal to TP port 420 Outgoing signal from TP port 165

CoreBuilder 5000 and ONline Ethernet 10BASE-FB Modules 190

Incoming signal to fiber port 140 Outgoing signal from fiber port 50

ONline Ethernet FOIRL Modules 560

Incoming signal to fiber port 330

Outgoing signal from fiber port 230 CoreBuilder 5000 and ONline Ethernet Transceiver Modules 0 10BASE-FB Star Coupler (8 or 14 port) 180 CoreBuilder 5000 and ONline Ethernet BNC Modules 900

Incoming signal to BNC port 450

Outgoing signal from BNC port 450 CoreBuilder 5000 and ONline Ethernet Repeater Modules 800

Incoming signal to AUI port 600

Outgoing signal from AUI port 200 IEEE Repeater 800

Distance (meters)

Configuring Fiber Backbone, Twisted Pair to-the-Desk 2-5

Configuring Fiber Backbone, Twisted Pair to-the-Desk

Fiber Backbone

Configuration Rules

This section describes:

■ Fiber Backbone Configuration Rules

■ Fiber Backbone, Twisted Pair to-the-Desk Configuration Example

■ Verifying Fiber Backbone Configuration

When you configure a network with unshielded twisted pair cabling to the desk and fiber for the backbone, the following rules apply:

■ Add a bridge if you will exceed 4 full repeater hops.

■ If traffic travels into a port on any repeater-based module and

out the backplane, then the module counts as a ½-repeater hop.

■ If traffic travels into the module through one port and out

another port on the same or a different module, then the module counts as 1 full repeater hop.

■ The equivalent fiber distance for the 3Com Ethernet 10BASE-FB

Modules (see Table 2-2

■ 140 meters for signals that enter a 10BASE-FB Module port at

) is:

the front panel.

■ 50 meters for signals that internally enter a 10BASE-FB Module

through the CoreBuilder 5000 hub backplane.

■ The equivalent fiber distance for the Ethernet 36-Port 10BASE-T

Modules (see Table 2-2

■ 420 meters for signals that enter the Ethernet 36-Port 10BASE-T

) is:

Module port at the front panel.

■ 165 meters for signals that internally enter an Ethernet 36-Port

10BASE-T Module through the CoreBuilder 5000 hub backplane.

For each pair of Ethernet 36-Port 10BASE-T Modules that a signal travels through, deduct a fiber equivalent distance of 585 meters (420 m + 165 m = 585 m) from the overall allowable network diameter. You must also deduct fiber equivalent distance if a signal enters the Ethernet 36-Port 10BASE-T Module through one port and exits another port of the same Ethernet 36-Port 10BASE-T Module. The fiber equivalent distance counts as 585 meters of fiber equivalent distance and as a full repeater hop.

2-6 CHAPTER 2: DESIGNING AND EXPANDING THE NETWORK

Fiber Backbone,

Twisted Pair

to-the-Desk

Configuration

Example

Fiber backbone

1000 m

The sample configuration shown in Figure 2-1 uses 10BASE-T modules to connect to the transceivers A and B. Refer to the next section for a detailed explanation of configuration distances.

The 24-gauge unshielded twisted pair cable is used to connect 10BASE-T Transceivers to the Ethernet 36-Port 10BASE-T Modules in the hubs.

2 4

500 m

Fiber backbone

2 4

Hub A

Hub B

Hub C

Unshielded twisted pair

100 m

Unshielded twisted pair

75 m

Unshielded twisted pair

Configuration Distance

1. Maximum Diameter:

2. Equivalent Distances: Hub A:

Hub B: Hub C:

Total:

3. Amount of cable between

transceivers:

Total:

4. Remaining Distance:

470 m 305 m 190 m

965 m

1000 m 100 m 500 m 75 m

4200 m

1675 m

1560 m

Figure 2-1 Sample Configuration Distance Calculation

Configuring Twisted Pair Backbone, Twisted Pair to-the-Desk 2-7

Verifying Fiber

Backbone

Configuration

To determine if your network configuration is legal:

1 Begin with 4200 meters. 2 Identify the two transceivers (A and B) that are the greatest fiber

equivalent distance apart. In Figure 2-1

, 10BASE-T transceivers A and B

are the farthest apart.

3 Determine the sum of each hub’s equivalent distance using the

distances listed in Table 2-2

. For example, Hub A has an equivalent distance of 470 m. This total represents the sum of the incoming signal to the UTP port (420 m) and the outgoing signal from the fiber port (50 m). Refer to Figure 2-1

for details.

4 Subtract the total equivalent distance of each hub located between

transceivers A and B (965 m) from the maximum network diameter (4200 m). In this case, the subtotal is 3235 m.

5 Determine the total amount of cable between transceivers A and B

(1675 m) and subtract this number from the subtotal determined in step 4

(3235 m).

The remaining distance for legal expansion equals 1560 m.

For the configuration shown in Figure 2-1

to function properly, the fiber equivalent distance between Transceiver A and Transceiver B must be less than 4200 meters. As a result of the calculation above, 1560 meters remain for expansion.

Configuring Twisted Pair Backbone, Twisted Pair to-the-Desk

This section describes:

■ Twisted Pair Backbone Configuration Rules

■ Twisted Pair Backbone, Twisted Pair to-the-Desk Configuration

Example

■ Determining Fiber Equivalent Distance

+ 67 hidden pages

3com CoreBuilder 5000 Ethernet 36-Port 10BASE-T Module User Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

CONTENTS

FIGURES

TABLES

HOW TO USE THIS GUIDE

Audience This guide is intended for the following people at your site:

Structure of This Guide

Document Conventions

Related Documents This section provides information on supporting documentation,

■ 3Com Documents

■ Reference Documents

INTRODUCTION

36-Port 10BASE-T Module Description

36-Port 10BASE-T Module Features and Benefits

Theory of Operation

Understanding General Network Configuration Rules

Basic Network Rules Table 2-1

■ Fiber Backbone Configuration Rules