Chapter Calculating transmission distance | Nortel Networks 10396EA

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Chapter 2

Calculating transmission distance

This chapter will help you determine the maximum transmission distance for your CWDM network configuration.

This chapter includes the following topics:

•“About transmission distance and optical link budget” next

•“Point-to-point transmission distance” on page 29

•“Mesh ring transmission distance” on page 30

•“Hub and spoke transmission distance” on page 33

About transmission distance and optical link budget

By calculating the optical link budget, you can determine a link’s transmission distance, or the amount of usable signal strength between the point where it originates and the point where it terminates. The loss budget, or optical link budget, is the amount of optical power launched into a system that is expected to be lost through various mechanisms acting on the system, such as the absorption of light by molecules in an optical fiber. Factors that affect transmission distance include:

•fiber optic cable attenuation (typically 0.25 dB - 0.3 dB per kilometer)

•network devices the signal passes through

•connectors

•repair margin (user-determined)

Note: Insertion loss budget values for the optical routing system CWDM

OADM and CWDM OMUX include connector loss.

Installation and Networking Guidelines for Optical Routing

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Nortel Networks 10396EA Chapter Calculating transmission distance, About transmission distance and optical link budget

Contents

Installation and Networking Guidelines for Optical Routing 212257-B Copyright 2002 Nortel Networks Canada requirements only Installation and Networking Guidelines for Optical Routing Nortel Networks Inc. software license agreement Installation and Networking Guidelines for Optical Routing 212257-B Contents Contents Chapter Installing the shelf, OADM, and Omux Figures Figures 212257-B Tables Tables 212257-B Component Function Preface Before you begin Hard-copy technical manualsPreface Technical Solutions Center Telephone How to get help Preface 212257-B Wavelength division multiplexing Chapter Describing the optical routing system Parts of the optical routing system Parts of the optical routing systemGigabit interface converter description Describing the optical routing system Cwdm Gbic transceiver and label Optical add drop multiplexer description Cwdm Oadm network and equipment side connections Network add/drop ring application Optical multiplexer/demultiplexer description Cwdm Oadm ring configuration example Cwdm OMUX-4 Cwdm OMUX-8 network and equipment side connections Cwdm Omux in a point-to-point application Cwdm Omux in a ring application Cwdm Omux point-to-point configuration example Cwdm Omux ring configuration example Describing the optical routing system 212257-B About transmission distance and optical link budget Chapter Calculating transmission distance How to calculate expected loss budget How to calculate maximum transmission distanceCalculating transmission distance Point-to-point transmission distance Point-to-point network configuration example Point-to-point signal loss values Mesh ring transmission distancePoint-to-point maximum transmission distance calculations Mesh ring network configuration Mesh ring maximum transmission distance calculations Mesh ring signal loss values Hub and spoke transmission distance Hub and spoke network configuration Hub and spoke maximum transmission distance calculations Hub and spoke signal loss values Chapter Installing the shelf, OADM, and Omux Preparing for installationExceeding class 1 power level warning Installing the shelf, OADM, and Omux Environmental and physical requirementsElectrostatic discharge Installing the shelf Shelf with plug-in module in 19-inch rack Inserting a Cwdm Oadm or a Cwdm Omux Cabling a Cwdm Oadm Cabling a Cwdm Oadm or a Cwdm Omux Cabling a Cwdm Oadm Cabling a Cwdm OMUX-4 Cabling a four-channel Cwdm Omux Cabling an eight-channel Cwdm Omux Cabling an Cwdm OMUX-8 Removing a Cwdm Oadm or a Cwdm Omux Cwdm Oadm specifications Appendix a Cwdm Oadm specifications Appendix a Cwdm Oadm specifications 212257-B Cwdm Omux specifications Cwdm Omux specificationsAppendix B Appendix B Cwdm Omux specifications 212257-B Precautions Appendix C Handling and cleaning fiber optic equipment Cleaning Fiber Optic Connectors Appendix C Handling and cleaning fiber optic equipmentTools and Materials Cleaning Single SC and FC Connectors Cleaning Duplex SC Connectors Cleaning Receptacle or Duplex Devices Page Glossary Glossary Dwdm See optical fiber Group of circuits connected at one point on a network See MMF Ndsf An optical wavelength band for WDM optical communications Device that does not require a source of energy to function See SMF WDM Glossary 212257-B Cwdm Omux Index OMUX, Cwdm Index Index Index 212257-B