Nortel Networks 10292FA How to calculate expected loss budget, Calculating transmission distance

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28Chapter 2 Calculating transmission distance

How to calculate expected loss budget

To calculate the expected loss budget for a proposed network configuration:

1Identify all points where signal strength will be lost.

2Calculate the expected loss for each point.

3Add the expected losses together.

How to calculate maximum transmission distance

The examples in this chapter use the following assumptions and procedure for calculating the maximum transmission distances for networks with CWDM GBICs, CWDM OADMs, and CWDM OMUXs.

Assumptions

The examples assume use of the values and information listed in Table 2.

Table 2 Assumptions used in calculating maximum transmission distance

Item	Assumption

Cable	Single mode fiber optic cable (SMF)

Repair margin	01
Maximum link budget	30 dB2

System margin	3 dB (allowance for misc. network loss)

Fiber attenuation	.25 dB per kilometer

Operating temperature	0 - 40°C (32 - 104°F)

CWDM OADM expected loss3	Use of “CWDM OADM specifications” on page 45

CWDM OMUX expected loss3	Use of “CWDM OMUX specifications” on page 47

1Use your organization’s expected repair margin for percentage of the total fiber plant loss for each site-to-site fiber span.

2From specifications in Installing CWDM Gigabit Interface Converters, part number 212256-B

3Multiplexer loss values include connector loss.

212257-B

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Contents Installation and Networking Guidelines for Optical Routing Copyright 2002 Nortel Networks 212257-BInstallation and Networking Guidelines for Optical Routing Canada requirements onlyNortel Networks Inc. software license agreement Installation and Networking Guidelines for Optical Routing 212257-B Contents Chapter Installing the shelf, OADM, and Omux ContentsFigures Figures 212257-B Tables Tables 212257-B Preface Component FunctionHard-copy technical manuals Before you beginPreface How to get help Technical Solutions Center TelephonePreface 212257-B Chapter Describing the optical routing system Wavelength division multiplexingParts of the optical routing system Gigabit interface converter descriptionDescribing the optical routing system Parts of the optical routing systemOptical add drop multiplexer description Cwdm Gbic transceiver and labelNetwork add/drop ring application Cwdm Oadm network and equipment side connectionsCwdm Oadm ring configuration example Optical multiplexer/demultiplexer descriptionCwdm OMUX-4 Cwdm Omux in a point-to-point application Cwdm OMUX-8 network and equipment side connectionsCwdm Omux point-to-point configuration example Cwdm Omux in a ring applicationCwdm Omux ring configuration example Describing the optical routing system 212257-B Chapter Calculating transmission distance About transmission distance and optical link budgetHow to calculate maximum transmission distance How to calculate expected loss budgetCalculating transmission distance Point-to-point network configuration example Point-to-point transmission distanceMesh ring transmission distance Point-to-point signal loss valuesPoint-to-point maximum transmission distance calculations Mesh ring network configuration Mesh ring signal loss values Mesh ring maximum transmission distance calculationsHub and spoke network configuration Hub and spoke transmission distanceHub and spoke signal loss values Hub and spoke maximum transmission distance calculationsPreparing for installation Chapter Installing the shelf, OADM, and OmuxExceeding class 1 power level warning Environmental and physical requirements Installing the shelf, OADM, and OmuxElectrostatic discharge Installing the shelf Inserting a Cwdm Oadm or a Cwdm Omux Shelf with plug-in module in 19-inch rackCabling a Cwdm Oadm or a Cwdm Omux Cabling a Cwdm OadmCabling a Cwdm Oadm Cabling a four-channel Cwdm Omux Cabling a Cwdm OMUX-4Cabling an eight-channel Cwdm Omux Cabling an Cwdm OMUX-8 Removing a Cwdm Oadm or a Cwdm Omux Appendix a Cwdm Oadm specifications Cwdm Oadm specificationsAppendix a Cwdm Oadm specifications 212257-B Cwdm Omux specifications Cwdm Omux specificationsAppendix B Appendix B Cwdm Omux specifications 212257-B Appendix C Handling and cleaning fiber optic equipment PrecautionsAppendix C Handling and cleaning fiber optic equipment Cleaning Fiber Optic ConnectorsTools 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 Index Cwdm OmuxIndex OMUX, CwdmIndex Index 212257-B