3Com 5112M-TPLS installation and operation guide Sample Configuration Distance Calculation

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Using the sample configuration below, identify the two transceivers that are likely to be the greatest fiber equivalent distance apart. In this case, they are 10BASE-T Transceivers A and B.

Figure 2-1. Sample Configuration Distance Calculation

To determine if your network configuration is legal:

1.Use 4.2 km (4200 m) since this is the maximum network diameter for a pure fiber network (see Rule 3).

2.Calculate the equivalent distances for each concentrator, and subtract the totals from 4200 (refer to Figure 2-1 for details).

3.Subtract all cable lengths between the two transceivers. If the result is greater than zero, the configuration is within legal Ethernet limits (see Rule 5).

For the configuration shown in Figure 2-1 to work, ensure the fiber equivalent distance between transceiver A and transceiver B is less than 4200 meters. As the calculation illustrates, 1560 meters remain for expansion in this configuration.

Designing and Expanding the Network 2 - 9

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Contents Page VDE Class B Compliance Restricted Rights Page Contents Installing and Operating the Module Troubleshooting Appendix B Technical Support Figures Page Tables Page Audience How to Use This GuideStructure of This Guide Convention Indicates Example Document ConventionsUsr/snm/agents Related Documents Reference Documents 3Com DocumentsPage ONline 10BASE-T Security Module IntroductionApplication Theory of OperationONline 10BASE-T Security Module Application ONline ManagementPage Designing and Expanding the Network Basic Network Rules Understanding the General RulesRule Definition Recommendations/Notes Seven Basic Network RulesCertain LAN devices Seven Basic Network Rules LAN Product Equivalent Distances LAN EquivalenceLAN Product Equivalent Fiber Fiber Backbone, Twisted Pair To-The-Desk Fiber Backbone, Twisted Pair To-The-Desk Example Sample Configuration Distance Calculation Maximum Link Distance on Twisted Pair Twisted Pair Backbone, Twisted Pair To-The-DeskCable Gauge Supports Link Distances Up To Unshielded Twisted Pair Network Patch PanelsRedundant Links Redundant Twisted Pair ConfigurationDesigning and Expanding the Network 2 Page Installing and Operating the Module Step Procedure Reference Precautionary ProceduresQuick Installation Chart Procedures for Completing InstallationInstalling the Module Unpacking Procedures Security Module Dip Switch SW1 Location Setting the Dip SwitchSwitch Network Selection Switch Settings DIP Switch SW1 Network Selection SettingsSwitch Function Factory Setting DIP Switch SW1 Security and Link Integrity SettingsOff On Installing the Cable Tie-Wrap Kit Installing the ModuleAttaching the Tie-Wrap Bracket to the Module Attaching Cables With 90 Connectors Installing an ONline 10BASE-T Security Module Installing the ModuleONline 10BASE-T Security Module Cable Connection Configuring the Module Network Assignment Port EnablePort Redundancy Module Security Link IntegrityReverting Module Configurations Saving Module ConfigurationsAutopartition Threshold Show Module Show Module Verbose Show Port Show Port Verbose Showing Module ConfigurationsMonitoring the Front Panel Security Module Faceplate Color State Indicates Name Interpretation of the Security Module LEDsLED and Network Verification LED State Network ConfigurationNetwork Check Codes Page Configuring Security Features Quick Reference for Configuring the Security Module Quick Reference for Configuring SecurityProcedure Command SET Security Autolearn Eavesdropping Security Configuring Security FeaturesExample of Eavesdropping Security Intrusion DetectionExample of Intrusion Detection Defining Port Security TypeDefining Port Action on Intrusion Enabling Ports Configuring Autolearning MaskConfiguring Autolearning Autolearn capture done learned 0 addresses total Defining a MAC Address Manually Downloading the Autolearning Database Configuring Security Mode Saving Security Configurations Showing Security ConfigurationsReverting Security Configurations Showing Port Configurations Eavesdrop None ETHERNET1 Showing Security Autolearn Showing Security Intruder List Clearing the MAC Address Table Clearing Security ConfigurationsClearing the Security Intruder List Clearing the Autolearning DatabaseEMM Security Snmp Variables Using 3Com MIB Security VariablesUsing the Security Module Snmp Variables Configuring Security Features 4 Page Troubleshooting TroubleshootingTroubleshooting Using the Port Status LEDs Troubleshooting Using the Status LEDsTroubleshooting Using the Port Status LEDs Troubleshooting Using the Activity LEDs Troubleshooting Using the Activity LEDsLED State Possible Problem Troubleshooting Solutions Technical Assistance Page Electrical Specifications SpecificationsMechanical Specifications Environmental SpecificationsGeneral Specifications Pin Connector and Cable Figure A-1 -Pin Cable Male and Female Connectors Polarity Table A-1 -Pin Cable Pinouts and Port AssignmentsHub Trans Ceiver Port # FunctionPort # Twisted Pair Connectors and CablesHub Trans HubFigure A-2. RJ-45 Connector Pinouts Twisted Pair ConnectorsTwisted Pair Cables On-line Technical Support Technical SupportEmail Technical Support Support from Your Network SupplierWorld Wide Web Site Support from 3Com Returning Products for Repair Accessing the 3Com MIB3Com Technical Publications Page Index Activity LEDs, 3-18,3-20 Quick Reference Chart Security Type Default Setting Index