3Com 5104M-FL1 User Manual

ONline Ether net 10BASE -FL

Module Installation and

Operation Guide

Document Number 17-00470-3

Printed March 1995

Model Number: 5104M-FL1

3Com Co rporation 118 Turnpike Road

Southbo rough, MA 0177 2-1886

U.S.A.

(508) 46 0- 8900

FAX (508) 460-8950

Federal Communications Comm ission Notice

This equipment has been 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 i s 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 rad io communications. Operation of this equipment in a residential area is likely to cause harmful interfer ence, in which case you must correct the interference at your own expense.

Canadian Emissions Requirements

Cet appareil numérique respecte les limites de bruits radioélectriques applicables aux appareils numériques de Classe A prescrites dans la norme sur la matériel brouilleur: "Appareils Numériques", NMB-003 édictée par le Ministère des Communications.

This digital apparatus does not exceed the Class A limits for radio noise emissions from digital apparatus as set out in the interference-causing equipment standard entitled "Digital Apparatus", ICES-003 of the Department of Communications.

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 V oluntary Control Council for Inter fere nce 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, r adio interferenc e 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 cable classified by Underwriters Laboratories as to fire and smoke char acteristics in accordance with Section 770-2(b) and Section 725-2(b) of the National Electrical Code.

VDE Class B Compl ianc e

Hiermit wird bescheinigt, dass der 5104M-FL1 in Üebereinstimmung mit den Bestimmungen der Vfg 243/1991 funkentstöert ist.

Der Deutschen Bundespost wurde das Inverkehrbringen dieses Geraetes angezeigt und die Berechtigung zur Üeberprüefung der Serie auf Einhaltung der Bestimmungen eingeräeumt.

Einhaltung mit betreffenden Bestimmugen kommt darauf an, dass geschirmte Ausfuehrungen gebraucht werden. Fuer die Beschaffung richtiger Ausfuehrungen ist der Betreiber verantwortlich.

This is to certify that the 5104M-FL1 is shield ed against radio interference in accordance with the provisions of Vfg 243/1991.

The German Postal Services have been advised that this equipment is being placed on the market and that they have been given the right to inspect the series for compliance with regulations.

Compliance with applicable regulations depends on the use of shielded cables. The user is responsible for procuring the appropriate cables.

EN55022/CISPR22 Com p lian ce

This equipment conforms to the Class A emissions limits for a digital device as defin ed by EN55022 (CISPR22).

UK General Approval Statem en t

The ONcore Switching Hub, ONline System Concentrator, and ONsemble StackSyste m Hub are manufactur ed to the International Safety Standard EN 60950 and are approve d in the UK under the Genera l Approval Number NS/G/12345/J/100003 for indirect connection to the public telecommunication network.

Disclaimer

The information in this document is subject to change without notice and should not be construed as a commitment by 3Com Corporation. 3Com Corporation assumes no responsibility for any errors that may appear in this document.

1995, by 3Com Corporation. Printed in U.S.A. All rights r eserved. 3Com is a registered trademark of 3Com Corporation. The information contained herein is the exclusive and confidential property of 3Com Corporation. No part of this manual may be disclosed or reproduced in whole or in part without permission from 3Com Corporation.

Trademarks

Because of the nature of this material, numerous hardware and software products are mentioned by name. In most, if not all cases, these product names are claimed as trademarks by the companies that man ufacture the products. It is not our intent to claim these names or trademarks as our own.

ii ONline Ethernet 10BASE-FL Module Installation and Operation Guide

Artel, Chipcom, Ethermodem, Galactica, ONcore, ORnet, StarBridge, and TriChannel are regi stered trademarks of 3Com Corporation.

Chipcom OpenHub, G-Man, LANsentry, MultiProbe, ONdemand, ONline, ONsemble, PowerRing, SL2000, SL3000, SL40 00, StackJack, StackSystem, and SwitchC entral are trademarks of 3Com Corporation.

The Chipcom Multichannel Architecture Communications System is registered under U.S. Patent Number 5,301,303.

DEC, DECnet, the Digital logo, DELNI, POLYCENTER, VAX, VT100, and VT220 are trademarks of Digital Equipment Corporation.

IBM is a registered trademark of International Business Machines. Restricted Rights

XNS is a trade mark a nd Ethernet is a r egistered trademark of Xerox Corporation.

3ComFacts, Ask 3Com, CardFacts, NetFacts, and CardBoard are service marks of 3Com Corporation.

3Com, LANplex, BoundaryRouting, LanScanner, LinkBuilder, NETBuilder, NETBuilderII, ParallelTasking, ViewBuilder, EtherDisk, Etherl\Link, Ether Link Plus, EtherLink II, TokenLink, T okenLink Plus, and TokenDisk are registered trademarks of 3Com Corporation.

3ComLaser Library, 3TECH, CacheCard, FDDILink, FMS, NetProbe, SmartAgent, Star-Tek, and Transcend are trademarks of 3Com Corporation.

CompuServe is a registered trademark of CompuServe, Inc. 3Com registered trademarks are registered in the United States,

and may or may not be register ed i n other countrie s. Other brand and product names may be reg istered tradema rks or trademark s of their respective holders.

Use, duplication, or disclosure by the Government is s ubject to restrictions as set forth in subparagraph (c)(1) (ii) of the Rights in Technical Data and Computer Software clause at DFARS 252.227-7013.

Printed on recycled paper.

ONline Ethernet 10BASE-FL Module In st al lation and Operation Guide iii

iv ONline Ethernet 10BASE-FL M odule Installation and Operation Guide

How to Use This Guide

Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii i

Structure of This Guid e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiv

Document Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

Text Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

Notes, Cautions, and Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv i

Related Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xvi

3Com Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xvi

Reference Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

Chapter 1 — Introduction

10BASE-FL Module Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

10BASE-FL and FOIRL IEEE Standards Comparison . . . . . . . . . . . . . . . . . 1-2

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Contents

Chapter 2 — Designing and Expanding the Network

Understanding th e General Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Basic Network Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

LAN Equivalence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Determining Maximum 10BASE-FL Link Distances . . . . . . . . . . . . . . . . . . 2-6

Calculating Maxim u m Lin k Distance . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Determining Link Bu dget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Splicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

Optical Fiber Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Maximum Link Distance Calc ulati on . . . . . . . . . . . . . . . . . . . . . 2-10

Choosing a Netwo rk Backbone Cabling Structure . . . . . . . . . . . . . . . . . 2 -13

Star Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Serial Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

10BASE-FL M od ule Co nf igu rations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

ONline Ethernet 10BASE-FL Module In stallation and Operation Guide v

10BASE-FL Bac kbon e , 10BASE-F L to-the-D e s k . . . . . . . . . . . . . . . . 2-16

Network Distance Calculation Example s . . . . . . . . . . . . . . . . . . 2-18

10BASE-FL Backbone, Unshielded Twisted Pair to-the-Desk . . . . . . 2 -20

10BASE-FB Fiber Bac kbon e, 10BASE-FL to-the-D e sk . . . . . . . . . . . . 2-23

Connecting Extern al Networ k Devices . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

Fault-Tolerant Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

Configuring Ports for Fault Tolerance . . . . . . . . . . . . . . . . . . . . . . . 2-28

Implementing Bac kbo ne Cabl e Plant Fault Toleranc e . . . . . . . . . . . 2-28

Setting Redundanc y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29

Remote Failure Signaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30

Implementing Tot al Backbone Fault Toleran ce . . . . . . . . . . . . . . . . 2 -31

Chapter 3 — Installing and Operating the Module

Precautionary Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Unpacking Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Quick Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Setting the Dip Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Setting Dip Switch SW1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Setting Dip Switch SW2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Installing the Modul e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

Configuring the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 -11

Enabling Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 -12

Selecting a Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

Enabling Port Redun danc y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

Enabling Remote Failure Sig nalin g . . . . . . . . . . . . . . . . . . . . . . . . . 3 -14

Saving Module Config uration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

Showing Mod ule Co nfi gu ration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16

Monitoring the Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

Verifying the LED and Networ k Assignm ent s . . . . . . . . . . . . . . . . . . . . 3 -19

Chapter 4 — Troubleshooting

Troubleshooting Using the Port Activity LEDs . . . . . . . . . . . . . . . . . . . . . 4-2

Troubleshooting Using the Port Status LEDs . . . . . . . . . . . . . . . . . . . . . . 4-3

RFS Troub leshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

vi ONline Eth ernet 10BASE-FL Mod ule Installation and Operation Guide

Appendix A — Specifications

General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

Optical Specification s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2

Transmitter Specificatio ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2

Receiver Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3

Supported Fiber Opt ic Cab le s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3

Fiber Optic Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Power Requiremen t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Environmental Spec ific ation s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Mechanical Specificatio ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-5

10BASE-FL Cable and Con nect or Spec ificat ion s . . . . . . . . . . . . . . . . . . .A-5

Fiber Cables and Connector s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-6

Fiber Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-6

Fiber Connector s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-6

Connecting Fib er Cabl es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-7

Appendix B — Technical Support

On-line Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Email Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

World Wide Web Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

Support from Your Netw ork Sup plier . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

Support from 3Com . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

Returning Produ cts for Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Accessing the 3Com MIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

3Com Technical Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-5

Index

ONline Ethernet 10BASE-FL Module Installation and Operation Guid e vii

viii ONline Ethernet 10BASE-FL Module Installation and Operation Guide

Figures

Figure 1-1. 10BASE-FL Mod ule Co nn ectio n s . . . . . . . . . . . . . . . . . . . 1-4

Figure 2-1. 2000 Meter Fiber Link With Mechanical Spl ice . . . . . . . 2-11

Figure 2-2. 1700 Meter Fiber Link Through Two Patch Panels . . . . . 2-12

Figure 2-3. Star-Wiring Configuration . . . . . . . . . . . . . . . . . . . . . . . 2-14

Figure 2-4. Serial Configuration Usin g 10BA SE-FL Modules . . . . . . . 2-15

Figure 2-5. All-10BASE-FL N etwo rk wi th 3 Con centr ator s . . . . . . . . 2-17

Figure 2-6. Network with 6 Concentrators . . . . . . . . . . . . . . . . . . . 2-19

Figure 2-7. Sample Configu ratio n Dist ance Calc ulati on . . . . . . . . . . 2-22

Figure 2-8. Sample Fiber Backbon e, 10 BASE-FL to-the-Desk

Figure 2-9. Thin Ethernet Segment Connecting to ONline Using an

Figure 2-10. Redundant Fiber Backbon e Co nfig uration . . . . . . . . . . . 2-29

Figure 2-11. Total Backbone Fault-Toleran t Conf iguration . . . . . . . . 2-31

Figure 2-12. Network With 3 Con cent rators . . . . . . . . . . . . . . . . . . . 2-32

Figure 3-1. 10BASE-FL Module Di p Switch Locations . . . . . . . . . . . . 3-5

Figure 3-2. Installing the 10BASE-FL Module . . . . . . . . . . . . . . . . . . . 3-9

Figure 3-3. 10BASE-FL Mod ule Co nn ectio n . . . . . . . . . . . . . . . . . . 3-10

Figure 3-4. 10BASE-FL M odules Connected w ith Redundancy/R FS

Figure 3-5. 10BASE-FL Module Faceplate and ONline System

Concentrato r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17

Configur ation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

IEEE Repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26

Enabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15

ONline Ethernet 10BASE-FL Module In st al lation and Operation Guide ix

x ONline Ether net 10BASE-FL Module Installation and Operatio n Guide

Tables

Table 1-1. 10BASE-F Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Table 2-1. Seven Basic Network Rules. . . . . . . . . . . . . . . . . . . . . . . . 2-2

Table 2-2. LAN Product Equivalent Distance s . . . . . . . . . . . . . . . . . . 2-5

Table 2-3. 10BASE-FL Module Optical Power Budg et . . . . . . . . . . . . 2-8

Table 2-4. Connector and Splice Insertion Loss. . . . . . . . . . . . . . . . . 2-9

Table 2-5. Typical Fiber Loss Characteristics . . . . . . . . . . . . . . . . . . 2-10

Table 2-6. Fiber Equivalent Distances Between Transceivers . . . . . . 2-20

Table 3-1. Quick Installation Procedures . . . . . . . . . . . . . . . . . . . . . . 3-3

Table 3-2. Dip Switch SW1 Settings . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Table 3-3. Dip Switch SW2 Settings for Switches 1 to 4 . . . . . . . . . . 3-7

Table 3-4. Dip Switch SW2 Settings for Switches 5 and 6. . . . . . . . . 3-8

Table 3-5. Interpreting the 10BASE-FL Module LED s . . . . . . . . . . . . 3 -18

Table 3-6. Network Check Codes . . . . . . . . . . . . . . . . . . . . . . . . . . 3 -19

Table 4-1. Troubleshooting Using the Port Activity LEDs . . . . . . . . . . 4-2

Table 4-2. Troubleshooting Using the Port Status LEDs. . . . . . . . . . . 4-3

Table A-1. General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

Table A-2. Transmit Power (Peak Values) . . . . . . . . . . . . . . . . . . . . .A-3

Table A-3. Receiver Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3

Table A-4. Fiber O ptic Interface Specifications. . . . . . . . . . . . . . . . . .A-4

Table A-5. Power Requiremen t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Table A-6. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .A-5

Table A-7. Mechanical Specificatio ns . . . . . . . . . . . . . . . . . . . . . . . . A-5

Table A-8. Connector Type Part Number. . . . . . . . . . . . . . . . . . . . . .A-6

ONline Ethernet 10BASE-FL Module In st al lation and Operation Guide xi

This guide is designed to help you understand the features, indicators, and installation procedure for the 3Com ONline™ Ethernet 10BASE-FL Module (Model Number 5104M-FL1). Information on troubleshooting and diagnostics are included. This guide also contains network configuration information.

Audience

This guide is intended for the following p eople at your site:

How to Use This Guide

❑ Network manager or administrator ❑ Hardware installer

ONline Ethernet 10BASE-FL Module Installation and Operation Guide xiii

Structure of This Guide

This guide contains the following chap ters and appendix: Chapter 1 - Introduction – Introduces the principal features of the

ONline Ethernet 10BA SE- FL Module. Chapter 2 - Designing and Expanding the Netw ork – Shows and

explains examples of network configurations using the ONline System Concentrator and the ONline 10BASE-FL Module.

Chapter 3 - Installing and Operating the Module – Provides illustrated procedures for installing the 10BASE-FL Module into the ONline System Concentrator.

Chapter 4 - Troubleshootin g – Pr ovides help in isolating and correcting problems that may arise during the installation process and during normal operation.

Appendix A - Specifications – Provides product dimensions, power requirements, and other specifications for the module.

Appendix B - Technical Support – Li st s th e various methods for contacting the 3Com technical support organization and for accessing other product support services.

Index

xiv ONline Eth er net 10BASE-FL Module Installation and Operation Guide

Document Conventions

This section describes document conventions.

Text Conventions

Text Convention Example

System output Courier text After you click App ly, the system

User input In the Agent I nformation Form,

displays the message Transmitting Data.

enter Support in the New Contact field.

Pathnames, Filenames

User -substituted identifiers

Key or key sequence

Button Click Cancel. Menu selection To save the configuration, select

Text emphasis, Document tit les

Plain text Before y ou begin, read the

readme.txt file located in /usr/snm/agents.

Italic text in braces

Initial-capitalized plain text

Italic text Click Apply after you add the

Use the following command to show port details:

SHOW PORT {

To refresh the screen, press Ctrl-R.

File→Save.

new search parameters.

slot

.all} VERBOSE

ONline Ethernet 10BASE-FL Module Installation and Operation Guid e xv

Notes, Cautions, and Warnings

A note indicates information that is important:

Note: Use STP lobe cables for your system.

A caution indicates a condition that may dam a ge software or hardware:

Caution: Do not put your installation diskettes on a magnetic

surface. This may damage the diskettes.

A warning indicates a condition that may threaten personal safety:

Warning: Wear eye protection w hen performing the following

maintenance procedures.

10BASE-FL Module Description

The ONline Ethernet 10BASE-FL Module is a 4-port, fiber repeater module designed for the 3Com ONline System Concentrator . The module provides 10BASE-FL backbone connectivity for Ethernet local area networks. It also provides direct 10BASE-FL to-the-desk connectivity.

The 10BASE-FL Module:

❑ Meets the 802.3 distance recommendation of two kilometers

between any two concentrators

❑ Supports network diameters up to 4 kilometers ❑ Contains built-in link redundancy fo r fault tolerance ❑ Includes extensive diagnostics for rapid troubleshooting ❑ Provides 10 Mbps performance with 100 percent collision detection

using CSMA/CD

❑ Provides backward compatibility with FOIRL-compliant equipment ❑ Supports 50 , 62.5, 85, and 100 µm fiber cable ❑ Is shipped with ST, SMA, or FC connectors ❑ Features “hot swap” cap ability

Before installing the 10BA SE- FL Module, read the ONline System Concentrator In stallation and Operation Guide.

1 - 2 ONline Ethernet 10BASE-FL Inst allation and Operation Guide

10BASE-FL and FOIRL IEEE Standards Comparison

10BASE-FL is a subpart of a IEEE standard called 10BASE-F (802.3, section

18), which standardizes three types of Ethernet-over-fiber optic cable. Table 1-1 describes each 10BASE-F standard

Table 1-1. 110BASE-F Standards

10BASE-F Standard Description

10BASE-FB “FB”indicates “fiber backbone.” Th e optimal

use for this version of fiber Ethernet is as a fiber backbone.

10BASE-FP “FP” indicates “fi ber passive” network. This

standard specifies a fiber optic connection method that passively splits the fiber optic light from each station among all the others, entirely within the optical domain.

10BASE-FL “FL” indicates “fiber link.” A superset of the

1987 IEEE FOIRL standard, the 10BASE-FL standard ensures compatibility between FOIRL and 10BASE-FL equipment. However, observe the more limiting FOIRL parameters if you interoperate with FOIRL-compliant equipment.

Theory of Operatio n

Use the 10BASE-FL Module to connect directly to a 10BASE-FL or FOIRL-compatible device (such as the 3Com model 5101T-FL1 10BASE-FL Transceiver). However, you can also use the module as your network backbone link for connecting concentrators together. Connections of both types are shown in Figure 1-1

Introduction 1 - 3

Figure 1-1. 10BASE-FL Module Connections

1 - 4 ONline Ethernet 10BASE-FL Inst allation and Operation Guide

Designing and

Expanding the Network

This chapter contains configuration information that will help you to plan your network. Install all equipment using only approved cables for proper operation. Refer to Appendix A, the section Fiber Cables and Connectors, for information on fiber cable and connector requirements.

This chapter contains the following sections:

❑ Understanding the General Rules ❑ Determining Maximum 10BASE-FL Link Distances ❑ Choosing a Network Backbone Cabling Structure ❑ 10BASE-FL Module Configurations ❑ Connecting External Network Devices ❑ Fault-Tolerant Configurations

Designing and Ex panding the Networ k 2 - 1

Understandi ng the General Rules

This section describes general rules for configuring an Ethernet network using fiber as the backbone medium. It also provides rules to ensure that your network configuration conforms to distance limitations imposed by Ethernet and networking equipment. Use these guidelines for building your network.

Refer to the sections that follow for specific rules for:

❑ Determining maximum 10BASE-FL fiber link distances ❑ Connecting various horizontal media types (10BASE-FL, 10BASE-T) to

a 10BASE-FL backbone

❑ Examples of recommended fault-tolerant configurations

Basic Network Rules

This section outlines the basic network rules and the 3Com recommendations for these rules. For additional hardware-specific information on this module, refer to Appendix A.

T able 2-1 outlines the seven basic rules to keep in mind when you construct your network.

Table 2-1. Seven Basic Network Rules

Rule Definition Recommendations/Notes

1 If pos sible, use

10BASE-FB as the backbone medium.

2 - 2 ONline Ethernet 10BASE-FL Inst allation and Operation Guide

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

Use ST-type connect ors.

Table 2-1. Seven Basic Network Rules (Continued)

Rule Definition Recommendations/Notes

2 Wire the backbone in

a star topology to isolate faults.

3 The maximum Fiber

Ethernet network diameter is 4200 meters of fiber cable.

4 Certain LAN devices

on the network shrink the maximum Fib er Ethernet network diameter to less than 4200 meters.

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

The star topology confo rm s to FDDI wiring as well -- just make sure to run at least two fiber strands to every backbone connection.

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

The 4200 meters does not include the transceiver cable (that is, drop or patch cable) that connects a device wi th 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 product s delay th e sig nal that goes through them. This is known as equivalent distance. Every microsecond delay reduces the maximum link distance. In fact, every microsecond delay shrinks the network diameter by approximately 200 meters of fiber cable. Table 2-2 lists the Equivalent Distances for other 3Com products.

Designing and Ex panding the Networ k 2 - 3

Table 2-1. Seven Basic Network Rules (Continued)

Rule Definition Recommendations/Notes

5 Assume that one

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

6 The fiber link distances

must not exceed the limits imposed by the optical power budget.

This is a conservative rule of thumb. For example, the actual equivalence is about 1.1 meters of coaxial for every meter of fiber. For simplicity, assume one meter.

In general, on 62.5 micron cable, you can go up to 4000 meters point-to-point using the ONcore or ONline Fiber Modules. If you have poor quality cable or cross many patch panels, you may have to sacrifice some distance.

Some older Ethernet fiber optic products are less powerful than ONcore Fiber Module optics. So when connecting to these products, remember that the least powerful device determines the maximum point-to-point distance.

7 When in doubt, use a

bridge.

2 - 4 ONline Ethernet 10BASE-FL Inst allation and Operation Guide

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

LAN Equivalence

LAN equivalenc e is the sum of both t he incoming and out going module port signals. Different modules, however, have different equivalent distances. Table 2-2 lists the LAN product equivalent distances.

Table 2-2. LAN Product Equivalent Distances

LAN Product

ONcore or ONline Ethernet 10BASE-FB Modules 190

Incoming sig nal to fiber port 140

Outgoing signal from fiber port 50

ONcore or ONline Ethernet 10BASE-T Modules 585

Incoming sig nal to twisted pair port 420

Outgoing signal from twisted pair port 165

ONline Ethernet FOIRL Module 560

Incoming sig nal to fiber port 330

Outgoing signal from fiber port 230

ONline Ethernet Transceiver Module 0 ONline Ethernet BNC Module 900

Incoming sig nal to BNC port 450

Outgoing signal from BNC port 450

Equivalent

Distance (meters)

ONline Ethernet Repeater Module 800

Incoming sig nal to AUI port 600

Outgoing signal from AUI port 200

IEEE Repeater 800

Designing and Ex panding the Networ k 2 - 5

Determining Maximum 10B ASE-FL Link Distanc es

This section describes how to c alculate the maximum allowable link distances between two 10BASE-FL ports.

To do this, you must know the following information:

❑ 10BASE-FL Module optical (link) power budget ❑ Fiber cable diameter (for example, 50 micron, 62.5 micron) ❑ Fiber cable light loss/km (for example, 3 dB loss/km) ❑ Number of pat ch panel connections between ports ❑ Number of splices on the link

The following tables assist you in obtaining this informatio n:

❑ Table 2-3 - Outlines the optical power budget for the 10BASE-FL

Module.

❑ Table 2-4 - Lists typical losses for various connector types. ❑ Table 2-5 - Lists typical losses for various fiber cables.

Calculating Maximum Link Distance

To calculate the maximum link distance allowed:

1. Determine the optical power budget for the 10BASE-FL p ort (Table 2-3).

2. Subtract the op tical power loss due to patch panels and splices (Table 2-4) from the optical power budget for the 10BASE-FL port.

3. Subtract the dB loss/km rating of the fiber cable (T able 2-5) from the remainder of Step 2. If the result is greater than 0 dbm, the lin k distance is valid.

2 - 6 ONline Ethernet 10BASE-FL Inst allation and Operation Guide

Determining Link Budget

As a network planner or installer , account for worst case losses through the optical connection, end-to-end, to ensure link integrity . The optical power budget represents a “worst case” assuming the transmitter is transmitting at the low end of its range.

Adhere to the IEEE 802.3 10BASE-FL specification which states that the minimum distance supported between two 10BASE-FL ports is 2 kilometers.

If the link between two 10BASE-FL ports is:

❑ Less than 2 kilometers and contains minimal losses (that is, only one

splice or connector and typical fiber cab le attenuation) you do not need to calculate the optical budget for the link.

❑ If you must exceed 2 kilometers, or if you have multiple splices in the

cable, you must calculate the optical power budget.

Note: When connecting a 10BASE-FL product to an FOIRL

product, do not exceed the 1 kilometer maximum distance defined by the 802.3 FOIRL specification. Because 10BASE-FL is backw a rd compatible with FOIRL , yo u can make mixed 10BASE-FL/FOIRL connections. However , to interoperate 10BASE-FL and FOIRL equipment, observe the more limiting restrictions of the FOIRL specification.

T able 2-3 provides the Transmit Optical Power ranges and required Receiver Optical Power sensitivity levels for the 10BASE-FL Module.

Designing and Ex panding the Networ k 2 - 7

Note: The values in Table 2-3 are peak power values. You

determine average o ptical power by subtr acting 3 dBm from the peak value. All of the exam ples provid ed in the pages that follow refer to peak optical power. Note that higher optical power is represented by a smaller negative number (for example, -12 dBm is greater than -20 dBm).

Table 2-3. 10BASE-FL Module Optical Power Budget

Cable Si ze

Used

(microns)

50/125

T rans mit

Pow e r

(dBm)

(Peak)

-16.5 ± 3.0 -8.0 to -29.5 10.0 None

Receive

Power

Range

(dBm) (Peak)

Optical

Power

Budget

(dB)

NA 0.20

62.5/125

-12.0 ± 3.0 -8.0 to -29.5 14.5 None

NA 0.275

85/125

-9.0 ± 3.0 -8.0 to -29.5 17.5 >2.0 dB

NA 0.29 100/140

-6.5 ± 3.0 -8.0 to -29.5 20.0 >4.5 dB

NA 0.29

Atte nua tion

It is possible for receivers to receive too m uch light when:

❑ Using 85/12 5 and 100/140 micron fiber cables

Lin k Loss Required

(dB)

(ONline to

ONline)

❑ Ports are close together on a link

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